Comparison of Urine Dipstick and Urine Culture in Diagnosis of Urinary Tract Infection

Abstract

This study was designed to evaluate the diagnostic accuracy of the rapid urine strip test, nitrite and leukocyte  esterase to predict urinary tract infection (UTI) by comparison with the gold standard of urine culture. A total of 492 samples were collected  from the patients receiving treatment at the Hospital for Tropical Diseases, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand, during the study period of January 2019 to August 2020. It was found that 58.13% were positive with bacterial culture. The prevalence of urinary tract infections in females (65.73%) was higher than that in males (34.27%). Almost all of the detected microorganisms were gram-negative, the Escherichia  coli (52.21%) was the most frequently isolated, followed by Klebsiella  pneumoniae   (9.18%) and Enterococcus faecalis (7.59%), respectively. The sensitivity of nitrite alone and leukocyte esterase alone were 33.64% and 81.12% with the specificity of 97.57% and 71.84%. The combination of nitrite and leukocyte esterase test on the sensitivity, specificity, positive predictive value and negative predictive value were 67.18%,  97.99%,  96.70%  and 77.25%,  respectively. This study indicated that the rapid urine strip test, nitrite and leukocyte esterase, can be used as a screening tool before urine culture for UTI diagnosis. The test also showed a high sensitivity, accurate predictive value, low cost, and easy interpretation suitable for screening of infectious and non-infectious urine.