Urinalysis: Obstetrics and William A. Alto

A urinalysis is where a sample of a person’s urine is taken and a dipstick in dipped into the urine to test for many different elements; these can include leukocytes, blood, protein, sugar, ketones, ph, nitrites, bilirubin and ascorbic acid. These elements can help in diagnoses for bladder or kidney infections, diabetes, dehydration and preeclampsia. In antenatal care a urinalysis is performed at the very first visit with a dipstick and the sample is then referred to a pathology laboratory to be examined under the microscope and incubated for micro, culture and sensitivity testing (3 centres collaboration 2010). Some antenatal care providers will continue to perform dipstick urinalysis at each and every appointment, whereas other providers will only perform one at every appointment if the patient presents with Gestational diabetes with oral glucose screening, Pre-eclampsia with blood pressure and Asymptomatic bacteriuria [urine infection with no symptoms] with a culture at the first visit (IHS.gov 2005).
According to an article in the Journal of Family practice by William A. Alto, Screening for gestational diabetes using urine dipsticks for glycosuria is ineffective with low sensitivities. False-positive tests outnumber true positives 11:1. A 50-g oral glucose challenge is a better test. Tests for glycosuria after this blood test are not useful. Proteinuria determined by dipstick in pregnancy is common and a poor predictor for preeclampsia with a positive predictive value between 2% and 11%. If the blood pressure is elevated, a more sensitive test should be used. After urinalysis at the first prenatal visit, routine urine dipstick screening should be stopped in low-risk women. Urinalysis can be a quick and reliable indicator for some conditions such as UTI, dehydration and malnourishment (ketonuria). However in the case of gestational diabetes and pre eclampsia, urinalysis is a poor indicator, and any positive outcomes need to be followed up by further

References: www.ihs.gov/medicalprograms/mch/m/.../urinprenat9405.doc Noreen Murray, Caroline S E Homer, Gregory K Davis, Julie Curtis, George Mangos and Mark A Brown 2002, MJA, ‘The clinical utility of routine urinalysis in pregnancy: a prospective study’ MJA 2002; vol177: pp.477-480 Urinalysis By Dipstick For Proteinuria - 3centres Collaboration. 2012. Urinalysis By Dipstick For Proteinuria - 3centres Collaboration. [ONLINE] Available at: http://3centres.com.au/guidelines/urinalysis-by-dipstick-for-proteinuria/. [Accessed 30 August 2012]. William A. Alto 2005, The Journal of Family Practice, ‘No need for routine glycosuria/proteinuria screen in pregnant women’, November 2005 • Vol. 54, No. 11