OBJECTIVE:To determine whether a urine collection of Ͻ24 hours duration accurately assesses the level of proteinuria in inpatients being evaluated for preeclampsia.
STUDY DESIGN:Patients admitted to the University of Mississippi between January and June of 1998 for evaluation of preeclampsia underwent two consecutive 12-hour urine collections. Each collection was analyzed for total protein, total calcium, total volume, and urine creatinine. A concurrent serum creatinine value was obtained. The protein:creatinine ratio, calcium: creatinine ratio, and creatinine clearance were calculated. Pearson's correlation, sensitivity, specificity, and positive and negative predictive values were assessed.
RESULTS:A total of 25 patients (86%) were preeclamptic. Total protein, the protein: creatinine ratio, and serum creatinine were significantly correlated between the first and second urine collection. The sensitivity and specificity of the 12-hour urine collection was 96% and 100%, respectively.
CONCLUSION:A 12-hour urine collection accurately depicts the amount of proteinuria in hospitalized gravidas being evaluated for preeclampsia.Hypertensive disease is the most commonly encountered significant medical complication of pregnancy, affecting an estimated 5% to 10% of all pregnancies.1 Preeclampsia, as mild or severe disease, is responsible for ϳ70% of the hypertensive disease observed during pregnancy. To insure the accuracy of the diagnosis of preeclampsia, the amount of proteinuria must be accurately evaluated.2 Traditionally, performing a 24-hour urine collection for total protein has been promoted and practiced as a "gold standard." [3][4][5] The rationale behind the 24-hour urine collection is that in preeclamptic patients, the fluctuation of protein loss in the urine varies significantly over a 24-hour period, and collections of less than this duration may not accurately reflect the actual amount of daily protein loss.Collection of a 24-hour urine specimen can be associated with several problems. First, this large volume of urine is heavy and renders the collection vessel cumbersome for patients and hospital personnel to manage. Second, after collection of the 24-hour urine specimen, laboratory analysis takes more time, further delaying diagnosis and directed management. Hence, several investigations have attempted by variable methodologies to shorten the time period and to better identify the patient with preeclampsia. These have included dipstick evaluation of single voided specimens for proteinuria and the use of protein:creatinine ratios in single voided specimens. Reports of the accuracy of these methods have been inconsistent. 6 -8 Neither assessment tool has been found to be sufficiently suitable to replace the 24-hour urine collection as the standard recommended methodology.The purpose of this investigation was to determine whether a shorter period of urine collection would still accurately reflect the level of proteinuria that otherwise would be measured in a 24-hour urine collection, therefore effectively d...