Chlamydia IgM Antibody (Serum) – Immunoassay
This test detects antibodies in your blood that your immune system produces in response to the chlamydia bacteria, a common sexually transmitted infection.
["Helps diagnose past or current chlamydia infection by identifying immune system response."]
Key facts at a glance
- LOINC
- 110789-5
- Short code
- Chlamydia IgA Msmt Ser
- Synonyms
- Chlamydia IgA Msmt Ser
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82784
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
The test uses an immunoassay method to identify IgM antibodies specific to chlamydia. These antibodies develop after your body has been exposed to the bacteria, usually within a few weeks to months after infection. The presence of these antibodies suggests a past infection, though they may not always indicate an active infection at the time of testing.
Why It Might Be Ordered
Your healthcare provider may order this test if you have symptoms of chlamydia (such as unusual discharge, pain during urination, or pelvic pain) or if you’ve been exposed to the infection. It’s also sometimes used as part of screening for sexually transmitted infections.
Sample Collection and Preparation
A blood sample is drawn from a vein in your arm. The blood is then processed to separate the serum, which is sent to a lab for testing. This test requires no special preparation, but fasting is not required.
What to Expect Before the Test
You may experience mild discomfort or bruising at the injection site, but most people tolerate blood draws well. If you have a clotting disorder or are on blood-thinning medication, let your provider know before the test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
IgM Antibody to Chlamydia (Serum)
Frequently asked questions
Chlamydia IgM antibodies can indicate past infection, but they may not always reflect an active infection. Positive results suggest exposure, but they do not confirm current infection without additional testing (such as culture or nucleic acid amplification). IgM levels can also decrease over time, so repeated testing may be needed for diagnosis.
What does a positive result mean? A positive IgM test indicates your body has likely been exposed to chlamydia, but it does not always mean you have an active infection. Your provider may recommend further testing, such as a culture or PCR test, to confirm current infection status.
Does this test detect all types of chlamydia? This test specifically detects IgM antibodies against chlamydia trachomatis, the most common cause of chlamydia. Other strains may require different antibody testing.
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