[Question #5348] Mid Stream Urine

24 months ago
Appreciate this question will be answered by Dr Edward Hook or Dr H Hunter Handsfield.

I have recently completed my STD tests for HIV, Gonorrhea, Chlamydia, Syphilis etc under my checkup and the results are negative.  However I have handed over middle stream urine instead of first part of urine for my urine specimens.  Will this affect the accuracy of the negative results.  If it does not affect the accuracy of the results why first part of urine is preferred for the urine tests.  I hope you can help me to clear this confusion.  Thank You.
Edward W. Hook M.D.
Edward W. Hook M.D.
24 months ago
Welcome to the Forum.  I'll be glad to provide some information.  The principle of using urine to test for gonorrhea and chlamydia is based on the very high sensitivity of the test used and the fact that urination "washes" secretions out of the urethra.  If a person has gonorrhea or chlamydia, these secretions will give a positive test.  The FDA approval for these tests specifies use of the initial portion of a urine specimen because of the assumption that the concentration of bacteria, if present will be highest in the initial portion of the specimen.  Since the tests have become available however, real life studies show that reduction in sensitivity when a mid-stream rather than initial urine specimen is, on average, small, 1 or 2% and therefore does not meaningfully reduce the average accuracy of the test. You do not mention the circumstances of your testing but if the specimen was collected as part of a routine sexual health check-up, the results are very, very likely to be accurate.  OTOH, if you tested following an exposure or to evaluate symptoms and want to be completely confident of the results, you may wish to test again.  If you re-test, it is far more likely than not that your test results will be the same for both specimen types.

I hope that this comment is helpful.  EWH
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H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
23 months ago
Since you asked a new question on a simlar topic (and probably about the same STD evaluation), this thread is being closed.
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