Inflammatory bowel disease: a raised platelet count made it more likely

Clinical bottom line (level 4)

  1. The following tests made inflammatory bowel disease more likely
    • elevated platelet count (LR + )
    • diarrhoea for > 14 days (LR + )
    • low serum albumin (LR + 4.2)
  2. No test could safely rule out inflammatory bowel disease.
Harries et al: Journal of Infection 1991; 22 : 247-250
Expires June 2004

The study

Setting: infectious disease unit, acute hospital, UK

239 patients (aged mean 42, 53% male) referred with a diagnosis of gastroenteritis

Excluded if
  • self-limiting proctitis


Independent unblinded reference standard, applied in all patients from a non-consecutive appropriate spectrum.
Reference standard:
  • Faecal pathogen detected by culture, or inflammatory bowel disease detected by characteristic histological and/or radiographic abnormalities
Diagnostic test: clinical features, blood count, serum albumin

The evidence

pre-test probability of inflammatory bowel disease: 11%, (95% CI: 7.3% to 15%)

diagnostic test inflammatory bowel disease no inflammatory bowel disease LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
platelet count > 450 x 109/l 16 3 42
(13 to 130) 		84% 0.41
(0.26 to 0.65) 		5%
diarrhoea for > 14 days 11 10 8.6
(4.1 to 18) 		52% 0.62
(0.45 to 0.85) 		7%
serum albumin < 35 g/dl 16 30 4.2
(2.7 to 6.6) 		35% 0.47
(0.30 to 0.75) 		6%
white cell count > 10 x 109/l 15 53 2.2
(1.5 to 3.3) 		22% 0.59
(0.39 to 0.91) 		7%
anaemia (Hb < 12 g/dl in women, < 14 g/dl in men) 16 47 2.7
(1.8 to 4.0) 		25% 0.52
(0.33 to 0.83) 		6%
ESR > 30 mm/h 17 72 1.9
(1.3 to 2.6) 		19% 0.56
(0.34 to 0.93) 		7%
blood in faeces 12 45 2.1
(1.3 to 3.4) 		21% 0.71
(0.50 to 0.995) 		8%
total 212 27

Comments

  1. Patients were selected using a retrospective chart review and only included if had a definitive diagnosis made. Consequently pre and post-test probabilites should be treated with caution.

Citation

  1. Harries AD, Beeching NJ, Rogerson SJ, et al: the platelet count as a simple measure to distinguish inflammatory bowel disease from infective diarrhoea. Journal of Infection 1991; 22 : 247-250
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Contributor: Chris Ball, June 2002
Reviewer:

Clinical Question.
Patient suspected gastroenteritis
Intervention or Exposure clinical features, blood tests
Outcome inflammatory bowel disease