title: Two-hour urine collection for evaluating renal function correlates with 24-hour urine collection in pregnant patients.
abstract: OBJECTIVE
  We sought to determine if 2-h urine collection for the assessment of urine protein excretion and creatinine clearance correlates with 24-h urine collection in pregnant patients with renal disease.
  
  
  METHODS
  We enrolled patients of gestational ages ranging from 8-41 weeks, admitted as inpatients and having undergone evaluation for renal function (n = 59). We obtained the following samples: 1) 2-h urine, and 2) 24-h urine. We measured serum creatinine concentration, urinary protein, creatinine concentration, and creatinine clearance. The data was analyzed using descriptive analysis, two-way ANOVA, univariate linear regression analysis, and Bland-Altman plot comparing the efficacy of 2-h urine results with 24-h urine results.
  
  
  RESULTS
  We analyzed the data on 51 patients. Total proteinuria calculated by protein/creatinine (P:C) ratio in the 2-h group correlated with the total protein measured in the 24-h group (1,840.8 +/- 786 and 1,944 +/- 1,060 mg [mean +/- SE], respectively, r2 = 0.95, P < 0.0001). Creatinine clearance correlated in the 2- and 24-h groups (111 +/- 42 and 122.5 +/- 50 ml/min, respectively; r2 = 0.73, P < 0.001).
  
  
  CONCLUSIONS
  Two-hour urine sampling offers the same clinical information as 24-h urine collection for the evaluation of renal function. Use of 2-h urine collection reduces the time of evaluation and diagnosis, whereby increasing patient compliance and reducing errors in performance of the tests.
authors.affiliation: University of Wisconsin Medical School, Department of Obstetrics and Gynecology, Sinai Samaritan Medical Center, Milwaukee, Wisconsin 53201-0342, USA.
authors.forename: W
authors.initials: W
authors.lastname: Evans
authors.forename: J P
authors.initials: JP
authors.lastname: Lensmeyer
authors.forename: R S
authors.initials: RS
authors.lastname: Kirby
authors.forename: M E
authors.initials: ME
authors.lastname: Malnory
authors.forename: F F
authors.initials: FF
authors.lastname: Broekhuizen
mesh_terms: D000328:Adult; D003404:Creatinine / Q000097:blood / Q000652:urine; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000652:urine*; D007677:Kidney Function Tests / Q000592:standards*; D008137:Longitudinal Studies; D011237:Predictive Value of Tests; D011247:Pregnancy; D011248:Pregnancy Complications / Q000652:urine*; D011446:Prospective Studies; D011507:Proteinuria / Q000652:urine; D013997:Time Factors; D016482:Urinalysis / Q000379:methods / Q000592:standards*
chemical_list: D003404:Creatinine