Screening for asymptomatic bacteriuria in pregnant women: urinalysis versus urine culture.

A diagnostic test study was conducted to evaluate the diagnostic performance of a simple urinalysis as a screening test for asymptomatic bacteriuria (ABU) in pregnant women. Seven hundred and seventy four asymptomatic pregnant women attending their first antenatal care at Srinagarind Hospital from June 1, 1994 to January 31, 1995 were studied. Simple urinalysis and urine culture were performed on all 774 subjects. The presence of > or = 5 WBC/HPF of centrifuged urine indicated a positive test. ABU was defined as the presence of > or = 10(5) colony forming units of single bacteria per milliliter of urine. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of simple urinalysis in detecting ABU, using urine culture as a gold standard were calculated. Simple urinalysis had a 18.4 per cent sensitivity, 97.2 per cent specificity, 45.7 per cent positive predictive value, 90.4 per cent negative predictive value and 88.4 per cent accuracy in detecting ABU. Because of its low sensitivity and the possible consequences of ABU, simple urinalysis should not be used as a screening test for ABU.