IgG antibody detection is a marker for a Chlamydia-positive immune- response, either for current, chronic or past infections. For a reliable interpretation of results both IgG and IgA antibodies must be tested.

How long do Chlamydia IgG last?

A third published study dealt with the long-term persistence of serum Chlamydia IgG antibodies in patients with high initial IgG antibody titres (≥1:128) in serum after pelvic inflammatory disease (Puolakkainen et al., 1986). The follow-up time was between 3.1 and 6.3 years.

What does Chlamydia IgM positive mean?

A positive IgM and/or IgA result together with a significant increase in the IgG titer of a follow-up sample taken after an interval of at least two weeks indicate an acute infection. Reinfections are charac- terised by an increase in the IgA and/or IgG titer in the ab- sence of an IgM response.