Diagnostic sensitivity of microscopic and chemical analysis of the urine in diagnosis of urinary tract infections
Leukocyte in the microscopic examination of the urine, and leukocyte esterase (LE) and nitrite positivity in chemical urine analysis all indicates urinary tract infection (UTI). We aimed to demonstrate the diagnostic sensitivity of urine strips as well as the microscopic analysis of urine and to determine the effect of isolated pathogens in the urine culture as well as the number of colonies of pathogens and pathogen species on these parameters. We retrospectively analyzed the results of patients with a prediagnosis of UTI between August 2014 and January 2015. According to the amount and variety of pathogens isolated in urine cultures, patients were divided into two groups of patients. Group1 consisted of patients with more than 105 cfu/ml and group 2 consisted of patients with 103-105 cfu/ml in urine culture. Group 3 was consisted of patients with Escherichia Coli (E. Coli) in urine culture and group 4 was consisted of patients with pathogens other than E. Coli in urine culture. Diagnostic sensitivity of LE, nitrite and leukocyturia were 46%, 18% and 57%, respectively. Diagnostic sensitivity was 48% when at least one positive result of LE and nitrite. Sensitivity reached 59% when at least one positive result of LE, nitrite and leukocyturia. LE, nitrite and leukocyturia test results were significantly different in group 1 compared to those in group 2(all p<0.001). LE and nitrite results were significantly different in group 3 compared to group 4(p=0.004 and p=0.036 respectively). According to the results of this study; highest diagnostic sensitivity has been reached at least one positive result of LE, nitrite test or with leucocyturia found however, even in this condition, all patients have not been diagnosed with these tests. The breeding pathogen species and number of the colonies isolated in urine culture have been found to be effective factor on diagnostic sensitivity.
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