Predictive role of proteinuria in urinary tract infection

Introduction: Urine culture is considered as Holy Grail in diagnosis of Urinary Tract Infection (UTI). However, the significance of preliminary urinalysis cannot be neglected. Aim: To evaluate proteinuria as a predictor of UTI. Materials and Methods: This study was conducted at the Department of Microbiology, Dr. Baba Saheb Ambedkar Hospital, New Delhi, India, over a period of three months (April 2015 to June 2015). Urine specimens from clinically suspected cases of UTI were analysed microscopically for pyuria and by reagent strip test for albuminuria. The results were correlated with urine culture findings. Antimicrobial resistance for various antimicrobials was compared among proteinuria positive and negative cases. Statistical analysis was done by Fisher’s-exact test and p-value was calculated. A p-value ≤0.05 was considered significant. Results: A total of 369 urine samples received for both routine microscopy and culture, out of which 73 were proteinuria positive. And, out of these 73 samples, 32 were culture positive while 41 were culture negative. Among culture positive, 65.6% patients were symptomatic (21/32) while 34.4% were asymptomatic (11/32). Their age ranged from 5 months to 83 years. Male to female ratio was 1:1.5. Association between culture positivity and proteinuria was statistically significant (p<0.001) with 43.8% positive predictive value. Pyuria was observed in 42.5% cases. Out of 296 proteinuria negative samples, 36 were culture positive. β-lactam antibiotic resistance among proteinuria positive cases while chloramphenicol resistance among proteinuria negative cases was significantly high. Conclusion: Proteinuria as a urinalysis parameter may have good predictive power combined with the clinical presentation to diagnose UTI.