Impact of Pre-analytic Practices on Diagnostic Accuracy of Urine Cultures- A Retrospective Study

Sukanya  Sudhaharan; Umabala  Pamidimukkala; Shivaprasad  J; Sabaa  Naaz

doi:10.18502/jmb.v13i3.19500

Sukanya Sudhaharan Department of Microbiology, Nizam’s Institute of Medical Sciences, Hyderabad,India
Umabala Pamidimukkala Department of Microbiology, Nizam’s Institute of Medical Sciences, Hyderabad, India.
Shivaprasad J Department of Microbiology, Nizam’s Institute of Medical Sciences, Hyderabad, India.
Sabaa Naaz Department of Microbiology, Nizam’s Institute of Medical Sciences, Hyderabad, India.

DOI: https://doi.org/10.18502/jmb.v13i3.19500

Keywords: Asymptomatic bacteriuria, Complete urine analysis, Contamination

Abstract

Background: Several pre-analytic factors adversely affect the diagnostic accuracy of urine cultures.The aim of our study is to identify and evaluate preanalytic practices associated with urine specimensand assess their impact on the accuracy of urine culture microbiology.

Methods: A retrospective study was conducted from January 2019 to June 2019 on urine culturesshowing discrepant results. This included 225 patients whose culture showed growth of a singlepathogen with no pus cells in the Gram stain. The details regarding the sample type, repeat culturessent, and complete urine analysis (CUE), were analyzed.

Results: Of the 225 samples, 208(93.4%) were clean catch and 17 (3.1%) were catheter catch. Of17 patients with catheter catch, urine culture and CUE were done in 12 (70.5%) patients. CUE wasnormal in 10 (83.3%) of the patients. The culture was sent within 1-7 days in 12 (70.5%) patients. Of208 patients with clean catch urine culture, CUE was done in 174 (83.6%) patients. CUE was normalin 162 (93.1%) of patients. The culture was sent in 1-7 days in 146 (70.1%) patients. Escherichia coliwas the predominant organism isolated in clean and catheter catch. Of 450 polymicrobial cultures,Gram stain showed pus cells with/without organisms in 66(14.6%) of cases.

Conclusion: In the majority of the urine cultures, there was no correlation between microscopy andculture. The samples would have been sent without proper indication and collected improperly. Apositive urine culture alone is insufficient for the diagnosis of UTI, it has to be correlated withmicroscopy and clinical history