About the Simple Endoscopic Score for Crohn's Disease (SES-CD)
Score four descriptors — ulcer size, ulcerated surface, affected surface and narrowing — from 0 to 3 in each of five segments (ileum, right colon, transverse colon, left colon, rectum), then add them up. A total of 0–2 is endoscopic remission, 3–6 mild, 7–15 moderate and 16 or above severe. The published range is 0–56 rather than the arithmetic 0–60, because only one segment can carry an impassable stenosis. SES-CD was built to replace CDEIS, which measures the same thing but is too slow for routine use; the two correlate at r = 0.920.
Formula
SES-CD = Σ over 5 segments of (ulcer size + ulcerated surface + affected surface + narrowing)
Segments: ileum · right colon · transverse colon · left colon · rectum
Each descriptor scored 0–3, so each segment contributes 0–12- ulcer size
- 0 none · 1 aphthous 0.1–0.5 cm · 2 large 0.5–2 cm · 3 very large over 2 cm.
- ulcerated surface
- 0 none · 1 under 10% · 2 from 10 to 30% · 3 over 30%.
- affected surface
- 0 unaffected · 1 under 50% · 2 from 50 to 75% · 3 over 75%.
- narrowing
- 0 none · 1 single, passable · 2 multiple, passable · 3 cannot be passed.
- The published maximum is 56, not the arithmetic 60. Only one segment can carry a stenosis that cannot be passed, since the endoscope stops there — so the narrowing descriptor tops out at 3 + (2 × 4) = 11 across the five segments, rather than 15.
- A segment that was not reached should be recorded as not assessed, not as 0. Scoring an unintubated ileum as normal is the commonest way a SES-CD is silently understated.
- Affected surface should normally be at least as high as ulcerated surface in the same segment, because ulceration is a subset of affected mucosa. A lower affected score is usually a data-entry error.
- The score treats an inflammatory and a fibrotic stricture identically. That distinction has to come from imaging or from the clinical picture, not from this number.
- The severity bands (0–2, 3–6, 7–15, ≥16) were proposed after the original derivation rather than in Daperno's 2004 paper itself, and are convention rather than a validated cut-point analysis.
Interpreting the result
Read the total against the bands, but read the change against the previous examination, because that is what actually drives decisions. A SES-CD of 2 or below is endoscopic remission and the STRIDE-II long-term target; 3–6 is mild, 7–15 moderate, and 16 or above severe. A score of 7 or above has been associated with a higher risk of disease progression, which is why that boundary tends to prompt escalation even in a patient who feels well. Two cautions matter more than the band itself. First, the per-segment distribution carries information the total hides: an isolated ileal score of 10 and a score of 10 spread across the colon are different diseases with different management. Second, the score says nothing about what was not seen — a partial examination produces a lower number with no indication that anything was missed, so the segments reached must be documented alongside the score.
| Score | Band | What it means | Action |
|---|---|---|---|
| 0–2 | Endoscopic remission | The STRIDE-II long-term treatment target. Associated with better long-term outcomes than symptomatic remission alone | Continue current therapy; monitor between endoscopies with faecal calprotectin |
| 3–6 | Mild endoscopic activity | Residual inflammation short of the remission target | Read against the previous score — a 5 falling from 18 differs from a 5 rising from 1; optimise current therapy |
| 7–15 | Moderate endoscopic activity | A SES-CD of 7 or above has been associated with a higher risk of disease progression | Consider escalation even where symptoms are mild; distinguish inflammatory from fibrotic narrowing before doing so |
| ≥ 16 | Severe endoscopic activity | Extensive ulceration and a high burden of active disease | Escalate therapy; a patient who feels well in this band is a common and important finding, not a contradiction |
What the SES-CD needs (5 inputs)
- Size of ulcers
- Per segment: 0 none, 1 aphthous ulcers 0.1–0.5 cm, 2 large ulcers 0.5–2 cm, 3 very large ulcers over 2 cm. Judged on the largest ulcer in that segment.
- Ulcerated surface
- Per segment: 0 none, 1 under 10%, 2 from 10 to 30%, 3 over 30%. The proportion of the segment's surface covered specifically by ulceration.
- Affected surface
- Per segment: 0 unaffected, 1 under 50%, 2 from 50 to 75%, 3 over 75%. This covers all disease-related change — erythema, oedema, friability, nodularity — not only ulcers, so it is normally at least as high as the ulcerated surface score.
