Chlamydia IgG Antibody (Serum/Plasma) – Immunoassay
This test detects antibodies in your blood that your immune system produces in response to *Chlamydia trachomatis*, a common bacterial infection. It helps identify past exposure to the bacteria, even if you no longer have symptoms.
["This test checks for past infection, not current illness, by measuring antibodies your body made to fight Chlamydia."]
Key facts at a glance
- LOINC
- 45010-6
- Short code
- Chlamydia IgG CSF Ql
- Synonyms
- Chlamydia IgG CSF Ql
- Category
- chemistry
- Sample
- csf
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82784
- Specimen volume
- 1-2 mL
- Stability
- Immediate analysis required, Refrigerated: 1h
- Hemolysis max
- 200
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Doctors may order this test if you have risk factors for Chlamydia, such as new or multiple sexual partners, unprotected sex, or symptoms like unusual discharge, pain during urination, or pelvic pain. It’s also used in screening for sexually transmitted infections (STIs) in certain populations.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm in a clinic or lab. If you’re tested as part of a routine screening, your doctor may ask about recent sexual activity or symptoms.
What the Test Results Mean
A positive result means your body has produced IgG antibodies against Chlamydia, suggesting past infection. However, this does not confirm an active infection—active Chlamydia is diagnosed with a different test (e.g., nucleic acid amplification). A negative result means no detectable antibodies were found.
Possible Side Effects
Minor side effects from blood drawing may include slight bruising, swelling, or discomfort at the injection site. Rarely, a reaction to the needle or blood draw can occur.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
IgG Antibody to Chlamydia (Serum/Plasma)
Frequently asked questions
This test is critical for identifying past exposure to Chlamydia, which can help guide counseling about sexual health, prevent reinfection, and inform decisions about future screening. Unlike IgM antibodies (which indicate recent infection), IgG antibodies persist longer and are useful for tracking exposure over time.
IgG antibodies can remain in your system for months or years after infection. If you’re sexually active, regular STI screening (including this test) is recommended, especially if you have risk factors.
No, this test does not show whether you currently have Chlamydia. For active infection, tests like PCR (Polymerase Chain Reaction) or culture are used instead.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy