Journal of North Khorasan

Background & objectives: The diagnosis of UTI is based on urine culture .culture results correlates perfectly to the mode of collecting samples. In this study, we tried to determine that how much delay in lab analysis can affect the test results. Material & Methods:This was a cross-sectional study of 240 urine samples, collected from infants and children with urinary bags (120 cases) and midstream method (120).the samples were placed in the refrigerator or at room temperature. Then the specimens were examined for urine culture at 0,2,4 hours post sample collection. Spss16 was used for data analysis and compiled descriptive results are expressed as percentage and the Cochran test was used for comparisons. Results:Results of urine cultures collected with urinary bags showed statistically significant difference between samples which were kept in room temperature for 2 hours (p<0.01) but this was not true for specimens kept in the refrigerator or collected using midstream method. In both bag and midstream samples the results of urine cultures were statistically significant after 4 hours remaining in environment temperature (p<0.01) Conclusion:Results of this study shows that urine cultures are more likely to be falsely positive with time passing from the sample collection but if the specimen is kept in the refrigerator the likelihood of false positive cultures will be decreased.