GI & Hepatology Clinical Calculators

They define different populations rather than competing on one — APASL excludes previously decompensated patients and EASL-CLIF includes them, so a patient can meet one definition and not the other.

AARC outperformed MELD in the APASL cohort, largely because MELD has no representation of encephalopathy or lactate — but MELD-Na remains the allocation instrument and AARC is not.

Child-Pugh describes chronic hepatic function and can be near-normal in a patient with grade III AARC — it is the baseline, not the acute assessment.

ABC generally out-discriminates AIMS65 for 30-day mortality and works in lower as well as upper GI bleeding, at the cost of a few more inputs and explicit comorbidity terms.

Different jobs: Glasgow-Blatchford identifies low-risk upper GI bleeds who can avoid intervention or admission, while ABC predicts 30-day mortality across upper and lower bleeding — use them together, not interchangeably.

The same disorder family separated by which symptom dominates — pain or vomiting.

Episodic and incapacitating with long well intervals, versus frequent and grumbling.

The residual category that can only be used once abdominal migraine has been considered and excluded.

Maddrey's DF answers whether a patient has severe disease at all; ABIC answers how severe, splitting that severe group into three tiers with 90-day survival of 100%, 70% and 25%.

ABIC and Lille answer different questions at different times — ABIC stratifies baseline risk at admission, Lille measures corticosteroid response at day 7 — and combining a static score with Lille predicts survival better than either alone.

GAHS is built to predict who benefits from corticosteroids; ABIC is built to predict who survives — overlapping inputs, but they are answering different clinical questions.

Use AIMS65 for the mortality question and Glasgow-Blatchford for the discharge/intervention question — they are complementary, and a low AIMS65 is not a safe-discharge signal.

The newer ABC score generally out-discriminates AIMS65 for 30-day mortality and works in lower as well as upper GI bleeding, at the cost of a few more inputs and explicit comorbidity terms.

Both are pre-endoscopy mortality tools and perform comparably; AIMS65 avoids the shock and comorbidity categories that Rockall requires, using labs and mental status instead.

Comparable overall, but ALBI is objective and subdivides Child-Pugh A into two prognostically distinct groups — which is where most patients with hepatocellular carcinoma actually sit.

Different purposes entirely — MELD 3.0 ranks transplant priority by short-term mortality, ALBI grades hepatic reserve to decide whether a liver will tolerate cancer treatment.

Complementary halves of the same assessment — Milan describes the tumour, ALBI describes the liver it sits in, and transplant candidacy needs both.

The adult home for the same behaviour — Rome IV splits supragastric from gastric belching in adults, and gives children a distension-based disorder instead.

Both feature distension, but only aerophagia empties overnight and requires the air to be swallowed.

The commonest alternative explanation for a distended child, and the one most likely to be diagnosed by default.

This converter measures how much someone drinks; CAGE screens for whether that drinking has become dependent or harmful — quantity and disorder are related but distinct, and neither substitutes for the other.

Quantifying alcohol intake helps establish that liver disease is alcohol-related; Maddrey's DF then grades the severity of an acute alcohol-related hepatitis once that diagnosis is made.

Different site, different mechanism — but the same trap of escalating investigation in the absence of structural disease.

Both are pelvic floor disorders treated with biofeedback, but one is defined by pain and the other by impaired evacuation.

Opposite symptoms from the same anatomical region — and both are under-disclosed for the same reason.

FIB-4 is the usual first-line choice in guideline pathways because it needs no local reference range — but APRI is a worthwhile cross-check, and it was the better performer for cirrhosis specifically in its derivation cohort.

Elastography is more accurate and is preferred wherever it exists; APRI's role is in settings where it does not, which is why WHO guidance names APRI rather than elastography for hepatitis B assessment in resource-limited care.

Not alternatives — BISAP predicts severity within the first 24 hours, and the revised Atlanta classification is the severity it is predicting.

Ranson's shares the 48-hour timing but answers the opposite question — it predicts severity from admission and 48-hour values, while Atlanta defines it from organ failure and complications.

A contemporaneous alternative that adds a fourth 'critical' category for persistent organ failure plus infected necrosis; comparative studies find the two perform similarly, and Atlanta has been more widely adopted.

CTSI grades what the scan shows; the revised Atlanta classification grades what the patient does — and the scan is unreliable in the window where the classification is being decided.

Both are deliberately minimal bedside instruments built for one narrow decision — and both are easy to over-read.

Two colitides that look alike on the ward — and the scores are not interchangeable in either direction.

Both are bedside scores in acute lower gastrointestinal presentations, built for opposite ends of the risk spectrum.

AUDIT is the better instrument for current drinking; CAGE screens for lifetime dependence and contains no question about how much anyone drinks.

AUDIT-C is enough when the question is whether someone drinks too much; use all ten items when the question is whether they are dependent.

They answer different questions and work best together — AUDIT grades risk behaviour, a unit calculation converts what the patient actually described into grams.

FIB-4 is clearly the stronger test — AUROC 0.86 against BARD's 0.77 in direct comparison, and it spares 62% of biopsies against BARD's 38% — so BARD is justified only when a platelet count is unavailable.

The NAFLD Fibrosis Score discriminates better and rules out advanced fibrosis in more patients, but BARD needs neither albumin nor a platelet count and gives a binary answer rather than a wide indeterminate zone.

BARD outperformed APRI for advanced fibrosis in steatotic liver disease (AUROC 0.77 versus 0.67) — APRI was derived in hepatitis C and does not transfer well to MASLD.

HVPG remains the reference standard and Baveno VII does not claim otherwise — but it requires catheterisation, so the realistic comparison is against no measurement at all.

Both aim to avoid unnecessary endoscopy, but Baveno VII needs elastography and EVendo needs only routine blood tests — availability is the deciding factor.

