Objective: To determine the prevalence of asymptomatic bacteriuria (ABU) in pregnant women and diagnostic performance of reagent strip test for screening of ABU using single and double urine culture criteria.

Material and Method: Pregnant women attending their first antenatal care at Rajavithi Hospital Bangkok, between August 22 and November 4, 2011 were enrolled to collect clean-catch midstream urine for reagent strip test and culture on blood and MacConkey agar plates. The second urine culture was collected only from participants who had the first positive urine culture.

Results: Sixty-one of the 754 cases (8.1%) got the positive first urine culture. Twenty of the sixty-one cases were still positive urine culture in the second culture. Therefore, prevalence of ABU was 8.1% and 2.7% using single and double urine culture as gold standard. Escherichia was the most common pathogen in both single and double urine culture (27.9% and 40%, respectively). The urine dipstick nitrite, leukocyte, and both test by using double urine culture had a sensitivity of 35.0%, 50.0%, and 20.0%, specificity of 86.5%, 52.2%, and 93.2%, positive predictive value (PPV) of 6.6%, 2.8%, and 7.4%, and negative predictive value of 98.0%, 97.5%, and 97.7%, respectively. All diagnostic performances of double-urine culture were comparable with single-urine culture except marked worse PPV.

Conclusion: Prevalence of ABU in pregnant women was decreased from 8.1 to 2.7% using single and double culture as gold standard. Reagent strip testing is not sensitive for screening of ABU; either single or double urine culture were used as gold standard.

Keywords: Asymptomatic bacteriuria, Pregnancy, Reagent strip, Single urine culture, Double urine culture