: Chlamydia Antigen, Urine
: This test looks for proteins (antigens) from the bacterium Chlamydia trachomatis in a urine sample to help detect a chlamydia infection.
[": A positive result suggests chlamydia antigen is present, but antigen tests are less sensitive than modern molecular tests, so results should be interpreted with your clinician."]
Key facts at a glance
- LOINC
- 108569-5
- Short code
- CHLMUR
- Synonyms
- Chlamydia Ag Msmt Urth
- Category
- chemistry
- Sample
- serum
- Container
- Sterile Dacron or rayon-tipped swab in viral/chlamydia transport medium
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- male
- Age range
- 14–99 years
- Method
- Direct immunofluorescence assay (DFA) / Enzyme immunoassay (EIA)
- CPT
- 87320
- SNOMED
- 310659008
- Specimen volume
- One urethral swab specimen
- Stability
- Refrigerate at 2-8°C; process within 24-48 hours of collection. If delayed, freeze at -70°C or below.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–48 hours
- Order
- routine
: What This Test Measures
: The test detects antigens, which are surface components of the Chlamydia trachomatis bacterium. Finding these antigens in urine suggests that the bacteria are present in the genital or urinary tract.
: How the Sample Is Collected
: A urine specimen is collected in a sterile container, usually a "first-catch" sample (the first part of the urine stream), which is most likely to contain organisms from the urethra. No special preparation is typically needed unless your provider says otherwise.
: What Results Mean
: A positive result indicates that chlamydia antigen was detected and generally points to an active infection that should be evaluated and treated. A negative result makes infection less likely but does not completely rule it out, since antigen tests can miss some infections.
: Test Limitations
: Antigen-based tests are generally less sensitive than nucleic acid amplification tests (NAATs), which are the preferred method for chlamydia detection. Because of this, a negative antigen result may need confirmation with a molecular test if symptoms or exposure suggest infection.
Reference range
Negative: No Chlamydia sp. antigen detected. Positive: Chlamydia sp. antigen detected, indicating active infection.N/A
Patient should refrain from urinating for at least 1-2 hours prior to specimen collection. Avoid recent antibiotic use if possible. No fasting required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
: Chlamydia Antigen
Frequently asked questions
: Is this the same as a chlamydia NAAT test?
: Do I need to fast or prepare for this urine test?
: What should I do if my result is positive?
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