Antibodies, but negative? IgN IgA

Recently, a girl I had unprotected sex with said she had gone to the doctor for a yeast infection and found out in the process that she has clamydia (chlamydia) too.
I live in Japan, and it is hard to find a doctor who speaks English and you can trust.  So, before going to one, I got a blood test done for STDs.  I was negative for HIV and syphullis, but positive for the antibodies for clamydia (chlamydia). I went straight to a doctor that the clinic recommended, and he took a urine sample.
He informed me today that the test were negative and that i do NOT have clamydia (chlamydia).  
I am slightly very confused as to what is going on.   How do I test positive for the antibodies and not the disease since i have not had it before in the past to my knowledge?

[whatthef]

...and let me add (from reading the other posts on here), that it was 1st stream urine (not mid- as auntijessie always suggests), and i had waited hourssssss since the last pee in an effort to save some up.  so, if those are the major reasons why i would get a false negative....

..and thinking back...i did have some infection about 3 years ago, but the doctor just called it a urinary tract infection (not clamydia (chlamydia)) and gave me meds for that...i'm wondering now if that was what i really had?   would that explain the antibodies?

[auntiejessi]

That's tough to say, really.  I would go on the assumption that you need to be treated, and take meds as if you had it.

You might not ever really know, but the important thing is that everyone is tested and treated appropriately.

AJ

[whatthef]

yeah, i agree, but they won't give me meds unless it's positive.
doctors are awfullllll here.  
i'm gonna get re-tested at a different place this week and see.
thanks...

[Dallasfan]

Let me add that serum antibody levels are not , I repeat not the test you need to diagnose chlamydia. A urine or a swab test from the urethra is needed. Many of us have had repiratory illnesses caused by other strains of chlamydia giving a low positive on the IgG serum test. Since you had unprotected sex with a girl testing positive for chlamydia you should be treated and evaluated for other STDs. Take care.