Miller T R, Anderson R J, Linas S L, Henrich W L, Berns A S, Gabow P A, Schrier R W
Ann Intern Med. 1978 Jul;89(1):47-50. doi: 10.7326/0003-4819-89-1-47.
A prospective analysis of the value of urinary diagnostic indices in ascertaining the cause of acute renal failure was undertaken. Our results show that in the setting of acute oliguria a diagnosis of potentially reversible prerenal azotemia is likely with urine osmolality greater than 500 mosm/kg H2O, urine sodium concentration less than 20 meq/litre, urine/plasma urea nitrogen ratio greater than 8, and urine/plasma creatinine ratio greater than 40. Conversely, a urine osmolality less than 350 mosm/kg, urine sodium concentration greater than 40 meq/liter, urine/plasma urea nitrogen ratio less than 3, and urine/plasma creatinine ratio less than 20 suggest acute tubular necrosis. A significant number of oliguric patients will not have urinary indices that fall within these guidelines. In this setting, urine sodium concentration divided by the urine-to-plasma creatinine ratio (the renal failure index) and the fractional excretion of filtered sodium provide a reliable means of differentiating reversible prerenal azotemia from acute tubular necrosis.
对尿诊断指标在确定急性肾衰竭病因中的价值进行了前瞻性分析。我们的结果表明，在急性少尿的情况下，如果尿渗透压大于500 mosm/kg H2O、尿钠浓度小于20 meq/升、尿/血浆尿素氮比值大于8以及尿/血浆肌酐比值大于40，则可能诊断为潜在可逆的肾前性氮质血症。相反，尿渗透压小于350 mosm/kg、尿钠浓度大于40 meq/升、尿/血浆尿素氮比值小于3以及尿/血浆肌酐比值小于20提示急性肾小管坏死。相当数量的少尿患者的尿指标不在这些指导范围内。在这种情况下，尿钠浓度除以尿-血浆肌酐比值（肾衰竭指数）和滤过钠分数排泄提供了一种区分可逆性肾前性氮质血症和急性肾小管坏死的可靠方法。
