Diagnostic performance of rapid screening tests for asymptomatic bacteriuria among pregnant women in a tertiary care hospital in India

Asymptomatic bacteriuria (ASB) during pregnancy is associated with adverse maternal and foetal outcomes, necessitating early and reliable detection. While urine culture remains the reference standard, its limited availability and delayed turnaround time highlight the need for effective rapid screening tests. This study aimed to evaluate the clinicodemographic profile, microbiological spectrum, and diagnostic performance of selected rapid screening tests for early detection of ASB among pregnant women attending a tertiary care centre in India. A cross-sectional study was conducted among 97 antenatal women. Clinicodemographic and comorbidity data were collected using a structured questionnaire and analysed for association with culture-confirmed asymptomatic bacteriuria. Midstream urine samples were subjected to wet mount microscopy, Gram staining, catalase testing, and semi-quantitative urine culture. Culture positivity was defined as ≥ 105 CFU/mL of a single uropathogen. Diagnostic indices, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were calculated for individual tests and their parallel combinations. The prevalence of ASB was 22.7%. Staphylococcus aureus was the predominant isolate. Wet mount microscopy and catalase testing demonstrated 100% sensitivity and NPV, whereas Gram staining showed high specificity (97.3%) and PPV (90.0%). Parallel combinations of screening tests did not improve diagnostic performance beyond individual high-performing tests. Simple, rapid screening tests, particularly wet mount microscopy and catalase testing, are effective for ruling out ASB in pregnancy, while Gram staining serves as a reliable confirmatory test. Rational selection of screening tools can enhance antenatal ASB detection, especially in resource-limited settings.