Objective: Urine culture test (UCT), which is the gold-standard for urinary tract infections (UTI), requires higher cost, labour and time than complete urinalysis (CU). Therefore, it is important to assess prediction performance of CU's for UCT. The aim of our study is to demonstrate performance of strip leukocyte, erythrocyte, nitrite, microscopic leukocyte and microscopic erythrocyte tests in relation with UCT.

Material and Methods: Patients which had CU, UCT requests and UTI pre-diagnosis in Kemalpasa State Hospital Central Laboratory during 6 months period were included. Performance of strip leukocyte, erythrocyte, nitrite, microscopic leukocyte and erythrocyte tests was evaluated with reference to UCT. Sensitivity, specificity, PV+, PV-, LR+ and LR- values were calculated. Relationship between assessed tests and UCT was analysed by logistic-regression.

Results: Of 606 samples with CU and UCT request on the same day, UCT positivity was not detected in 513 (84,6%). Sensitivity was highest for strip leukocyte (trace) (93,5%), and lowest for strip erythrocyte (3+) (25,8%), and specificity was highest for nitrite (98,2%) and lowest for strip leukocyte (trace) (51,2%). Highest PV+ was in nitrite (86,4%) and highest PV- was in microscopic leukocyte (97,4%) and strip leukocyte (trace) (97,8%) tests. LR+ was calculated as 34,9 for nitrite and <10 for others. Smallest LR- values for microscopic leukocyte and strip leukocyte (trace) tests were found to be 0,15 and 0,13 respectively. In nitrite positivity, risk of significant growth in UCT increased by 45 times.

Conclusion: We conclude that combined evaluation of nitrite and strip leukocyte tests in CU before UCT request may contribute to the reduction of UCTs that can be performed unnecessarily in patients with UTI pre-diagnosis.