Truelove & Witts Severity Index

Free Truelove and Witts calculator for UC: classify mild, moderate, or severe attack severity from bloody stool frequency, pulse, temperature, hemoglobin (g/dL), and ESR (mm/h). Educational use with bedside context.

Truelove & Witts severity index

Stool frequency with blood, heart rate, temperature, hemoglobin (g/dL), and ESR (mm/h, first hour)—per the classic ulcerative colitis attack severity schema.

Stool frequency (bowel movements per 24 h)

Predominantly bloody stoolsUncheck only if blood is not a dominant feature (classification will be flagged as less reliable).

Pulse

Severe if ≥90/min (with ≥6 bloody stools/day).

Temperature

Unit

Severe if ≥37.8°C (≥100°F) with ≥6 bloody stools/day.

Hemoglobin (g/dL)

Severe if <10.5 g/dL with ≥6 bloody stools/day.

ESR (mm/h, first hour)

Severe if >30 mm/h with ≥6 bloody stools/day.

Disclaimer: Truelove–Witts criteria are a historical clinical framework. They do not replace endoscopy, specialist IBD pathways, or individualized assessment—including pediatric populations, pregnancy, and patients on therapies that blunt inflammatory markers.

Truelove & Witts severity index (ulcerative colitis)

Original clinical definitions

Truelove and Witts stratified first attacks of ulcerative colitis using stool frequency with visible blood together with simple bedside and laboratory markers of systemic illness. The categories guide intensity of monitoring and therapy; modern practice also uses endoscopic scores (e.g. Mayo, UCEIS) and objective inflammation (CRP, fecal calprotectin), but these historical thresholds remain widely referenced.

Mild

Fewer than 4 bowel movements per day with blood
No systemic disturbance: pulse, temperature, hemoglobin, and ESR are in the "normal" columns of the original criteria (see below).

Severe

At least 6 bowel movements per day with blood
And at least one of: pulse ≥90/min, temperature ≥37.8°C (100°F), hemoglobin <10.5 g/dL, ESR >30 mm/h (first hour).

Moderate

Disease that does not meet mild or severe definitions—for example, 4–5 bloody stools per day, or ≥6 bloody stools without systemic toxicity, or <4 stools with any systemic abnormality.

Calculator logic (summary)

systemic = (HR ≥ 90) ∨ (T ≥ 37.8°C) ∨ (Hb < 10.5 g/dL) ∨ (ESR > 30)

Mild if stools < 4/day with blood and NOT systemic.
Severe if stools ≥ 6/day with blood AND systemic.
Moderate otherwise (including when bloody stool is not predominant—interpret with caution).

Limitations

Derived in an era before widespread biologics; thresholds are guides, not substitutes for clinical judgment.
ESR is nonspecific; CRP and calprotectin are often used in parallel today.
Extensive colitis vs proctitis may differ in stool counts; correlate with examination and endoscopy.

Reference

Truelove SC, Witts LJ. Cortisone in ulcerative colitis: final report on a therapeutic trial. Br Med J. 1955;2(4947):1041–1048.

Overview

The Truelove and Witts severity index is one of the earliest and most durable clinical frameworks for describing how ill a patient is during an ulcerative colitis (UC) flare. Developed in the era of corticosteroid trials, it was designed to separate patients who could reasonably be managed with oral therapy and outpatient follow-up from those whose illness had systemic features that implied higher short-term risk and a need for more intensive treatment and monitoring.

Although modern inflammatory bowel disease (IBD) practice now relies heavily on endoscopic severity scores (for example Mayo endoscopic subscore and the Ulcerative Colitis Endoscopic Index of Severity), acute phase reactants such as C-reactive protein, and fecal calprotectin, the Truelove–Witts categories remain widely cited because they translate quickly at the bedside: stool frequency with visible blood, vital signs, hemoglobin, and the erythrocyte sedimentation rate.

What the index is trying to capture

Ulcerative colitis activity is not defined by mucosal appearance alone. During an attack, two parallel problems often coexist:

Colonic inflammation and mucosal injury, which drives urgency, diarrhea, and hematochezia.
Systemic inflammatory burden, reflected by tachycardia, fever, anemia from ongoing blood and iron loss (and sometimes hemoconcentration early followed by dilution or loss), and laboratory markers such as elevated ESR.

The Truelove–Witts schema uses simple, widely available measures to approximate that second axis—systemic toxicity—alongside stool frequency as a proxy for colonic disease intensity. It does not specify extent of disease (proctitis versus pancolitis) directly; clinicians still integrate sigmoidoscopic or colonoscopic findings, distribution of symptoms, and prior disease pattern.

Definitions used in clinical teaching

Most educational summaries of Truelove–Witts describe three strata: mild, moderate, and severe. The boundaries are deliberately coarse; they were created to support cohort comparisons and treatment decisions in hospitalized populations, not to replace individualized assessment.

Mild ulcerative colitis (Truelove–Witts)

Mild disease is typically described as fewer than four bowel movements per day that contain visible blood, together with absence of meaningful systemic disturbance. In the classical framing, “absence of systemic disturbance” corresponds to normal or near-normal heart rate, temperature, hemoglobin, and ESR relative to the published cutoffs used for severe disease.