- Presence of narrowing
- Per segment: 0 none, 1 single and passable, 2 multiple and passable, 3 cannot be passed. This descriptor makes no distinction between an inflammatory and a fibrotic stricture, which matters because only the first responds to medical therapy.
- Segments assessed
- Ileum, right colon, transverse colon, left colon (descending and sigmoid), and rectum. A segment that was not reached must not be recorded as 0 — that value means examined and normal.
What it returns
- SES-CD total
- The sum of all four descriptors across all five segments. Published range 0–56.
- Per-segment subtotals
- Each segment's contribution, 0–12. Useful because disease distribution changes management independently of the total — an isolated ileal score of 10 is a different problem from 10 spread thinly across the colon.
- Severity band
- Remission (0–2), mild (3–6), moderate (7–15) or severe (16+).
How it is calculated
Daperno and colleagues set out to reproduce CDEIS with fewer moving parts. They started from a set of candidate endoscopic parameters, tested how reproducibly each could be scored by pairing the endoscopist with an independent observer across 71 examinations, and kept only those with excellent agreement — the resulting kappa coefficients ran from 0.791 to 1.000. Multiple linear regression on 70 patients then identified the simplest combination that tracked both CDEIS and the CDAI, which turned out to be the straight sum of four descriptors across five segments with no weighting and no arithmetic beyond addition. That simplicity is deliberate: CDEIS requires computing affected and ulcerated lengths and dividing by the number of segments explored, which is precisely why it stayed in trials. The simplified score was then validated prospectively in a separate cohort of 121 patients, where it correlated with CDEIS at r = 0.920 and also tracked clinical parameters and C-reactive protein.
Facts & figures
| Descriptor | 0 | 1 | 2 | 3 |
|---|---|---|---|---|
| Size of ulcers | None | Aphthous, 0.1–0.5 cm | Large, 0.5–2 cm | Very large, over 2 cm |
| Ulcerated surface | None | Under 10% | 10–30% | Over 30% |
| Affected surface | Unaffected | Under 50% | 50–75% | Over 75% |
| Narrowing | None | Single, passable | Multiple, passable | Cannot be passed |
Each segment contributes 0–12 and there are five segments, so the arithmetic ceiling is 60 — but the published maximum is 56, because a stenosis that cannot be passed stops the examination and so can only be scored once.
| Score | What it measures | Where it is used |
|---|---|---|
| SES-CD | Endoscopic severity of Crohn's disease across five segments | Routine practice and trials; the practical standard |
| CDEIS | The same construct, with lengths measured and divided by segments explored | Trials only — too slow for routine use |
| Rutgeerts score | Post-operative recurrence in the neoterminal ileum after ileocolonic resection | Only after resection; not interchangeable with SES-CD |
| CDAI | Symptoms, wellbeing and a haematocrit term — not mucosal appearance | Clinical activity; correlates poorly with endoscopy |
SES-CD and CDEIS correlate at r = 0.920 in the validation cohort, which is the basis for using the simpler score in place of the older one.
Evidence
Derivation and validation — Daperno et al.
2004 · n = 121Reproducibility of candidate endoscopic parameters was assessed across 71 examinations in which the endoscopist was paired with an independent observer. The score was then derived in 70 patients by multiple linear regression against CDEIS and CDAI, and prospectively validated in a separate cohort of 121 patients with Crohn's disease.
Interobserver agreement for all selected endoscopic variables was excellent, with kappa coefficients from 0.791 to 1.000. In the validation phase SES-CD correlated strongly with CDEIS (r = 0.920), and also correlated with clinical parameters and serum C-reactive protein.
Severity categorisation — Narula et al. (MM-SES-CD)
2022Analysis of clinical trial data developing a modified multiplier SES-CD, which weights segments and descriptors rather than summing them equally, and which restates the conventional SES-CD severity categories.
Supports the conventional categories of 0–2 remission, 3–6 mild, 7–15 moderate and ≥16 severe, while showing that equal weighting of all descriptors and segments loses information that a weighted version recovers.
Treatment targets — STRIDE-II
2021International consensus initiative of the International Organization for the Study of IBD, updating the formal treatment targets for Crohn's disease and ulcerative colitis.
Established endoscopic healing as a formal long-term target in Crohn's disease, with SES-CD as an accepted instrument for measuring it — the reason the score now appears in routine reports rather than only in trials.
How it compares
SES-CD vs CDEIS
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.