Different stages of the same pathway — FIB-4 triages who needs elastography at all, and Baveno VII takes over once a stiffness measurement exists.

Child-Pugh describes established liver dysfunction; Baveno VII identifies risk before dysfunction appears, in patients Child-Pugh would call class A.

Overlapping but not identical — aerophagia describes excessive air swallowing reaching the stomach, whereas supragastric belching involves air that never gets there.

Belching is a supportive feature of functional dyspepsia rather than a competing diagnosis — the question is which symptom is dominant.

Belching accompanies reflux commonly, but supragastric belching is a distinct behaviour that acid suppression does not treat — and it can also trigger reflux events.

Substantial symptom overlap, opposite management — dyspepsia is treated medically and biliary pain leads toward surgery, so getting this wrong sends a patient to theatre unnecessarily.

Rome IV retired this classification — the former type III, biliary pain with no objective abnormality, no longer supports intervention after the EPISOD trial.

Different presentation and a far higher evidential bar — the pancreatic disorder requires documented recurrent pancreatitis, not pain alone.

Use BISAP on day one and Ranson once 48 hours of data exist — pooled across 17 studies Ranson is the more sensitive and BISAP the more specific, and only BISAP is available when the triage decision has to be made.

They answer different questions at different times: BISAP predicts mortality on day one, CTSI grades local complications on contrast CT at 72 hours or later.

APACHE II is at least as accurate but needs around a dozen variables; BISAP achieves comparable discrimination from five bedside criteria, which is why it displaced APACHE II for routine use.

Aronchick is a single global rating scored before cleansing; BBPS is segmental and scored after, which is why BBPS can identify the unseen segment that a global rating hides.

Both are segmental and validated; Ottawa also scores fluid volume separately, which makes it more granular but harder to apply consistently in routine practice.

A free-text rating cannot support an interval decision — 'fair preparation' is uninterpretable three years later, which is the problem BBPS exists to solve.

They work together rather than competing: Rome IV decides whether it is irritable bowel syndrome, and Bristol decides which subtype — you cannot complete the Rome IV subtyping step without stool form.

Form predicts colonic transit better than frequency does, which is why the scale exists — someone opening their bowels daily can still be constipated.

Use AUDIT when the question is current hazardous or harmful drinking; CAGE is the narrower, dependence-focused tool and, in a head-to-head comparison, identified a subset of the patients AUDIT flagged, never a group of its own.

AUDIT-C takes about the same time as CAGE and asks the question CAGE cannot — how much, how often, and how often heavily.

Clinically indistinguishable during an episode — Rome IV defines this one in terms of the other, and only cannabis exposure and response to cessation separate them.

Distinguished by pattern rather than cause — cannabinoid hyperemesis is episodic with well periods, while chronic nausea and vomiting syndrome is continuous or near-continuous.

The iatrogenic sequel — CAPS patients escalated onto opioids frequently develop it, and the treatment reverses from adding analgesia to withdrawing it.

Mutually exclusive by mechanism — IBS pain is defined by its relationship to defecation, and CAPS by the absence of that relationship.

CAPS requires that structural disease does not explain the pain — but a structural diagnosis can coexist if its activity does not account for the symptoms.

Use the CDAI when a trial-grade, diary-based measure is required, and the Harvey-Bradshaw Index for routine clinical care — the two correlate well but are not interchangeable for an individual patient.

The CDAI measures how the patient feels; endoscopic and biomarker measures show whether the bowel is inflamed, and the two agree less often than is comfortable.

A normal Chicago v4.0 study is a prerequisite for the Rome IV diagnosis, not merely a negative finding.

Hypercontractile oesophagus and distal oesophageal spasm are the two patterns that must be excluded before chest pain is called functional — and both now need symptoms to be diagnosed at all.

Manometry positions the pH probe and excludes motor disease; it does not diagnose either condition.

Use MELD-Na or MELD 3.0 for prognosis and transplant priority, and Child-Pugh whenever you need a class — the two answer different questions and cannot be converted into one another.

ALBI is the better choice when you want liver function graded objectively in hepatocellular carcinoma — it uses only albumin and bilirubin, so it removes the subjectivity that limits Child-Pugh.

Switch to CLIF-SOFA when the question is acute-on-chronic liver failure rather than chronic severity — Child-Pugh was not built for an acutely deteriorating patient and does not count organ failures.

Separated by pattern, not severity — this disorder is continuous, cyclic vomiting syndrome is episodic with genuinely well periods between attacks.

Overlapping populations rather than distinct diseases — the label often depends on whether an emptying study was done, and emptying correlates poorly with symptoms.

An explicit Rome IV exclusion, and the one most often missed — patients call effortless regurgitation vomiting, and the two have completely different treatments.

CLIF-C OF replaced CLIF-SOFA for diagnosis and CLIF-C ACLF is the better prognostic score — CLIF-SOFA is the original instrument, not the current best one.

They grade different syndromes rather than competing on the same one — APASL excludes previously decompensated patients, EASL-CLIF includes them, so the two frameworks are not scoring the same population.

MELD-Na ranks waiting-list priority from four laboratory values; CLIF-SOFA identifies a syndrome across six organ systems and predicts short-term mortality better in that population.

Child-Pugh grades chronic hepatic function and is not built for an acute deterioration — CLIF-C ACLF reduced prediction error by 19–28% against it in ACLF.

Not alternatives on the same timeline — BISAP is calculated within the first 24 hours from clinical and laboratory data, while CTSI needs imaging that is most informative from 72 hours onward; many patients are appropriately scored with both, sequentially.

The modified index has shown a closer correlation with patient outcome — particularly organ failure — than the original CTSI, in the study that introduced it, but the original remains widely used and the two point systems are not interchangeable.

Indistinguishable on the episodes — Rome IV defines cannabinoid hyperemesis in terms of this disorder, and only cannabis exposure and response to cessation separate them.

