对53例上消化道出血和31例下消化道出血病例的观察结果表明,采用血清尿素氮(BUN)与肌酐(Cr)比值对鉴别上、下消化道出血有较高的准确性.85％的上消化道出血病人其比值≥20,而90％的下消化道出血病人其比值<20,总准确率达88％.该比值对急性消化道出血的鉴别诊断及选择进一步检查程序有一定的临床价值. The observation of 53 cases of upper gastrointestinal bleeding and 31 cases of lower gastrointestinal bleeding showed that the use of serum urea nitrogen (BUN) and creatinine (Cr) ratio for the identification of upper and lower gastrointestinal bleeding with high accuracy 85% Of patients with upper gastrointestinal bleeding ratio ≥ 20, and 90% of patients with lower gastrointestinal bleeding ratio <20, the total accuracy of 88% of the ratio of acute gastrointestinal bleeding in the differential diagnosis and selection of a further examination of the program has a certain Clinical Value.