Quantitation of proteinuria in pregnancy by the use of single voided urine samples.

The most commonly used method to measure urinary protein involves a 24-hour urine collection. In a study of 54 specimens, we found excellent correlation between the protein content of a 24-hour urine collection and the protein/creatinine ratio of a single urine sample (r = 0.9936; P less than .0001). We conclude that the protein/creatinine ratio of a single urine specimen represents a highly accurate method to assess renal function in the pregnant patient, and seems clearly more practical than the 24-hour urine collection.