Truelove and Witts Severity Interpreter
Truelove and Witts Severity Interpreter
1955, and still the definition of an acute severe attack. It does not add up to anything: six or more bloody stools a day PLUS any one systemic feature. Six stools alone is not severe.
Truelove and Witts criteria
Stools + systemic features → gradeSeven blood-stained stools in 24 hours, pulse 96, temperature 37.2 °C, haemoglobin 110 g/L, ESR 24 mm/h
A conjunction, not a sum
AND at least one of
pulse above 90 /min · temperature above 37.8 °C (37.5 °C in some sources) · haemoglobin below 105 g/L · ESR above 30 mm/h
ECCO’s reproduction of the full grading: bloody stools fewer than 4 mild · 4–6 moderate · 6 or more severe
- there is no total
- the criteria do not add up and there is no score. Four systemic features present is the same verdict as one. Anything that reports a Truelove and Witts “score” has invented it, and the published criteria carry no weighting that would justify one
- the stool count is a gateway, not a point
- without 6 or more blood-stained stools the systemic features do not make an attack severe by these criteria, however abnormal they are. Six bloody stools with a normal pulse, temperature, haemoglobin and ESR is NOT a severe attack here
- two printed disagreements
- temperature above 37.8 °C (ECCO-ESGAR; Jain 2018) versus above 37.5 °C (NHS Borders; the Montreal S3 grade). Stool count 6 or more (ECCO-ESGAR; Jain 2018) versus more than 6 (NHS Borders). This page uses 6 or more and 37.8 °C, and flags the 37.5–37.8 °C window separately rather than resolving it silently
- CRP is not one of the four
- Truelove and Witts predate routine CRP. ECCO-ESGAR’s Table 3 adds a CRP column to the modern grading, and the day-3 Oxford criteria use CRP directly. If you are reading a CRP in an acute severe attack, the day-3 criteria are the instrument built for it
- a negative result is not reassurance
- beta-blockade and rate-limiting drugs hold the pulse below 90; the haemoglobin lags behind acute blood loss; and the ESR rises slowly and has an age-dependent upper limit. All three push a genuinely severe attack below the criteria
Worked example
Seven blood-stained stools in 24 hours, pulse 96, temperature 37.2 °C, haemoglobin 110 g/L, ESR 24 mm/h
Seven blood-stained stools is 6 or more, so the gateway condition is met
Pulse 96 is above 90 → one systemic feature present. Temperature 37.2 °C, haemoglobin 110 g/L and ESR 24 mm/h are all on the normal side of their thresholds
One feature is enough. The criteria are a conjunction of the stool count with ANY ONE systemic feature and there is no total — this patient's verdict would be identical with all four features present
Now change one thing: with a pulse of 88 instead of 96, and nothing else altered, this patient has seven bloody stools and no systemic feature and does NOT meet the criteria. That single number is the difference, which is why a rate-limited pulse matters
The next question is not this one. Reassessment on the third day of treatment is what the day-3 criteria were derived for, and they use the stool count and the CRP
The criteria for a severe attack
| Component | Threshold | Role |
|---|---|---|
| Blood-stained stools per 24 h | 6 or more | GATEWAY. Required. Without it the criteria are not met. |
| Pulse | Above 90 /min | Any ONE of these four is enough. |
| Temperature | Above 37.8 °C (37.5 °C in some sources) | Any ONE of these four is enough. |
| Haemoglobin | Below 105 g/L (10.5 g/dL) | Any ONE of these four is enough. |
| ESR | Above 30 mm/h | Any ONE of these four is enough. |
Where the sources disagree, and what it changes
| Item | ECCO-ESGAR / Jain 2018 | NHS Borders / Montreal S3 | The patient it moves |
|---|---|---|---|
| Stool count | 6 or more | More than 6 | Exactly 6 bloody stools: severe on the left, not on the right. |
| Temperature | Above 37.8 °C | Above 37.5 °C | 37.6–37.8 °C: a systemic feature on the right, not on the left. |
| Haemoglobin | Below 105 g/L | Below 10.5 (unit not stated) | None — the same number in two unit systems. |
| ESR | Above 30 mm/h | Above 30 (unit not stated) | None. |
| CRP | Added as a column in ECCO’s modern table | Not in the original four | Everyone: a raised CRP is not a Truelove and Witts criterion. |
A 1955 trigger that never became a score
Truelove and Witts defined a severe attack of ulcerative colitis in the final report of their cortisone trial in 1955, and the definition has outlived almost everything else from that paper. It is still what admits a patient, still what starts intravenous corticosteroid, and still what defines the entry population of acute severe colitis trials seventy years later.
The important structural point is that it is not a score and was never meant to be one. The criteria are a conjunction: six or more blood-stained stools in 24 hours, PLUS at least one of a pulse above 90, a temperature above 37.8 °C, a haemoglobin below 105 g/L and an ESR above 30 mm/h. There is no total, no weighting and no gradient. Four features present is the same verdict as one. Six bloody stools with a normal pulse, temperature, haemoglobin and ESR does not meet the definition at all, and that is the single most commonly misread thing about it — the stool count is a gateway, not a point.
