The **Anti-Chlamydia trachomatis IgG antibody test** is a serological assay used to detect past or chronic exposure to *Chlamydia trachomatis*, a common bacterial sexually transmitted infection.
Unlike IgM or PCR tests that identify active, acute infections, the presence of **IgG antibodies** indicates a long-term immune response. Because chlamydial infections are frequently asymptomatic, they can remain undetected for years. High or persistent IgG titers are clinically valuable for investigating long-term complications of untreated chlamydia, such as pelvic inflammatory disease (PID), fallopian tube damage, ectopic pregnancy, and unexplained infertility in women, or epididymitis in men.