Chlamydia Antibody Test (Serum or Plasma) – Immunoassay
This test detects antibodies in your blood that may indicate past or possible exposure to *Chlamydia trachomatis*, a common bacterial infection often spread through sexual contact. It helps healthcare providers assess infection risk or confirm exposure.
["This test may be used if you have symptoms or risk factors for chlamydia or as part of routine screening."]
Key facts at a glance
- LOINC
- 109551-2
- Short code
- CHLAG-A
- Synonyms
- Chlamydia Ag Msmt Anal
- Category
- chemistry
- Sample
- serum
- Container
- Sterile transport container or swab transport medium specific for Chlamydia testing
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 14–100 years
- Method
- Enzyme immunoassay (EIA) or Nucleic acid amplification test (NAAT) for Chlamydia antigen detection
- CPT
- 87320
- SNOMED
- 441910008
- Specimen volume
- 1 swab or 1 mL of anal/rectal specimen in appropriate transport medium
- Stability
- Room temperature: 2 hours; Refrigerated (2-8°C): 24-48 hours; Frozen (-70°C): up to 30 days
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
Why This Test Matters
Chlamydia is a bacterial infection that can affect the reproductive system, eyes, or throat. While some people may not experience symptoms, untreated infections can lead to serious health issues like pelvic inflammatory disease, infertility, or complications during pregnancy. Antibody tests help identify past exposure, which can inform preventive or treatment decisions.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample (serum or plasma) via a simple venipuncture. If testing urine, you may be asked to collect a midstream sample. Results are typically available within 2–5 business days.
What the Test Results Mean
A positive result suggests your body has produced antibodies against chlamydia, indicating past exposure. A negative result means no detectable antibodies were found at this time. Antibody tests cannot confirm *active* infection (which would require culture or nucleic acid amplification testing).
When You Might Need Follow-Up
If you receive a positive antibody result, your healthcare provider may recommend additional testing (e.g., PCR) to check for active infection. They may also advise retesting in 3–6 months to monitor antibody levels, as they can decline over time.
Reference range
Negative: No Chlamydia trachomatis antigen detectedN/A
No fasting required. Patient should refrain from using rectal medications, enemas, or douches for 24 hours prior to specimen collection. Avoid sexual intercourse 24 hours before sample collection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Chlamydia Antibody Screening
Frequently asked questions
What are the typical symptoms of chlamydia?
Can this test detect active chlamydia infection?
How long do chlamydia antibodies stay in the blood?
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