Separated by pattern, not severity — cyclic vomiting has discrete episodes with well periods, while chronic nausea and vomiting syndrome is continuous.

Different mechanism entirely — rumination is effortless post-prandial regurgitation without retching, not episodic vomiting.

One is the prerequisite for the other — and the reason to test is that the treatments diverge completely.

IBS with constipation is an equally valid entry point — the defecation disorder can sit on top of either.

Opposite symptoms that frequently coexist — and the evacuation disorder should be treated first.

Histology remains the diagnostic standard — EREFS describes appearance and cannot diagnose or exclude the disease.

Different diseases in the same organ — LA grades reflux erosions, EREFS grades the features of eosinophilic oesophagitis.

Complementary — EREFS describes what the oesophagus looks like, Chicago describes how it moves, and dysphagia often needs both.

The same lesion, entirely different questions — is it bleeding, versus is it cancer.

Pre-endoscopy triage against post-endoscopy follow-up planning — opposite ends of the same admission.

Both are descriptive endoscopic classifications rather than risk models, but only EGUS carries a probability.

Baveno VI is the guideline-endorsed route to avoiding endoscopy but requires transient elastography; EVendo reaches a similar decision from blood tests alone, which makes it usable where elastography is not.

Child-Pugh grades overall cirrhosis severity and does not predict varices; EVendo predicts varices needing treatment specifically, and its own performance is stratified by Child-Pugh class.

Opposite clinical moments — EVendo decides whether an asymptomatic patient with cirrhosis needs elective screening endoscopy, while the Glasgow-Blatchford score triages a patient who is already bleeding.

The differential that reverses the treatment — overflow leakage around impacted stool needs disimpaction and laxatives, not antidiarrhoeals.

Opposite symptoms, overlapping physiology — both involve pelvic floor dysfunction, and both respond to biofeedback.

Frequently coexist and are rarely asked about together — treating the diarrhoea often resolves the incontinence.

Same target, different inputs — both estimate at-risk NASH, but FNI needs only bloods while FAST needs a FibroScan, so FNI screens broadly and FAST confirms more accurately where elastography is available.

They answer different questions — FIB-4 estimates advanced fibrosis from bloods, FAST estimates at-risk NASH from a FibroScan plus AST — so FIB-4 triages fibrosis risk cheaply and FAST characterises the active fibrotic phenotype.

Both use elastography, but FAST relies on the widely available FibroScan while MEFIB relies on MRE and reached a higher positive predictive value head-to-head — access versus accuracy.

They are sequential, not alternative — the Fatty Liver Index establishes whether steatosis is present, and FIB-4 then establishes whether it has caused advanced fibrosis, which is the question that carries the prognosis.

The Fatty Liver Index is a steatosis-detection tool validated against ultrasound; the NAFLD Fibrosis Score is a fibrosis tool validated against liver biopsy — different targets, different reference standards, and neither substitutes for the other.

Both are three- or four-item scores in steatotic liver disease, but the Fatty Liver Index finds fat while BARD rules out fibrosis — using either for the other's purpose is a category error.

FIB-4 is generally the better first-line rule-out and the one guideline pathways specify — APRI is simpler but uses your laboratory's AST upper limit of normal, which makes it less portable between services.

Use FIB-4 first because it needs nothing beyond a standard blood panel; NFS adds BMI, diabetes status and albumin, which makes it more specific to metabolic liver disease but harder to run automatically over existing lab data.

Elastography is the more accurate test and the usual next step after an indeterminate or high FIB-4 — but it needs a machine, an operator and a fasted patient, which is exactly why FIB-4 comes first.

They answer different questions — FIB-4 estimates advanced fibrosis, FNI estimates at-risk NASH — so use FIB-4 to triage fibrosis risk and FNI when the question is specifically whether treatable steatohepatitis activity is present alongside it.

The NAFLD Fibrosis Score targets advanced fibrosis; FNI targets at-risk NASH — pick the score whose endpoint matches your decision, and note both are blood-only and can be run over existing labs.

Same endpoint, different inputs — both estimate at-risk NASH, but FNI needs only bloods while FAST needs a FibroScan (liver stiffness plus CAP plus AST), so FNI screens and FAST confirms where elastography is available.

Forrest predicts rebleeding from the endoscopic appearance; Rockall predicts mortality by adding age, shock and comorbidity to the endoscopic findings — use them together after endoscopy.

Glasgow-Blatchford is a pre-endoscopy triage score with no endoscopic input; Forrest is an at-endoscopy classification — they operate at different moments and do not compete.

IBS has to be excluded first — the discriminator is whether the pain relates to defecation or to stool change.

The disorder most often missed on the way to this category, usually because nobody asked about pallor.

The adult disorder this most resembles — continuous pain with central features, managed the same way.

Mutually exclusive — bloating is a supportive feature of IBS, and only becomes this diagnosis when it predominates and IBS criteria are not met.

The cross-chapter exclusion — bloating that follows meals alongside early satiation is a gastroduodenal problem, not a bowel one.

A frequently invoked and genuinely contested alternative — breath testing has poor specificity, and a positive result does not reliably predict response to antibiotics.

These are the treatable motor causes of the same symptom, and excluding them is a Rome IV criterion — which means manometry is mandatory rather than optional.

Reflux hypersensitivity can present as chest pain too — the separator is whether reflux monitoring shows the symptoms tracking reflux events.

Not alternatives but frequent companions — each amplifies the other, and treating only one usually disappoints.

Mutually exclusive by design — abdominal pain related to defecation makes it IBS with constipation, and the boundary is taxonomic rather than mechanistic.

Not an alternative but a next step — a functional defecation disorder requires functional constipation or IBS-C first, and it is what laxative-refractory constipation frequently turns out to be.

