[Diagnosis of the bleeding site in gastrointestinal hemorrhage by the determination of the serum urea and creatinine ratios].

Serum urea/creatinine (Ur/Cr) ratios were determined in patients showing massive gastrointestinal (GI) bleeding in order to evaluate the bleeding site. In 36 cases of upper GI bleeding, serum Ur/Cr ratios were 119.1 +/- 4.0. The ratios were 54.1 +/- 12.1 and 58.4 +/- 10.3 in 23 cases of lower GI bleeding and 50 control cases without GI bleeding, respectively. The ratio in the upper GI bleeding cases were significantly higher than those in the lower GI bleeding and the control cases. In all cases of upper GI bleeding, except for 6 cases in which blood volume flowed into the GI tract was small, the ratios were beyond 81. On the other hand, in the lower GI bleeding and the control cases, the ratios were all below 81. Values over 81 in serum Ur/Cr ratios in upper GI bleeding cases continued until the 3rd day after bleeding. These results indicate that determination of serum Ur/Cr ratios is a simple and useful procedure for diagnosis of the bleeding site in cases showing massive GI bleeding.