Spot urinary protein analysis for excluding significant proteinuria in pregnancy

Abstract

The aim of this research was to compare the accuracy of urinary protein/creatinine ratio (PCR) and albumin/creatinine ratio (ACR) in defining optimal cut-off points to rule-out significant proteinuria (>300 mg/24 h) in pregnancy. The secondary outcome measure was to determine the investigation of choice to evaluate proteinuria used by maternity units in the UK. PCR and ACR were calculated on first (PCR1, ACR1) void urine samples of the 24-hour urinary protein collection (24UP). Sensitivity and specificity was calculated for different cut-off points for PCR1 and ACR1 to rule-out significant proteinuria. An online survey was sent to RCOG members questioning them on their investigation of choice to evaluate proteinuria. We concluded from our results that both PCR and ACR are good rule-out tests for significant proteinuria in pregnancy using cut-off points of <20 mg/mmol and <2.5 mg/mmol. PCR is the investigation of choice in 56% of UK units studied.

Keywords::

• albumin:creatinine ratio
• diagnostic accuracy
• pre-eclampsia
• pregnancy
• protein:creatinine ratio
• 24UP

Acknowledgements

Midwives of Portiuncula Hospital who assisted in acquisition of data. Biochemistry Department at Portiuncula Hospital who were involved in analysis of urinary specimens. C.A.E. Walsh assisted in the drafting of the abstract.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Ethical approval was obtained from the Clinical Research Ethics Committee, Galway University Hospital, Galway on 30 March 2010. The corresponding reference number is C.A. 420.