Same six symptom items, different trigger — and Rome IV asks that research studies keep them apart while accepting they overlap in practice.

Mutually exclusive, separated only by whether abdominal pain is predominant — and that boundary is taxonomic rather than mechanistic.

Not a competing diagnosis but the single most important thing to exclude — it presents identically and has a specific, effective treatment.

Invisible at colonoscopy and diagnosed only on biopsy — so a normal-looking colon without biopsies does not exclude it.

Overlapping symptoms and a blurred boundary — a gastric emptying study separates them on paper, but the distinction predicts treatment response less well than it should.

Not mutually exclusive — Rome IV explicitly permits coexistence, and the overlap is common enough that assuming one diagnosis excludes the other is a frequent error.

A separate entity in Rome IV rather than a subtype — if eradication produces sustained relief, the diagnosis was H. pylori-associated dyspepsia and not the functional disorder.

The exclusion that makes manometry mandatory — achalasia presents identically at the bedside and is specifically treatable, so a functional label without manometry risks missing it entirely.

The exclusion that makes biopsies mandatory — it causes exactly this symptom, is often endoscopically normal, and is specifically treatable.

Mutually exclusive and frequently confused — globus is felt between meals and eases with eating, while functional dysphagia is food sticking during swallowing.

One test result separates them — both have normal acid exposure, but reflux hypersensitivity has symptoms that track reflux events and functional heartburn does not.

GORD has abnormal acid exposure; functional heartburn has normal acid exposure and no symptom association, and the two need opposite treatment strategies.

Different symptoms, mutually exclusive criteria — functional chest pain requires the absence of heartburn, so a patient cannot meet both sets.

Sequential, not competing — GALAD decides who to image, LI-RADS decides what the image shows.

The comparison GALAD exists to win, and the margin is largest exactly where it matters — early-stage disease.

Opposite ends of the same patient journey — one asks whether there is a cancer, the other what can be done about it.

Use Maddrey's DF as the entry threshold for severe disease, and GAHS to decide whether steroids are likely to help within that group — GAHS was built specifically to correct the older score's blind spots.

They answer sequential questions rather than competing — GAHS helps decide whether to start corticosteroids, and the Lille model decides at day 7 whether to continue them.

Mutually exclusive by definition — globus requires the absence of dysphagia, so a patient with food actually sticking is assessed as functional dysphagia instead.

Not a competing diagnosis but a required exclusion — and the only cause of a globus sensation with a specific endoscopic treatment.

An overlapping and contested label — Rome IV requires evidence that reflux is the cause rather than accepting the assumption that underpins most LPR diagnoses.

Use Glasgow-Blatchford before endoscopy to decide on admission and intervention, and Rockall after endoscopy to estimate mortality and rebleeding — they answer different questions and the evidence separates them cleanly.

AIMS65 is quicker to calculate and better at predicting mortality; GBS is better at predicting the need for intervention, which is usually the more actionable question at presentation.

Glasgow-Imrie is the practical choice on a general ward — eight variables from routine bloods and one gas, with a single criteria set for all aetiologies — while Ranson is more sensitive on paper but depends on fluid-balance and serial-haematocrit data that is often missing.

BISAP answers the question 48 hours earlier, which is the only question that matters on admission; Glasgow-Imrie is the better-founded 48-hour statement, so they belong in sequence rather than in competition.

Glasgow-Imrie grades how badly the patient is affected and CTSI grades how badly the pancreas is damaged; the two disagree often enough that using either alone will miss something.

Not a competitor but the reference standard Glasgow-Imrie is measured against — Atlanta defines what 'severe' means retrospectively, while Glasgow-Imrie predicts it prospectively at 48 hours.

Use HBI for routine clinical care and CDAI when a trial-grade, diary-based instrument is specifically required — the two correlate well but are not interchangeable at the individual-patient level.

The Harvey-Bradshaw Index measures symptoms and the biomarkers measure inflammation; when they disagree, the biomarker should usually drive the decision.

The same question on the same day — graded versus binary, and each sees something the other cannot.

Truelove and Witts defines the admission; the Ho index assesses whether treatment is working three days into it.

The paediatric equivalent decision point — same logic, different instrument and different day.

Two benign conditions of the same age group that frequently coexist — and attributing the crying to the regurgitation is how infants end up on acid suppression.

Crying with a clear pattern — ten minutes of straining before a soft stool — is dyschezia, not colic, and the distinction changes what you tell the family.

The commonest organic explanation to consider, and the one most likely to be diagnosed without ever being confirmed.

Stool consistency decides it — soft means dyschezia, hard means constipation, and the two are treated in opposite directions.

The diagnosis dyschezia must not be allowed to obscure, and the discriminators are historical rather than symptomatic.

Patterned crying tied to defecation is dyschezia; unpatterned, unpredictable crying is colic — and a baby can plausibly have both.

Overlapping ages and overlapping parental distress — but crying is not evidence of reflux, and treating it as such is the main reason infants end up on acid suppression.

Regurgitation that is repetitive, preceded by visible abdominal contractions and absent during sleep is rumination, not physiological reflux.

The alarm list is the boundary — reflux becomes disease when it causes troublesome symptoms or complications, and that is what those eight features detect.

Use the simplified criteria first in routine practice, and this score when they fall short but suspicion persists — more sensitive, at the cost of being far longer.

Complementary and often needed together — this score penalises a drug history by 4 points, and RUCAM quantifies how likely that drug really is to be responsible.

Upstream — the R factor classifies the biochemical pattern, which informs whether the ALP:AST term here will help or hurt.

Use the simplified score first and the revised original when it falls short — the first is more specific, the second more sensitive.

Frequently needed together — drug-induced liver injury is the principal mimic of autoimmune hepatitis, and this score has no drug term at all.

Different questions entirely — this score diagnoses autoimmune hepatitis, Child-Pugh grades the severity of established cirrhosis.

