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Urinary and Genital Disorders (Children)

Nitrites in the Urine



I`m really hoping someone can answer this question for me as I am very worried. My 4 year old daughter has suffered with UTI infections and has had 2 psudmounoues infections in the past eleven months. She is to have a mag3 scan and a another ultrasound in 4 weeks. However for the last 4 weeks my daughter`s urine as had nitrites in it. The doctor has sent it to the lab and no infection is present, which is very good. However my doctor cannot understand why the urine has nitrites in it and neither does the consultant. I am very scared something is wrong. If no infection is showing then why are nitrites present on the test strips? It has been 5 times now. My doctor wanted a another sample today after she had eaten as I always have the first urine sample of her in the morning and he wanted one when she had eaten. This was done but still nitrites present and again he is sending of to the lab. I have tried in vain to find information about what other things can cause nitirites and everytime it is always the same (infection) but no infection is being grown in the lab. Nothing else is coming up on the test strip dips. My daughter is on a prophalactic dose of trimerprim. This is very worring to me as the doctors and specialist do not know why these nitrites are in there, please someone have a answer for me? Why are nitrites present in the urine, but no infection present? Best wishes.


Unfortunately, there is not a good answer to your question. Bacteria produce an enzyme that convert nitrates (normal in urine) to nitrites. However, it is important to document that the culture is positive before concluding that a urinary tract infection is present. In fact, if the urine only shows positive nitrites and no other signs of UTI, only 40% have a positive culture. The other thing to consider is that UTIs usually cause symptoms such as burning, frequent urination, and suprapubic pain. It is reassuring that she is not experiencing these symptoms.

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Response by:

Jack S Elder, MD, FACS, FAAP Jack S Elder, MD, FACS, FAAP
Clinical Professor of Urology
School of Medicine
Case Western Reserve University