Chlamydia

If i tested positive for chlamydia and my partner gets tested and he is negitive. How could he be negitive if i am positive?

[H. Hunter Handsfield, M.D.]

This question comes up fairly frequently.  There are several potential explanations which I will summarize briefly. You should be able to find more additional discussions on the forum; use the search link and enter "chlamydia".  Some of these explanations may not necessarily apply in your case; you can judge for yourself.

1) He is infected but the test missed it. The modern chlamydia tests pick up about 90-95% of infections.  That's excellent but not perfect.  The test is most likely to miss an infection when urine is tested, less likely if a swab was collected from his urethra.

2) Your test was a false positive, i.e. you're not infected at all.  This is rare with modern chlamydia tests, but more common if your doctor and lab use an older kind of test.

3) Your partner was infected but it cleared up before his test was done.  Given enough time, chlamydia (and most infections in humans) go away on their own, even without treatment.

4) He was infected but took an antibiotic that cured him.  This could happen if he was treated specifically for chlamydia (and didn't tell you), or if he got an antibiotic for something else, like bronchitis or a skin infection.

5) He never was infected.  Chlamydia can be carried by women for many months, sometimes for a couple of years.  Maybe you brought the infection into the relationship from some past partner, and he never caught it.  If he had chlamydia in the past, he might be resistant to a new infection.  Or if you had a new partner recently and caught the infection from him, maybe your regular partner hasn't been exposed frequently enough to catch it yet.  STDs are not transmitted with 100% efficiency.

You might have other clues you haven't mentioned, that would help you judge these various possibilities.  For example, if you had a negative chlamydia test in the past, you would know you were infected since that time. If you want to describe the specific situation in a bit more, I might be able to help sort it out more accurately.  But regardless of the specific explanation, it important that your partner be treated now, regardless of his negative test -- in case of explanation no. 1.

Anyway, I hope this helps.  Best wishes--  HHH, MD

[lauran421]

I went in for my last pap and was tested then. That was about a year and three months ago. I went in for a pap bout a week ago and tested positive, but i have been with the same person for 3 years. In what you had wrote back could you really have something like this for that many years without any signs?

[H. Hunter Handsfield, M.D.]

It is possible you were infected at the time of your pap test 15 months ago and the test missed it.  But it isn't very likely.  Most infections go away without treatment in a few months to a year or two, and the longest a woman has ever been proved to carry chlamydia is 4 years.  Probably around 10% of infected women carry it for 3 years.  So in order to attribute your infection to your previous relationship, you have to have two unlikely events:  longer than expected carriage plus your test missing the infection 15 months ago.  The odds both those things happened are pretty low.  Therefore, it is more likely that you caught the infection sometime between your negative test and your positive one.

This of course assumes that your partner had another partner, got infected, gave it to you, the had a negative test himself.  Whether or not this is a likely explanation depends on things you can know and I cannot -- in other words, you are in a much better position than I am to judge whether he is likely to have had other partners.  If he has not, then there has to be another explanation -- perhaps the one I suggested above, or one of the other ones discussed in yesterday's response, such as your test being false negative.

Very often it just isn't possible to sort these things out with certainty.  A lot depends on your judgment of your partner's fidelity.  I suggest you give him the benefit of the doubt, but still have a forthright but sensitive (and non-blaming) conversation with him.  Or to use the nuclear weapons control terminology, "trust but verify".

Good luck--  HHH, MD