Different questions — BCLC allocates treatment across all stages, while Milan answers only whether a patient is within transplant criteria.

Child-Pugh is an input to BCLC, not an alternative to it — it supplies the liver function axis.

Sequential — LI-RADS establishes that a lesion is hepatocellular carcinoma, and BCLC then stages the confirmed disease.

Complementary — ALBI grades liver function more granularly than the binary preserved/end-stage split BCLC uses.

Sequential, not alternative — CLIF-SOFA (with the CANONIC definitions) establishes whether ACLF is present and its grade; CLIF-C ACLF then quantifies mortality risk in the patients who have it.

CLIF-C ACLF is the more accurate score in established ACLF, reducing prediction error by 19–28% against MELD and MELD-Na at every time point tested.

They describe different patient populations because APASL and EASL-CLIF define ACLF differently — pick the one matching the definition your unit uses.

Not suitable here — Child-Pugh grades chronic disease severity and was outperformed by CLIF-C ACLF at every time point in the derivation study.

Opposite directions and different timings — HAPS rules out a severe course at admission, BISAP predicts mortality within the first 24 hours.

Not comparable — Atlanta classifies severity retrospectively once 48 hours have passed, while HAPS answers a triage question at admission.

Both predict a non-severe course, but Glasgow-Imrie needs 48 hours and eight parameters where HAPS needs 30 minutes and three.

Sequential, not alternative — the R factor picks which RUCAM table to use, and RUCAM then scores causality.

Complementary and sequential — the R factor establishes that the pattern is hepatocellular, and Hy's law then asks whether that hepatocellular injury is dangerous.

Different diseases — Maddrey's grades severity in established alcohol-related hepatitis, while the R factor phenotypes a suspected drug injury.

Superseded. SAAG classifies ascites by portal hypertension with about 97% accuracy, while the exudate-transudate concept misclassified a substantial minority.

Different questions — SAAG asks why there is ascites, Child-Pugh grades how advanced the liver disease is once cirrhosis is established.

Complementary — SAAG is diagnostic, MELD-Na is prognostic and allocative, and neither substitutes for the other.

The fasting response is the better confirmatory test, and the osmotic gap is the better triage test — use them in that order.

Sequential — the Rome IV criteria are a diagnosis of exclusion, and the osmotic gap is part of the exclusion.

Complementary and prerequisite — Bristol describes stool form, and the osmotic gap requires a form (types 6–7) before it can be interpreted at all.

Different diseases with different criteria that share a name — pick by which organ is infected, not by which tool is to hand.

Superseded for diagnosis. The triad is specific but too insensitive to use as a gate, which is precisely why TG18 exists.

Complementary — gallstones cause both conditions, and a patient with gallstone pancreatitis and cholangitis needs grading under both systems.

Different diseases sharing a name — and the Grade II rules differ, one criterion here against two there, which is where they are most often confused.

Opposite ends of the same spectrum — Rome IV defines biliary-type pain without inflammation, TG18 defines the inflamed gallbladder.

Insufficient on their own — imaging is category C, one of three required categories, not the diagnosis.

PUCAI is the right instrument in children — it is non-invasive, validated in paediatric patients, and correlates with the Mayo score at r = 0.95.

Use PUCAI in children — Truelove and Witts was derived in adults in 1955 and its thresholds do not transfer to paediatric physiology.

SCCAI is the adult counterpart — same idea, non-invasive clinical scoring, but derived and validated in adults.

Complementary — UCEIS scores what the mucosa looks like, PUCAI scores how the child is, and a child can be in clinical remission with active mucosal disease.

SES-CD is the practical choice — it measures the same construct, correlates with CDEIS at r = 0.920, and is simple enough to use outside a trial.

Different situations entirely — Rutgeerts grades post-operative recurrence in the neoterminal ileum after ileocolonic resection; SES-CD grades endoscopic activity in intact bowel.

Complementary, not competing — CDAI measures how the patient feels and SES-CD measures what the bowel looks like, and the two correlate poorly.

Also complementary — Harvey-Bradshaw is a simplified clinical index and carries the same disconnect from mucosal appearance that CDAI does.

Use the King's criteria for paracetamol-induced failure and consider MELD for non-paracetamol failure — the meta-analysis is explicit that MELD should not replace the criteria in paracetamol cases.

Different patients entirely — the King's criteria are for acute liver failure in a previously healthy liver, CLIF-SOFA for organ failure in established cirrhosis.

The main European alternative, built around factor V and age rather than pH and creatinine; neither has been shown clearly superior, and the King's criteria are more widely used.

Not comparable — Child-Pugh grades chronic liver disease severity and has no role in acute liver failure.

LI-RADS decides whether a lesion is hepatocellular carcinoma; Milan decides whether the patient can be transplanted for it.

Complementary halves of the same decision — what the tumour is, and what the liver can tolerate.

Defines much of the at-risk population that LI-RADS is validated in, and constrains what can be done about an LR-5 finding.

Superseded. Savary-Miller mixed mucosal breaks with strictures and Barrett's oesophagus in a single scale, which made it unreproducible.

Complementary — LA grades the erosions reflux causes, Prague describes the columnar metaplasia it can produce, and both may be reported from one endoscopy.

Mutually exclusive by definition — functional heartburn requires the absence of erosive oesophagitis, so any LA grade rules it out.

Maddrey's DF decides who starts corticosteroids at admission; the Lille model decides who should stop them at day 7 — they are sequential steps in one pathway, not competing scores.

ABIC grades baseline risk into three tiers at admission while Lille measures response at day 7, and using them together predicts survival better than either in isolation.

GAHS predicts at admission who is likely to benefit from corticosteroids; Lille confirms at day 7 whether that prediction held for the individual patient in front of you.

