THE DIAGNOSTIC-VALUE OF SERUM UREA CREATININE RATIO IN DISTINGUISHINGBETWEEN UPPER AND LOWER GASTROINTESTINAL-BLEEDING - A PROSPECTIVE-STUDY/

The predictive value of a urea/creatinine ratio greater than or equal to 100 for indicating upper gastrointestinal bleeding was evaluated in 78 consecutive patients with a history of gastrointestinal bleeding 2 4 hours of less before admission. Serum beta-2-microglobulin was measu red to elucidate whether renal hypoperfusion plays a part in elevation of the urea/creatinine ratio. The predictive value of a urea/creatini ne ratio greater than or equal to 100 in terms of upper gastrointestin al bleeding was 95% (95% confidence interval (CI): 83-99%), whereas th e predictive value of a urea/creatinine ratio < 100, indicating lower gastrointestinal bleeding, was 41% (CI: 25-59%). No statistically sign ificant differences were found between serum beta-2-microglobulin leve ls in upper and lower gastrointestinal bleeders. We conclude that a ur ea/creatinine ratio greater than or equal to 100 strongly indicates an upper gastrointestinal bleeding source and that the main cause of a h igh ratio is not renal hypoperfusion.