Clinically, patients in this band often have rectal bleeding and increased stool frequency but remain hemodynamically stable, afebrile or only modestly unwell, and without profound anemia or markedly elevated inflammatory markers by the ESR criterion. Outpatient intensification of mesalamine-based therapy, rectal therapies when appropriate, and close follow-up are common themes in pathways—always aligned with local guidelines and specialist input.

Severe ulcerative colitis (Truelove–Witts)

Severe disease is typically defined as six or more bloody bowel movements per day and at least one feature of systemic toxicity. Commonly taught thresholds include:

Tachycardia with pulse ≥ 90 beats per minute (interpreted in clinical context: pain, anxiety, dehydration, fever, medications, and comorbid conditions can all raise heart rate).
Fever with temperature ≥ 37.8 °C (100 °F).
Anemia with hemoglobin < 10.5 g/dL—often conceptualized as anemia attributable to inflammatory bleeding and marrow demand in the setting of active colitis, though other causes of anemia must be considered.
Raised ESR with ESR > 30 mm in the first hour—a nonspecific marker influenced by age, sex, anemia, immunoglobulin levels, and non-IBD conditions.

The severe category is not synonymous with “needs surgery,” but it overlaps substantially with what many centers now treat as acute severe ulcerative colitis (ASUC) when hospitalization criteria are met. Patients with severe Truelove–Witts features frequently warrant inpatient care, intravenous therapies in contemporary pathways, surgical consultation when indicated, and structured reassessment schedules.

Moderate ulcerative colitis (Truelove–Witts)

Moderate disease is best understood as the residual category: patients who do not meet the mild definition and do not meet the severe definition. Examples include:

Intermediate stool frequency (often taught as roughly four to five bloody stools per day), especially without the full systemic pattern of severe disease.
High stool counts without systemic markers—for instance, frequent bloody movements but stable hemoglobin, no tachycardia by the threshold, no fever, and ESR not meeting the severe cutoff.
Systemic abnormalities with lower stool frequency—a patient may not reach six movements daily yet still appear systemically unwell; such cases are not “mild” in a practical sense even if they fail the classic severe stool-count gate.

This heterogeneity is why moderate UC is the least standardized stratum in bedside teaching: it signals “more than mild” and should prompt escalation planning, objective monitoring, and often specialty review even when admission is not immediately required.

How to apply the variables reliably

Stool frequency and blood

Truelove–Witts was written in an era when “bloody diarrhea” was a central phenotype of interest. In practice, quantify stools over a consistent window (classically per 24 hours) and document whether blood is predominant versus streaks. Stool frequency alone can mislead in:

Rectal hypersensitivity and tenesmus, where small-volume passages inflate counts.
Concurrent infection (for example C. difficile), where diarrhea may worsen independent of UC activity.
Opioid use or ileus, where counts may be artificially low despite severe inflammation.

Pulse and temperature

Vitals should be interpreted as trends, not single points. Orthostatic changes, beta-blockade, autonomic disease, pregnancy, and sepsis from any source can distort pulse. Temperature should be measured with a consistent method; antipyretics and steroids may mask fever while inflammation remains substantial.

Hemoglobin

Hemoglobin reflects integrated blood loss, hemodilution with resuscitation, chronic iron deficiency, and bone marrow response. Compare to the patient’s baseline when known. In acute presentations, a “not yet low” hemoglobin does not exclude severe mucosal disease if hemoconcentration is present early, which is why repeat laboratory assessment is standard in ASUC pathways.

ESR

ESR rises in many inflammatory states and is influenced by fibrinogen and red cell factors; it may be less responsive than CRP in some scenarios, and it is not specific to colonic inflammation. Many modern pathways emphasize CRP alongside clinical indices, but ESR remains part of the classical Truelove–Witts teaching schema.

Relationship to other UC severity tools

Clinicians frequently encounter multiple frameworks in the same admission:

Truelove–Witts emphasizes stool frequency with blood plus systemic toxicity markers.
Mayo scoring systems incorporate endoscopic and physician global assessment components not present in Truelove–Witts.
Indices used during steroid therapy for acute severe UC (for example day-3 prognostic rules involving stool count and CRP in some protocols) answer a different question: trajectory under inpatient treatment rather than first-attack stratification alone.

These tools are complementary. Discordance is common: a patient may have endoscopically severe mucosal disease with modest stool frequency due to constipation-dominant phenotypes, or frequent symptoms with less dramatic mucosal changes due to functional components—another reason the index should not be applied in isolation.

Special populations and common pitfalls

Pediatric patients may have different baseline vitals and hemoglobin ranges; adult thresholds do not transfer literally without pediatric-specific guidance.
Pregnancy alters heart rate, hemoglobin expectations, and drug choices; obstetric and gastroenterology co-management is essential.
Older adults may have blunted fever response, baseline anemia from chronic disease, or cardiovascular medications that mask tachycardia.
Immunosuppression and advanced therapies can modify both symptoms and objective markers; a “quiet” patient can still have dangerous inflammation.
Infection must be excluded or treated when presentation suggests severe colitis; superimposed infection changes management even when Truelove–Witts features are present.

Using this calculator on CalcMD

This calculator applies the widely taught Truelove–Witts rules to the entered stool frequency (predominantly bloody stools), pulse, temperature, hemoglobin, and ESR. It is intended for education and clinical decision support, not as a substitute for specialist evaluation, endoscopy when indicated, or institutional ASUC protocols. Always reconcile outputs with the full clinical picture, trajectory over hours to days, medication exposure, comorbidities, and local pathways.