Not competitors — Maddrey's DF decides whether to start steroids, and the Lille score, calculated after a week of treatment, decides whether to continue them.

GAHS was derived to correct Maddrey's DF omission of renal function and white cell count, and the two are often used together rather than as substitutes.

UCEIS is the better endoscopic instrument — it scores three features separately with defined descriptors, where the Mayo endoscopic subscore compresses everything into one four-point judgement.

They are complementary, not alternatives: Mayo measures how active the disease is now, Montreal records how extensive it is — and extent determines surveillance timing and route of therapy.

Different diseases: Mayo is for ulcerative colitis, Harvey-Bradshaw for Crohn's disease. Neither is validated in the other.

MEFIB is FIB-4 plus MRE — use FIB-4 alone as the cheap first-line rule-out, and add MRE to form MEFIB when you need a high-confidence rule-in for significant fibrosis without biopsy.

Both select candidates for NASH fibrosis therapy, but MEFIB uses MRE and reached a higher positive predictive value head-to-head, while FAST uses the cheaper, more available FibroScan — accuracy versus access.

Both are MRI-based, but they target different things — MAST estimates at-risk NASH (activity plus fibrosis) while MEFIB rules significant fibrosis in or out — so the choice follows whether the question is disease activity or fibrosis stage.

MELD 3.0 has superseded MELD-Na for US allocation and is the one to use for current listing decisions; MELD-Na remains relevant for comparability with older literature and in jurisdictions that have not adopted the update.

Use MELD 3.0 for transplant priority and prognosis, Child-Pugh whenever guidance is written in classes — the two are not substitutes and cannot be converted.

Use MELD-XI instead when the patient is anticoagulated, since MELD 3.0 still includes INR and is therefore still inflated by warfarin or a direct oral anticoagulant.

FIB-4 alone is the correct first-line test and this calculator computes it identically — the difference is that the composite also tells you what to do with the answer, and applies the age-65 cut-off shift automatically.

FAST answers one question — is this at-risk MASH — and answers it well; the composite includes FAST unchanged and places it alongside the fibrosis and portal hypertension questions that FAST does not address.

The NAFLD Fibrosis Score is corroboration, not a first-line test — it needs albumin and BMI that FIB-4 does not, and its indeterminate zone is wider.

Non-invasive testing has replaced biopsy for most staging decisions; biopsy remains useful when the tests are discordant or indeterminate and the answer would change management.

MELD 3.0 has superseded MELD-Na for US allocation — if you are asking about listing priority today, MELD 3.0 is the current formula.

Use MELD-Na for prognosis and transplant priority, and Child-Turcotte-Pugh for anything written in terms of its classes — drug dosing, trial eligibility, and procedural guidance are still expressed as class A/B/C.

Switch to MELD-XI when the patient is anticoagulated — it excludes INR, which is the variable that anticoagulation corrupts.

Use MELD-Na as the default in a non-anticoagulated cirrhotic patient, and MELD-XI only when anticoagulation makes the INR uninterpretable — MELD-XI trades a small amount of discrimination for freedom from a corrupted input.

MELD-XI and UKELD both depart from standard MELD but in opposite directions — MELD-XI removes a variable to survive a corrupted input, while UKELD adds sodium and recalibrates to a specific national waiting list.

Milan is the ceiling Metroticket was built to extend — morphology alone versus morphology priced by biology.

Both use AFP, for opposite purposes — one to find a tumour, the other to judge one already found.

Complementary halves of the transplant decision — what the tumour is, and what the liver can tolerate.

UCSF widens the size limits and reported 5-year survival of 75.2%, but Milan remains the reference standard because the expansion rests on a much smaller and single-centre evidence base.

Up-to-seven shows that the relationship between tumour burden and survival is continuous rather than a threshold — but its headline figure applies only to patients without microvascular invasion, which cannot be known before transplantation.

Two halves of one assessment — Milan describes the tumour and says nothing about the liver, ALBI describes the liver and says nothing about the tumour.

Adding alpha-fetoprotein to size and number outperformed Milan for predicting recurrence, and France allocates on that basis — evidence that a biomarker captures biology imaging misses.

Montreal supersedes Vienna and should be used instead — the changes fixed phenotypes Vienna described incorrectly rather than merely coarsely.

Paris is the paediatric version and should be used for childhood-onset disease — Montreal's single A1 category is too coarse for a population in which age of onset predicts phenotype.

Not alternatives — Montreal records what the disease is and where it is, while the activity indices record how it is behaving today, and ulcerative colitis management needs both.

Complementary — Montreal fixes the Crohn's phenotype in the record, the activity indices track the disease week to week, and treatment decisions draw on both.

Same chapter, same mechanism, opposite treatment — CAPS needs a neuromodulator added, narcotic bowel syndrome needs the opioid removed.

Both are opioid complications and they coexist constantly, but one is a peripheral motility effect and the other a central pain effect — with opposite implications for continuing the drug.

The differential that matters most, and the reason Rome IV requires two of three patterns rather than one — labelling genuinely under-treated pain as hyperalgesia causes real harm.

They are the reference and its surrogate — the NAS is read from the biopsy that the blood-based FNI is trying to predict, so use FNI to decide who needs a biopsy and the NAS to score the biopsy once taken.

Orthogonal measurements — the NAS grades activity on biopsy while FIB-4 estimates fibrosis from blood, so they capture different axes of the same disease and neither substitutes for the other.

The SAF score reports activity as ballooning plus inflammation only (0–4) and keeps steatosis and fibrosis as separate axes — arguably a cleaner separation than the NAS, which folds steatosis into the activity total.

FIB-4 is the better first-line test — it matched or beat the NFS on discrimination in head-to-head comparison and needs no BMI or albumin, making it usable on a routine blood panel alone.

BARD is simpler and matches the NFS on ruling advanced fibrosis out, but it discriminates less well overall and spares far fewer biopsies — the NFS is the more informative of the two.

