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I took Cipro and was tested for STI about week later. Can taking antibiotics affect the outcome of the test

Hi, and thanks for writing in with your question


We recommend waiting for 4 weeks after taking antibiotics before doing any testing for sexually transmitted infections (STIs). The reason for this is that sometimes we treat non-STI infections with the same antibiotics that can treat STIs.


Once antibiotics kill an infection it can take the body 3-4 weeks to actually get rid of the dead bacteria. Some STI tests (specifically the ones for chlamydia and gonorrhea) are so sensitive that they will detect the residual protein from the dead bacteria and report it as positive. This is essentially a “false positive” result, but it often leads to an additional, unnecessary dose of antibiotics if a testing provider doesn’t realize the infection could already have been treated with the previous antibiotics.


I hope this makes sense! If your STI testing was all negative 1 week after the ciprofloxacin, then you don’t need to worry. If something comes back positive on your tests, then I would recommend speaking with your care provider about the possibility of an already-treated infection.


Let us know if this does not answer your question or if you have any more questions or concerns.
Health Nurse

This answer was posted on September 11, 2019
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