Urinary albumin excretion in normal and diabetic subjects.

Using an albumin radio-immuno-assay, urinary albumin concentration and excretion rate have been measured in diabetics and control subjects overnight, after several hours ordinary activity and during two successive one hour periods of recumbency. The urine albumin concentration was relatively constant throughout each of the four collection periods. Variations in albumin excretion rate were directly related to changes in urine flow. In assessing changes in urinary albumin, concentration and urine flow should be reported as well as the calculated albumin excretion rate. In the diabetics, selected for absence of clinical proteinuria, the mean concentration of albumin did not differ significantly from that of the controls. The overnight albumin excretion rate was higher in the diabetics, but this was due to the greater volume of urine.