They answer sequential questions, not the same one — the Fatty Liver Index predicts whether fat is present in the liver, while the NAFLD Fibrosis Score predicts whether that fat has caused advanced scarring.

The condition this must be separated from, because the treatments are opposite — laxatives for one, no laxatives for the other.

Both use developmental rather than chronological age, and both are under-disclosed — but the adult criteria do not separate retentive from nonretentive.

The adult evacuation disorders, which sit upstream of retentive rather than nonretentive incontinence.

They are territory-matched siblings: Glasgow-Blatchford identifies low-risk upper GI bleeds for discharge, Oakland does the same job for lower GI bleeds — use the one that matches the suspected source.

Different endpoints: Oakland answers 'can this lower GI bleed go home?', while ABC answers 'what is this patient's 30-day mortality?' across both upper and lower bleeding — pick the score whose question matches the decision.

Identical symptom items, different trigger and no duration rule — and Rome IV asks research studies to keep them apart while conceding they overlap in practice.

Different opioid complication entirely — one is constipation, the other is opioid-induced worsening of abdominal pain, and they can coexist.

Opioids impair evacuation as well as transit, so a patient can have both — and the evacuation component will not respond to opioid antagonists alone.

The presence or absence of retention decides it, and getting it wrong means giving laxatives to a child who has no stool to shift.

Rome IV settles the overlap explicitly — H3a requires that criteria for IBS are insufficient, so IBS takes precedence when both could apply.

The organic diagnosis these criteria must never mask, and the discriminators are almost all historical or on examination rather than in the stool pattern.

Nearly identical presentation in adolescents — the discriminators are exposure, hot bathing, and response to sustained cessation.

The same symptoms in a different temporal shape — episodic with full recovery, versus continuous.

Same family of paroxysmal disorders, differing in which symptom dominates — vomiting or pain.

Same subtypes, a third of the frequency bar, and an extra clause in the pain criterion to keep IBS out.

The boundary Rome IV wrote into the symptom itself — pain related to defecation is IBS, pain unrelated to it is dyspepsia.

Episodic and incapacitating with long well intervals, versus frequent and grumbling — the temporal shape separates them.

Shorter duration, lower frequency, one association instead of two, and a constipation clause with no adult equivalent.

The distinction Rome IV built a prospective test for — treat the constipation and see whether the pain remains.

The residual category that exists for children whose pain fits none of the three defined disorders, IBS included.

The adult chapter merged these two into one syndrome; the paediatric chapter deliberately kept them apart.

Episodic with complete wellness in between, versus continuous — the question is what happens between episodes.

Timing relative to meals is the boundary — postprandial nausea belongs to dyspepsia, not to functional nausea.

Same mechanism and same treatment; the paediatric criteria use two months rather than three and add an infant version built on observation.

Effortless in both — but rumination has visible preparatory contractions, stops when the infant is engaged, and never occurs in sleep.

Rome IV explicitly excludes rumination when diagnosing functional vomiting — retching is the dividing line.

Same sphincter, entirely different evidential bar — the biliary disorder needs biliary pain plus one marker, the pancreatic one needs documented pancreatitis plus three further investigations.

Not a competing diagnosis but the population these criteria are applied within — and most of that population turns out to have something other than a sphincter problem.

Different questions entirely — Atlanta grades the severity of an episode, these criteria ask why the episodes keep happening.

Different findings in the same organ — LA grades erosive oesophagitis, Prague describes columnar-lined oesophagus, and both may be reported from one endoscopy.

Superseded. A single length loses the distinction between the circumferential segment and the tongues, which vary independently.

Both standardise endoscopic description rather than compute risk, but for different diseases — Prague for Barrett's, EREFS for eosinophilic oesophagitis.

PELD and adult MELD-Na are scaled to be compared but are not built from the same variables — PELD swaps creatinine for albumin, growth failure and infancy, and has been shown to under-rank paediatric mortality relative to the adult scale.

Child-Pugh grades cirrhosis severity in broad classes and was never designed for children or for allocation; PELD is the paediatric waitlist instrument and is built from objective, verifiable variables for exactly that reason.

BISAP is the only one of the two available when the triage decision is made; Ranson is the more sensitive once 48 hours have passed, so the sequence is BISAP on day one and Ranson to confirm at 48 hours — not a choice between them.

Glasgow-Imrie asks for eight variables instead of eleven and reaches a comparable answer, which is why it displaced Ranson in UK practice — but it was derived to be completed at 48 hours too, so it solves the data burden rather than the timing problem.

They measure different things and neither substitutes for the other — Ranson grades the physiological insult over 48 hours, CTSI grades the anatomical damage on imaging, and a patient can score badly on one and well on the other.

APACHE II can be scored on day one and repeated daily, which Ranson cannot, but it needs a dozen variables and was built for general intensive care — in acute pancreatitis specifically it has not outperformed Ranson.

Use Glasgow-Blatchford at triage to decide who can avoid admission, and Rockall after endoscopy to gauge mortality risk — they answer different questions and neither substitutes for the other.

AIMS65 and pre-endoscopic Rockall serve the same triage moment and perform comparably for mortality; AIMS65 has the practical edge of being entirely lab- and mental-status-based, with no shock or comorbidity category to judge.

Identical except for the symptom-reflux association, and that single difference reverses the advice on acid suppression.

GORD has abnormal acid exposure; reflux hypersensitivity has a normal amount of reflux that the oesophagus over-reports.

Reflux hypersensitivity can present as chest pain, so the two overlap in symptom — the separator is again the reflux monitoring.

Not alternatives — Rome IV establishes the diagnosis and Bristol supplies the subtype, so the Rome IV assessment is incomplete without stool form.

