Chlamydia Antibody Detection by Immunoassay (Serum/Plasma)
This test checks for antibodies to *Chlamydia trachomatis*, a common bacterial infection that can affect the genitals, throat, or eyes. Antibodies develop after infection, helping your immune system fight it. This test is used to confirm past or recent exposure.
["Detects signs of past or recent *Chlamydia* infection through your blood or fluid sample."]
Key facts at a glance
- LOINC
- 45131-0
- Short code
- CHLMAGNP
- Synonyms
- Chlamydia Ag Nph Ql IF
- Category
- chemistry
- Sample
- serum
- Container
- Sterile viral transport medium or specific Chlamydia transport medium; nasopharyngeal swab in suitable transport container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Direct Immunofluorescence Assay (DFA)
- CPT
- 87810
- SNOMED
- 441914003
- Specimen volume
- 1 nasopharyngeal swab
- Stability
- Refrigerated (2-8°C): 24-48 hours. If testing is delayed beyond 48 hours, freeze at -70°C or below. Do not store at room temperature for extended periods.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Doctors may order this test if you have symptoms like unusual discharge, pain during urination, or unexplained pelvic pain. It’s also used for screening in high-risk groups, such as sexually active individuals with multiple partners or those with sexually transmitted infections (STIs). Some health plans may recommend it as part of routine check-ups.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample (usually from your arm) or a fluid sample (like saliva or urine, depending on the test). If you’re tested for antibodies, it’s typically done on serum or plasma from blood.
What the Test Results Mean
A positive result means your body has detected antibodies against *Chlamydia*, suggesting past infection. A negative result means no detectable antibodies were found at the time of testing. However, a negative result doesn’t always rule out infection—it may take weeks or months for antibodies to appear after exposure.
Possible Side Effects or Risks
Most people experience no side effects. Rarely, you might feel slight discomfort or bruising at the injection site. If you’re pregnant, discuss this test with your doctor, as it’s generally safe but may be part of routine STI screening.
Reference range
Negative: No Chlamydia sp. antigen detected. Positive: Chlamydia sp. antigen detected.N/A
No special patient preparation required. Specimen should be collected prior to administration of antibiotics when possible. Patient should not have eaten or drunk recently to avoid contaminating the nasopharyngeal sample.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Chlamydia Antibody Test
Frequently asked questions
Why might I need this test?
What does a positive result mean for my health?
Can I get this test if I’ve already been treated for *Chlamydia*?
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