clinical based scales to assess severity of ulcerative colitis (UC)

Last reviewed 01/2018

Severity of ulcerative colitis

The severity of ulcerative colitis can be classified as mild, moderate and severe

In adults these categories are based on the Truelove and Witts' severity index

  Mild Moderate Severe
Bowel movements (no. per day) Fewer than 4 4-6 6 or more plus at least one of the features of systemic upset (marked with * below)
Blood in stools No more than small amounts of blood Between mild and severe Visible blood
Pyrexia (temperature greater than 37.8°C) * no no yes
Pulse rate greater than 90 bpm * no no yes
Anaemia (< 10g/100mL)* no no yes
Erythrocyte sedimentation rate (mm/hour) * 30 or below 30 or below above 30


In children and young people these categories are based on the Paediatric Ulcerative Colitis Activity Index (PUCAI)

Paediatric Ulcerative Colitis Activity Index (PUCAI)

Disease severity is defined by the following scores:

  • severe: 65 or above
  • moderate: 35-64
  • mild: 10-34
  • remission (disease not active): below 10
Item Category/Points
Abdominal pain

No pain = 0

Pain can be ignored = 5

Pain cannot be ignored = 10

Rectal bleeding

None = 0

Small amount only, in less than 50% of stools = 10

Small amount with most stools =20

Large amount (50% of the stool content) = 30

Stool consistency of most stools

Formed = 0

Partially formed = 5

Completely unformed = 10

Number of stools per 24 hours

0-2 = 0 points

3-5 = 5 points

6-8 = 10 points

>8 = 15 points

Nocturnal stools (any episode causing wakening)

no = 0 points

yes = 10 points

Activity Level

No limitation of activity = 0

Occasional limitation of activity = 5

Severe restricted activity = 10

Sum of PUCAI (0-85)

Be aware that there may be an increased likelihood of needing surgery for people with any of the following:

  • stool frequency more than 8 per day
  • pyrexia
  • tachycardia
  • an abdominal X-ray showing colonic dilatation
  • low albumin, low haemoglobin, high platelet count or C-reactive protein (CRP) above 45 mg/litre (bear in mind that normal values may be different in pregnant women)