Rome IV is the current standard and is deliberately narrower — a patient meeting Rome III may not meet Rome IV, and that is by design rather than a defect.

A positive Rome IV diagnosis with targeted testing is the guideline-endorsed strategy; routine colonoscopy in young patients without alarm features is explicitly not recommended.

Expert opinion remains the practical reference standard and RUCAM tends to score lower — the two agree only moderately, which is a documented limitation rather than a scoring error.

The R ratio classifies the pattern of injury; it says nothing about whether a drug caused it, and using it as though it did is a category error.

Complementary and frequently confused — RUCAM asks whether the drug caused the injury, Hy's law asks whether the injury is likely to be dangerous.

Naranjo is a general adverse-drug-reaction instrument; RUCAM is liver-specific and is what hepatology guidelines and regulators expect for suspected DILI.

The commonest misdiagnosis — rumination brings up recognisable, non-acidic food within minutes of eating, and does not respond to acid suppression because acid is not the mechanism.

Mutually exclusive — Rome IV requires rumination to be excluded before chronic nausea and vomiting syndrome can be diagnosed, and the separator is retching.

Both produce post-prandial upper GI symptoms, but rumination brings food up within minutes with no retching, while gastroparesis is defined by delayed emptying and typically involves nausea and vomiting.

They disagree by design — Harvey-Bradshaw measures how the patient feels and Rutgeerts measures what the anastomosis looks like, and in the first year after surgery the second is far ahead of the first.

The modification adds information about where the lesions are but has not displaced the original — trial literature still reports i0–i4, so record both.

Different anatomical questions — SES-CD scores Crohn's activity across five colonic segments, while Rutgeerts scores one specific site after one specific operation.

SAFE was purpose-built to beat FIB-4 in primary care — it discriminates significant fibrosis better in the general population and at age extremes, and leaves fewer indeterminate results — at the cost of three extra inputs (BMI, diabetes, globulin).

They share most inputs and both target advanced/significant fibrosis, but SAFE swaps albumin for globulin, keeps age continuous, and was validated for primary-care case-finding with a mortality link, making it the more modern general-population tool.

Different endpoints — SAFE estimates significant fibrosis (≥ F2), FNI estimates at-risk NASH (activity plus fibrosis) — so choose the score whose target matches the decision at hand.

They address different moments: EVendo predicts, before endoscopy, whether varices needing treatment are likely to be present; Sarin classifies gastric varices already seen so as to guide treatment.

Oesophageal varices are stratified mainly by size and red signs, whereas gastric varices are stratified by location using Sarin — because for gastric varices location, not size, is the dominant driver of both risk and treatment.

The SCCAI needs no endoscopy and is built for repeated, even patient-completed, monitoring; the Mayo score includes an endoscopy subscore and is the more common trial instrument for defining response and remission.

Use the SCCAI to grade and track activity across the mild-to-moderate range in outpatients, and the Truelove and Witts criteria to make the binary admission decision in an acute severe flare.

Pain is the divide — functional diarrhoea of childhood is painless by definition, and IBS requires abdominal pain.

Growth is the discriminator — coeliac disease that presents with chronic diarrhoea in a preschool child almost always disturbs the growth trajectory.

The infectious mimic worth remembering, and the one where a stool test is genuinely indicated when the picture does not quite fit.

Same question, same day, different shape — binary versus graded, and only Ho sees colonic dilatation.

Truelove and Witts gets the patient admitted; Travis decides what happens on day 3.

Endoscopic severity at one moment against clinical trajectory over three days — related but not interchangeable.

Use the Truelove and Witts criteria to decide who needs admitting for acute severe colitis, and the SCCAI to track outpatient activity over time — they answer different questions and are not interchangeable.

Truelove and Witts classifies an acute attack for the admission decision; the Mayo score quantifies activity and endoscopic healing for treatment monitoring and trials.

The UCEIS is the more reproducible endoscopic measure because every level is defined; the Mayo endoscopic subscore is simpler and more familiar but its single 0–3 judgement disagrees more often between endoscopists.

The UCEIS measures mucosal inflammation at endoscopy; the SCCAI measures symptoms without endoscopy — they are complementary, and the mismatch between them is often the clinically useful finding.

In UK elective waiting-list data UKELD predicted list mortality better than MELD-Na, which is why the UK uses it — but MELD-Na remains the relevant score in US-based allocation, and the two are not interchangeable.

Child-Pugh remains a useful bedside grade of cirrhosis severity, but UKELD is the instrument that determines UK transplant listing eligibility because it is continuous, objective and calibrated to waiting-list mortality.

IBS is the first category to check and the commonest reason this label does not apply — the discriminator is recurrent abdominal pain meeting the frequency and characteristic requirements.

Different kinds of residual — IBS-U is for a patient who meets IBS criteria but has no dominant stool pattern; this category is for a patient who does not meet IBS criteria at all.

The category most often narrowly missed, because it requires bloating to *predominate* as well as occur weekly — and predominance is a judgement.

Use VOCAL-Penn for the surgical question and MELD-Na for liver disease severity — they answer different questions, and MELD-Na was never built to account for the operation.

VOCAL-Penn discriminated substantially better for post-operative mortality — Child-Turcotte-Pugh had the weakest performance of every tool compared (C-statistic 0.682 versus 0.859).

VOCAL-Penn outperformed it in the derivation cohort, and the Mayo score's specific failure was calibration — it overestimated risk across the whole spectrum.

Not interchangeable — West Haven grades the specific syndrome of hepatic encephalopathy including its early cognitive features, while the Glasgow Coma Scale measures depth of unconsciousness and is blind to everything above it.

They cover the range West Haven cannot see — a patient graded 0 may still have measurable cognitive impairment, and only testing will show it.

CLIF-SOFA consumes the West Haven grade rather than competing with it — the grade is the input, and grade III or above is what counts as cerebral organ failure.