CDEIS was the only validated endoscopic index before SES-CD, but it requires estimating ulcerated and affected lengths in centimetres and dividing by the number of segments explored. That arithmetic is why it never left clinical trials. SES-CD replaces the measurements with four ordinal descriptors and the division with a plain sum, at very little cost in agreement with the original.
SES-CD vs Rutgeerts score
Different situations entirely — Rutgeerts grades post-operative recurrence in the neoterminal ileum after ileocolonic resection; SES-CD grades endoscopic activity in intact bowel.
After ileocolonic resection, the question is not how much disease is present overall but whether recurrence has begun at the anastomosis and how extensive it is, which Rutgeerts grades i0 to i4. Applying SES-CD in that setting misses the point of the examination, and applying Rutgeerts to unoperated bowel is meaningless. Use the one that matches the anatomy in front of you.
SES-CD vs CDAI
Complementary, not competing — CDAI measures how the patient feels and SES-CD measures what the bowel looks like, and the two correlate poorly.
CDAI is built from a symptom diary, wellbeing, extraintestinal features, antidiarrhoeal use, abdominal mass, haematocrit and weight. None of that inspects the mucosa, and a substantial proportion of patients in clinical remission by CDAI have active ulceration. STRIDE-II keeps both: symptomatic response as a short-term target and endoscopic healing as a long-term one.
SES-CD vs Harvey-Bradshaw Index
Also complementary — Harvey-Bradshaw is a simplified clinical index and carries the same disconnect from mucosal appearance that CDAI does.
Harvey-Bradshaw was designed as a simpler proxy for CDAI using five clinical items scored on a single day, and it correlates well with CDAI precisely because it measures the same thing. That means it inherits CDAI's weak relationship with endoscopic activity, so a low Harvey-Bradshaw index is not evidence of mucosal healing.
Pearls & pitfalls
- A segment that was not reached is not a segment that scored 0. Recording an unintubated ileum as normal is the commonest reason a SES-CD understates disease, and the score gives no signal that anything was missed.
- The published maximum is 56, not 60. Only one segment can carry an impassable stenosis, because the endoscope stops there.
- Affected surface should be at least as high as ulcerated surface in the same segment — ulcerated mucosa is a subset of affected mucosa. A lower affected score almost always means the two were transposed.
- The narrowing descriptor does not distinguish inflammatory from fibrotic stricture. Escalating medical therapy for a fibrotic stricture will not work, and the score cannot tell you which you are looking at.
- Every descriptor and every segment is weighted equally, so widespread mild change can outscore severe focal disease. Read the per-segment breakdown, not just the total.
- Symptoms track endoscopic activity poorly in both directions. A well patient with a SES-CD of 18 is a real and important finding; so is a symptomatic patient with a SES-CD of 1.
- This is not the Rutgeerts score. After ileocolonic resection, post-operative recurrence in the neoterminal ileum is graded with Rutgeerts, and the two are not interchangeable.
- The severity bands come from later convention rather than from Daperno's 2004 paper, so treat the boundaries as useful shorthand rather than as validated cut-points.
Critical actions
- Document which segments were actually examined, alongside the score. A SES-CD without that context is not comparable with any other SES-CD.
- Record the score in the endoscopy report itself rather than reconstructing it later from prose — the descriptors depend on judgements made at the time.
- Compare against the patient's previous SES-CD and act on the direction of change, not the absolute value alone.
- Where narrowing scored 1 or more, characterise the stricture with cross-sectional imaging before escalating medical therapy.
- Where the score is active but symptoms are absent, treat the score — this is the situation STRIDE-II's endoscopic target exists for.
- Where symptoms are marked but the mucosa is healed, look elsewhere: bile-salt malabsorption, fibrotic stricture, bacterial overgrowth or coexisting irritable bowel syndrome.
Why this score exists
The paper is unusually explicit that simplicity was the goal rather than a side effect. CDEIS already existed and was validated, so the problem was not measurement but adoption: it required computing ulcerated and affected lengths and dividing by the number of segments explored, and no one was going to do that at the end of a routine list. Daperno's group therefore selected parameters by reproducibility first, keeping only those two observers could agree on, and then took the simplest combination that still tracked CDEIS. The result has no weighting at all — every descriptor and every segment counts the same. That is a known compromise rather than an oversight, and it is exactly what the later modified multiplier version set out to address.
About the creator
First author, 2004 derivation and validation study
Led the development of the simplified endoscopic score intended to replace CDEIS in routine practice.
Co-author of the 2004 study, and an author of the earlier CDEIS work against which SES-CD was validated.
Co-author of the 2004 derivation and validation study.
Limitations
- Every descriptor and every segment carries equal weight, so extensive mild change can produce a higher total than severe focal disease. The modified multiplier version was developed specifically to address this.
- Gives no indication when the examination was incomplete. An unreached segment scored 0 lowers the total silently, which makes partial examinations non-comparable.
- Does not distinguish inflammatory from fibrotic narrowing, despite that distinction determining whether medical therapy can help.
- Assesses only bowel reachable by ileocolonoscopy. Proximal small bowel disease is invisible to it, and cross-sectional imaging or capsule studies are needed to see that.
- The severity bands are later convention rather than part of the original validation, and the boundaries have not been subjected to a formal cut-point analysis.
- Correlates poorly with symptoms in both directions, so it cannot be used as a proxy for how a patient feels, nor the reverse.
- Interobserver agreement was excellent among trained observers in the derivation study; agreement in unselected routine practice is likely to be lower, particularly for the affected-surface descriptor.
If you are the patient
The SES-CD is a score your gastroenterologist works out during a colonoscopy to describe how much active inflammation there is in your bowel, and where. They look at five sections of bowel and, in each one, judge four things: how big any ulcers are, how much of the surface is ulcerated, how much is affected in any way, and whether there is any narrowing. Each judgement scores 0 to 3, and adding them all together gives the final number. A score of 0 to 2 means the bowel has essentially healed, which is the goal of treatment; higher numbers mean more active inflammation. The most useful thing about it is comparison — the score from this colonoscopy set against the one before tells your team whether your treatment is working. It is worth knowing that this score and how you feel do not always agree. Some people feel well but still have significant inflammation, which is one reason these scopes are done even when things seem fine; others have troubling symptoms with a healed bowel, which points the team towards a different cause.
Frequently asked questions
What is the SES-CD?#
The Simple Endoscopic Score for Crohn's Disease: four descriptors (ulcer size, ulcerated surface, affected surface and narrowing) each scored 0–3 in five bowel segments, then summed. The published range is 0–56.
What SES-CD score is remission?#
0 to 2 is conventionally endoscopic remission, and it is the long-term treatment target set out in STRIDE-II. Some trials use a stricter definition requiring the complete absence of ulceration.
Why is the maximum 56 and not 60?#
Four descriptors × five segments × 3 points would be 60, but a stenosis that cannot be passed can only occur once — the endoscope stops there. So the narrowing descriptor tops out at 3 + (2 × 4) = 11 across the five segments rather than 15, giving 56.
What are the SES-CD severity categories?#
0–2 remission, 3–6 mild, 7–15 moderate and 16 or above severe. These categories were proposed after the original 2004 derivation rather than in it, so they are convention rather than validated cut-points.
How should a segment that was not reached be scored?#
As not assessed, never as 0. A 0 means the segment was examined and found normal. Recording an unintubated ileum as 0 understates the score with no indication that anything was missed, and makes the result non-comparable with a complete examination.
Is SES-CD the same as the Rutgeerts score?#
No. Rutgeerts grades post-operative recurrence in the neoterminal ileum after ileocolonic resection, on a scale of i0 to i4. SES-CD grades endoscopic activity in intact bowel. They are not interchangeable and apply to different patients.
How does SES-CD compare with CDEIS?#
They measure the same construct and correlated at r = 0.920 in the validation cohort. CDEIS requires measuring ulcerated and affected lengths and dividing by the number of segments explored, which kept it confined to clinical trials; SES-CD was built to be simple enough for routine reporting.
Can a patient feel well with a high SES-CD?#
Yes, and it is common. Symptoms and mucosal inflammation correlate poorly in Crohn's disease in both directions — which is precisely why endoscopic healing is a separate treatment target from symptomatic remission.
References
Original / primary reference
Severity categories and treatment targets
- Narula N, Pray C, Wong ECL, et al. Categorising Endoscopic Severity of Crohn's Disease Using the Modified Multiplier SES-CD [MM-SES-CD]. J Crohns Colitis. 2022;16(7):1011-1019.
- Turner D, Ricciuto A, Lewis A, et al. STRIDE-II: An Update on the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) Initiative of the International Organization for the Study of IBD (IOIBD). Gastroenterology. 2021;160(5):1570-1583.