[The value of the urea/creatinine ratio for differentiation of up and lower gastrointestinal hemorrhage].

The urea/creatinine-ratio has been proposed as an instrument for differentiating upper from lower gastrointestinal haemorrhages. The predictability of this method was investigated in 105 cases with the source of bleeding to be in the upper gastrointestinal tract and in 31 cases in the lower gastrointestinal tract. Determination of the urea/creatinine-ratio predicted the site of bleeding in only 60% of the patients. The use of the ratio in diagnostic decision making would increase the number of unnecessary colonoscopies. Thus, the urea/creatinine-ratio does not appear to be clinically useful in predicting the localization of a gastrointestinal bleeding with adequate certainty.