Chlamydia Trachomatis Nucleic Acid Test (Conjunctival Swab)
This test checks for the presence of *Chlamydia trachomatis*, a bacteria that can cause eye infections, including conjunctivitis (pink eye). It uses a sample taken from your conjunctiva (the thin tissue covering the white part of your eye and inside your eyelids).
["This test helps diagnose eye infections caused by a specific bacteria that may require treatment with antibiotics."]
Key facts at a glance
- LOINC
- 109438-2
- Short code
- CHLACONJ
- Synonyms
- Chlamydia Ag Msmt Conjunct
- Category
- chemistry
- Sample
- serum
- Container
- Sterile transport swab (Dacron or rayon-tipped) in viral transport medium (VTM) or Chlamydia transport medium
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Immunochromatographic assay; Direct fluorescent antibody (DFA); Enzyme immunoassay (EIA)
- CPT
- 87810
- SNOMED
- 167230008
- Specimen volume
- Adequate conjunctival scraping or swab specimen (minimum sufficient material to detect antigen)
- Stability
- Refrigerate at 2-8°C if testing within 24-48 hours; freeze at -70°C or below for prolonged storage; transport on wet ice
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–48 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may recommend this test if you have symptoms like red, swollen, or itchy eyes, discharge, or pain. It’s also used in certain high-risk groups, such as sexually active individuals or those with known exposure to sexually transmitted infections (STIs).
How the Test Works
A healthcare professional will gently collect a sample from your conjunctiva using a sterile swab. The swab is then sent to a lab, where genetic material from *Chlamydia trachomatis* is detected using a specialized nucleic acid amplification test. This method is highly sensitive and can identify the infection even if symptoms are not present.
Sample Collection Process
The sample is quick and painless. You may feel a slight tugging sensation, but it won’t cause discomfort. The swab is inserted into your eye or eyelid, and the sample is collected. No special preparation is needed, but avoid touching your eyes or using eye drops before the test if instructed otherwise.
What to Expect After the Test
After the test, you may experience mild redness or irritation in your eye, which usually goes away on its own. Avoid rubbing your eyes or applying pressure to the area. Follow any additional instructions from your healthcare provider.
Reference range
Negative for Chlamydia sp antigenN/A
No special preparation required. Avoid topical application of eye drops, ointments, or anesthetics for at least 1 hour prior to specimen collection. Do not irrigate the eye before sampling.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Chlamydia Eye Infection Test
Frequently asked questions
How long does it take to get results?
What are the possible results?
Can I have this test if I’m pregnant?
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