Michael Hinckley and Cayden Westwood, Dixie State University
Life Sciences
Clinical laboratory standards state that urine samples should be tested within 2 hours of collection. If testing is delayed beyond that time frame the sample needs to be refrigerated to inhibit urea conversion to ammonia and an increase in urine pH. Here medical lab science students investigated whether urine samples left at room temperature for 48 hours resulted in significant increases in urine pH with concomitant microbial growth. Five clean-catch urine specimens were obtained and promptly tested for pH levels using a sterile pH meter (EcoTestr, Oakton Instruments). Samples were then aliquoted into capped and uncapped containers that were left at room temperature. Samples were tested at 0, 8, 20, 24, 32 and 48 hours. The pH values from the uncapped and capped samples from these time periods were analyzed using a paired two tailed t-test. Results indicated one sample out of five was significant (P = .05). Initial samples were gram stained, then read to determine the presence of bacteria. Specimens were cultured on 5% Sheep Blood and MacConkey agar plates. Plates were read for bacterial growth at 24 hours incubation and growth was identified on two samples. At 48 hours, both uncapped and capped urine cultures were plated again and three samples demonstrated bacterial growth the following day. Microbial testing identified normal urogenital flora and pathogenic bacteria. Urine with pathogenic bacteria demonstrated significant increases in pH, while additional cultures with bacterial growth also increased but not with significance. Future studies could employ a larger sample size from both healthy and diseased individuals. Furthermore, identification of microbes that will thrive in acidic and alkaline pH would be of interest.