Acute Renal Failure without Oliguria

To the Editor: In reading the article of Anderson et al. (N Engl J Med 296:1134, 1977) on nonoliguric acute renal failure (ARF) I was surprised by the marked heterogeneity of their oliguric patients. In these oliguric patients the U/P creatinine was 16.5±3 (S.E.M.). For n = 24 patients a standard deviation of 14.1 may be calculated. It is apparent from this figure that the values of U/P creatinine must have been substantially skewed, with many greater than 30. The U/P creatinine ratio has been successfully used as a marker to differentiate prerenal azotemia from that of acute renal failure,.