Upper GI bleed: an elevated urea: creatinine ratio helped diagnosis.

Clinical bottom line (level 1b)

  1. A urea:creatinine ratio of 100 or more helped diagnose an upper gastrointestinal bleed.
  2. The greater the ratio, the greater the blood lost.
Mortensen et al: Danish Medical Bulletin 1994; 41: 237-240
Expires July 2003

The study

Setting: acute hospital, Denmark

78 patients (aged range 22 to 96 years; mean 69, 69% male) admitted with GI bleeding up to 24 hours before admission

Excluded if
  • previous history of GI bleed

Independent blinded reference standard, applied in all patients from a consecutive appropriate spectrum.
Reference standard:

  • upper and/or lower endoscopy or Barium studies
Diagnostic test: urea:creatinine ratio (mmol/l: µ mol/l)

The evidence

pre-test probability of upper GI bleed: 74%, (95% CI: 65% to 84%)

diagnostic test upper GI bleed no bleed LR+
(95% CI)		 post-test probability LR-
(95% CI)		 post-test probability
urea:creatinine ratio 100 or more 38 3 4.4
(1.5 to 13) 		93% 0.41
(0.27 to 0.61) 		54%
total 58 20

Comments

  1. Four patients with no source defined after investigation.
  2. For patients with an upper GI bleed, the volume of blood lost correlates with the height of the value (rho=0.40, p<0.001). A strong positive=big bleed.

Citation

  1. Mortensen PB, et al: The diagnostic value of serum urea/creatinine ratio in distinguishing between upper and lower gastrointestinal bleeding. A prospective study. Danish Medical Bulletin 1994; 41: 237-240
Contributor: Alan Townsend, Sharon Straus and Chris Ball, July 2000
Reviewer:

Clinical Question.

    Patient suspected GI bleed
    Intervention or Exposure urea:creatinine ratio
    Outcome diagnosis of bleed