[Question #7260] Accuracy of Chlamydia Test After 3 Days

6 months ago
19 days ago, I had unprotected sex. It was with a U.S.-based escort, whose rates were very expensive.  Exactly 70 hours later, I had a urine chlamydia and gonorrhea test from Quest Diagnostics. When I took the test, I had last urinated about 90 minutes before the test. 

The results were negative.

However, this morning I noticed a sharp burning sensation in my penis while urinating. I have no discharge, and have not experienced any other symptoms prior to this. I did masturbate immediately before urinating, and I suppose that could have caused it, but it is not common for me to have pain after masturbating. I also noticed that my urine was very yellow (which is unusual for me), so I drank lots of water afterwards. I have urinated a few times since then, and have not felt any burning.

After taking this test, I saw a prior response from Dr. Handsfield in which he recommended waiting longer than 3 days for a chlamydia test.

My questions:

1. Exactly how accurate are chlamydia tests 3 days after exposure? (A percentage or range of percentages is what I'm looking for,  if the data exists.)

2. If I do have chlamydia, should I expect the pain in urinating to persist? In other words, if I don't experience pain the rest of the day or tomorrow, should I take comfort in that?

Thank you :)
Edward W. Hook M.D.
Edward W. Hook M.D.
6 months ago
Welcome to our forum.  I’ll be glad to comment.  Before I get to the specifics of test performance, let me point out that here in the U.S. most commercial sex workers do not have STIs.  They tend to get checked regularly,  further I should point out that most single exposures to infected partners do not lead to infection.  

Currently available tests for Gonorrhea and chlamydia are amongst the most sensitive tests in all of medicine.  There are no data on precisely how long it takes for tests to become positive following infection but research studies of experimental infections show that Gonorrhea is detectable within 24 hours of acquisition.  On a theoretical basis, Chlamydia may take slightly longer but a 70 hour test should be entirely reliable.  I urge you to believe your test results.

The pain you experienced upon urination this morning is unlikely to be an STI.  When symptoms occur due to STIs, the persist and do not occur intermittently. Thus, in answer to your questions:

1.  See above. I would be entirely confident in these test results 
2.  Yes, if you had chlamydia or any other STI I would expect continued symptoms 

I hope this information is helpful.  EWH