Two of the thresholds are printed differently by sources a clinician is likely to be reading side by side. ECCO-ESGAR and Jain’s prospective Indian cohort both give 6 or more bloody stools and a temperature above 37.8 °C. The NHS Borders guideline gives more than 6 stools and a temperature above 37.5 °C, and the Montreal classification’s severe grade also uses 37.5 °C. So a patient with exactly six bloody stools, or a temperature of 37.6 °C, is severe under one document and not under another. This page implements 6 or more and 37.8 °C and returns a separate reading for the disputed temperature window, rather than quietly choosing. Note also that CRP is not one of the four features: it postdates the criteria, ECCO’s modern table adds it as a column, and the instrument that actually uses CRP in this setting is the day-3 reassessment.
Which is where the modern layer sits, and it is the most useful thing this page can point at. Meeting Truelove and Witts starts treatment; it does not predict the outcome of that treatment. The day-3 Oxford criteria do. In 51 consecutive episodes of severe colitis in 49 patients at the John Radcliffe Hospital, all admitted on these criteria, Travis and colleagues found that on the third day of intravenous corticosteroid either more than 8 stools, or a stool frequency of 3 to 8 together with a CRP above 45 mg/L, identified a group of whom 85% underwent colectomy during that admission. Naming that reassessment, with its cohort, is more useful than anything the admission criteria themselves can say on day 3. For measuring activity outside an acute attack the Mayo score is the trial instrument, and the CRP unit converter and age-adjusted ESR upper limit are the inflammatory markers these criteria and their successor both rest on. A score is not a diagnosis and a figure from a cohort is not a probability for one patient. This states what the number meant in a named study; the clinician in front of the patient decides what follows. Thresholds here are the published ones; reference intervals and assay units are method- and laboratory-dependent and your own laboratory’s interval takes precedence.
Frequently asked questions
Does the Truelove and Witts index give a score?
No, and that is the point. It is a conjunction: six or more blood-stained stools in 24 hours plus at least one systemic feature. There is no total and no weighting, so four features present gives the same verdict as one. Anything reporting a Truelove and Witts score has invented it.
Is six bloody stools a day enough to be severe?
No. The stool count is the gateway condition and at least one systemic feature is also required — pulse above 90, temperature above 37.8 °C, haemoglobin below 105 g/L, or ESR above 30 mm/h. Six or more bloody stools with all four of those normal does not meet the criteria.
Is the temperature threshold 37.5 or 37.8 °C?
Both are in print. ECCO-ESGAR and Jain’s prospective study give above 37.8 °C; the NHS Borders guideline and the Montreal severe grade give above 37.5 °C. A patient at 37.6 °C has a systemic feature under one and not under the other. This page uses 37.8 °C and flags the disputed window separately.
Why is CRP not one of the criteria?
Because the criteria are from 1955 and predate routine CRP measurement; the four systemic features are pulse, temperature, haemoglobin and ESR. ECCO-ESGAR’s modern severity table adds a CRP column, and the Oxford day-3 criteria use CRP above 45 mg/L directly. A raised CRP on admission is not a Truelove and Witts criterion.
What happens after the criteria are met?
This page does not say, and deliberately so. What the literature does say is what the numbers predicted: in the 51 Oxford episodes, about a quarter came to colectomy during that admission, and on the third day of intravenous corticosteroid either more than 8 stools or 3 to 8 stools with a CRP above 45 mg/L identified a group of whom 85% did. That day-3 reassessment is a separate calculation.
Related calculators
References
- Jain S, Kedia S, Bopanna S, et al. Are Truelove and Witts criteria for diagnosing acute severe colitis relevant for the Indian population? A prospective study. Intest Res. 2018;16(1):69–74.
- Sturm A, Maaser C, Calabrese E, et al. ECCO-ESGAR guideline for diagnostic assessment in IBD part 2: IBD scores and general principles and technical aspects. J Crohns Colitis. 2019;13(3):273–84. doi:10.1093/ecco-jcc/jjy114
- NHS Borders. Acute severe colitis — gastroenterology clinical guideline. rightdecisions.scot.nhs.uk.
- Travis SPL, Farrant JM, Ricketts C, et al. Predicting outcome in severe ulcerative colitis. Gut. 1996;38(6):905–10 (abstract).
- Glinkowski S, Marcinkowska D. Ulcerative colitis: assessment of disease activity based on contemporary scales. Nowa Medycyna. czytelniamedyczna.pl.
Not medical advice. For healthcare professionals and education. Reference intervals vary by laboratory and assay — always use your own laboratory's. Never base a dose or a treatment decision on this page alone. Full disclaimer at calcengines.com/disclaimer/