Patient: I (male) seem to be urinating a lot lately; there is no pain or burning. I was concerned so I took the at home UTI test – it tests for leukocytes and nitrite. I did 6 test strips (3 day period). The strange thing that I can’t understand is that the 3 morning strips showed no leukocytes and no nitrite. The afternoon/evening strips showed a high level of leukocytes and no nitrite. What would cause the difference in leukocytes?
Doctor: Hi.Thanks for your query, albeit unique.To recapitulate: Young male – only symptoms being urinating a lot – no pain – no burning – took ‘at home UTI test’ – 3 morning strips showed no leukocytes and no nitrite – afternoon/evening strips showed a high level of leukocytes and no nitrite – Wants to know why the difference…So Either there is false negative in the morning or false positive in the afternoon samples.The possible reasons are:Something in the food / beverages like vitamin C or so, that can show positive results in the afternoon/evening samples.Another reason can be high concentration in these samples causing to detect, but the morning sample diluted enough to show negative results.It is ultimately the urine test strip test for white blood cells detects ”leukocyte esterase”, which is present in azurophilic granules of monocytes and granulocytes (neutrophilic, eosinophilic and basophilic).This has to be in the enough concentration to be picked up by the strip.Well these are the possible reasons for the disparity.The most important point to know is these are ”screening tests” and not the final diagnostic test.Hence it is mandatory that you should get a confirmed diagnosis by sending your Urine sample for- regular Laboratory testing : for routine, microscopy and culture and sensitivity- preferably before the antibiotics are started.I hope this clears your doubts and please feel free if you have further relevant queries or if you feel that there is a gap-of-communication.