Antibody to Chlamydia trachomatis, IgG (Serum/Plasma)

What This Test Measures

IgG antibodies are part of your immune system’s long-term defense. If you’ve been exposed to Chlamydia trachomatis, your body may produce these antibodies over time. This test checks for their presence in your serum or plasma to determine if you had an infection at some point, even if symptoms were mild or absent.

Why It’s Done

Doctors may order this test if you have symptoms of a sexually transmitted infection (STI), such as unusual discharge, pain during urination, or pelvic pain in women. It’s also used as a screening test for Chlamydia in certain populations, like sexually active young adults or those with multiple sexual partners.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood, which usually takes a few minutes. If you’re pregnant or have a history of bleeding disorders, let your healthcare provider know before the test.

What the Results Mean

Positive results indicate the presence of IgG antibodies, suggesting past exposure to Chlamydia trachomatis. However, this does not confirm an active infection—it only shows your body’s immune response. If you’re concerned about an active infection, your doctor may recommend additional testing.