Chlamydia Antibody Screening by Serologic Immunoassay (Serum/Plasma)
This test detects antibodies in your blood that may indicate past or current infection with *Chlamydia trachomatis*, a common sexually transmitted bacterium. It helps healthcare providers assess exposure risk and guide treatment decisions.
["This screening helps identify potential infection without requiring active symptoms."]
Key facts at a glance
- LOINC
- 16590-2
- Short code
- CHL-CFT
- Synonyms
- Chlamydia Ab Ser CF-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum tube or serum separator tube (SST)
- Units
- N/A
- Ref low
- 10
- Ref high
- 1
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- comp-fix
- CPT
- 86631
- SNOMED
- 10828004
- Specimen volume
- 1-2 mL of serum
- Stability
- Serum stable at 2-8°C for 7 days; for longer storage, freeze at -20°C or below. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 24–72 hours
- Order
- routine
Why This Test Is Done
Your doctor may recommend this test if you have symptoms like unusual discharge, pain during urination, or if you’ve been exposed to *Chlamydia* through sexual contact. It’s also part of routine screening for sexually active individuals at higher risk, such as those with multiple partners or recent partners with unknown infection status.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample (usually drawn from your arm) in a serum or plasma tube. The test is quick and typically done in a clinic or lab setting.
How the Test Works
The test uses an immunoassay method to detect specific antibodies (immunoglobulins) your immune system produces in response to *Chlamydia*. These antibodies may appear weeks to months after infection.
What the Results Mean
A positive result suggests past or current infection. A negative result means no detectable antibodies at the time of testing, but you may still be at risk if exposed recently. Follow-up testing or additional questions may be needed.
Reference range
Negative: <1:10 titer; Equivocal: 1:10-1:20; Positive: ≥1:40 titer. Results are reported as the highest dilution of serum demonstrating complement fixation activity.N/A
No fasting required. Avoid hemolyzed or lipemic specimens as they may interfere with complement fixation testing. Patient should be informed about the test purpose and provide relevant clinical history including symptoms and potential exposure.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Chlamydia Antibody Screen
Frequently asked questions
What does a positive result mean?
Can I get treated if my test is positive?
Do I need to avoid sex during treatment?
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 15, 2026. · Read our editorial policy