[Question #6183] Clamidya/Gonorrhea urine test

17 months ago
Hi, had a quick question on Clamidya/Gonorrhea urine test. I was treated as a precaution for syphilis with the shot three weeks ago. I ended up being negative. If I did a Clamidya/Gonorrhea urine test today which is three weeks after the shot, would those results be accurate or would the penicillin interfere with reliability. Hopefully this is the last time I talk to you guys
17 months ago
FYI it has been 49 days since the encounter
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
17 months ago
Welcome back, but sorry you found it necessary.

It is a common misunderstanding that antibiotics may suppress test results without curing an infection. That rarely happens. Your negative tests for gonorrhea and chlamydia are reliable, either because you were not infected or (theoretically) because the penicilllin cured gonorrhea. The kind of penicillin used for syphilis gives very low levels in the system, not enough to have any effect on gonorrhea or chlamydia. 

So no worries at all. Move on with no further worry about syphilis, viral hepatitis, gonorrhea, chlamydia, and all other STDs.

HHH, MD
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17 months ago
Thanks for the prompt reply. My concern was that I got tested a few weeks ago but it was not a first catch urine sample and I was told this makes the test unreliable. I urinated a few seconds in the toilet prior to filling cup. I was not given proper instructions. Does it have to be first catch to be accurate?  Thanks again
17 months ago
I thought that the penicillin was high dosage 2.4 million units? Thanks for answering my final questions. God bless 
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
17 months ago
First catch urine isn't all that important. It's the official advice, because that's the technique that was used when the urine gonorrhea/chlamydia tests were developed. But day to day use over the past 15-20 years shows it makes no difference.

The total amount of penicillin (2.4 million units) is large, but it's a kind of penicillin that remains in the muscle and leaches out into the blood very slowly, over 10-14 days, so blood and system levels are very low -- high enough for syphilis, which is extremely sensitive to penicillin. But not enough to have much effect on most other bacteria, including gonorrhea and chlamydia.
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