title: Should the spot albumin-to-creatinine ratio replace the spot protein-to-creatinine ratio as the primary screening tool for proteinuria in pregnancy?
abstract: OBJECTIVE
  To determine the correlation between the spot albumin-to-creatinine (ACR) ratio and protein-to-creatinine ratio (PCR) in pregnancy and if either test is predictive of adverse pregnancy outcome.
  
  
  METHODS
  Prospective consecutive cohort study in a single tertiary centre examining 181 patients undergoing proteinuria screening after 20weeks of pregnancy. A spot PCR and ACR was performed on the first void of the day. Comparison was with linear and logistic regression and ROC curve. Optimal values for the ACR were obtained and compared to a PCR value of 30mg/mmol with respect to adverse pregnancy outcomes.
  
  
  METHODS
  Birth weight <10th centile, preterm birth <32 and <37weeks, placental abruption, caesarean section, induction of labour, fetal death in utero or neonatal death, Apgar score <5 at 1min and/or 5min, pulmonary oedema, sustained blood pressure >170/110mmHg, magnesium infusion or labetalol infusion during labour.
  
  
  RESULTS
  254 tests were performed. The ACR and PCR were highly correlated (r=0.95, p<0.001) and the area under ROC curve was 0.98. An ACR of 13.4mg/mmol corresponded to a PCR of 30mg/mmol. Neither was more predictive of adverse pregnancy outcome nor was the level of proteinuria.
  
  
  CONCLUSIONS
  The ACR is not inferior to nor does it perform better than the PCR in screening for proteinuria in pregnancy. Clinicians should use the test with which they are more familiar and may wish to assess local laboratory costs and methods in their selection.
authors.affiliation: Department of Maternity Services, Royal Women's Hospital, Cnr Flemington Rd and Grattan St, Parkville 3053, Australia. Electronic address: tom.cade@thewomens.org.au.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Cade
authors.affiliation: Department of Maternity Services, Royal Women's Hospital, Cnr Flemington Rd and Grattan St, Parkville 3053, Australia.
authors.forename: Paul Champion
authors.initials: PC
authors.lastname: de Crespigny
authors.affiliation: Department of Maternity Services, Royal Women's Hospital, Cnr Flemington Rd and Grattan St, Parkville 3053, Australia.
authors.forename: Tien
authors.initials: T
authors.lastname: Nguyen
authors.affiliation: Department of Statistical Risk Management, KPMG, 147 Collins St, Melbourne 3000, Australia.
authors.forename: John R
authors.initials: JR
authors.lastname: Cade
authors.affiliation: Department of Maternity Services, Royal Women's Hospital, Cnr Flemington Rd and Grattan St, Parkville 3053, Australia; Department of Obstetrics and Gynecology, University of Melbourne, Australia.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Umstad
mesh_terms: D000419:Albuminuria / Q000652:urine; D015415:Biomarkers / Q000652:urine; D015992:Body Mass Index; D001835:Body Weight; D003404:Creatinine / Q000652:urine*; D005260:Female; D006785:Hospitals, University; D006801:Humans; D011225:Pre-Eclampsia / Q000175:diagnosis* / Q000652:urine; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D011507:Proteinuria / Q000652:urine*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016482:Urinalysis / Q000379:methods
chemical_list: D015415:Biomarkers; D003404:Creatinine
keywords: EPH complex; Preeclampsia; Proteinuria; Toxaemia of pregnancy