title: Usage of spot urine protein to creatinine ratios in the evaluation of preeclampsia.
abstract: OBJECTIVE
  The objective of the study was to prospectively compare spot urine protein to creatinine (P:C) ratios with 24 hour urine collections for protein in women being evaluated for preeclampsia.
  
  
  METHODS
  A spot urine P:C ratio was obtained at the beginning of 24 hour urine collections from 126 patients admitted to evaluate for preeclampsia. Correlation between the spot P:C ratio with the 24 hour urine collections was calculated. Receiver operator characteristic curves were constructed to determine best P:C cut-offs for 300 mg and 5000 mg protein per 24 hours.
  
  
  RESULTS
  Random spot P:C ratios were strongly correlated with 24 hour urine protein levels (Pearson r = 0.88). The optimal P:C cut-offs were 0.21 (300 mg per 24 hours) and 3.0 (5000 mg per 24 hours). A P:C ratio of less than 0.21 (300 mg per 24 hours) had a negative predictive value (NPV) of 83.3% and a P:C ratio of less than 3.0 (5000 mg per 24 hours) had 100% NPV.
  
  
  CONCLUSIONS
  Urine spot P:C ratio correlated well with 24 hour urine collections for protein but was not justified as a substitute for timed collections.
authors.affiliation: Department of Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham, AL 35249-7333, USA. tlwheeler@uabmc.edu
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Wheeler
authors.forename: Dawn W
authors.initials: DW
authors.lastname: Blackhurst
authors.forename: Eric H
authors.initials: EH
authors.lastname: Dellinger
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Ramsey
mesh_terms: D000328:Adult; D003404:Creatinine / Q000652:urine; D005260:Female; D006801:Humans; D011225:Pre-Eclampsia / Q000175:diagnosis* / Q000652:urine; D011247:Pregnancy; D011446:Prospective Studies; D011507:Proteinuria / Q000175:diagnosis* / Q000209:etiology; D016482:Urinalysis / Q000379:methods*
chemical_list: D003404:Creatinine