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: Chlamydia trachomatis IgM Antibody, Serum (Qualitative)

Published: August 9, 2026Updated: August 16, 2026

: This test looks for IgM antibodies against Chlamydia trachomatis in a blood (serum) sample. It is a qualitative test that reports whether these antibodies are detected, not a specific amount.

Quick summary

[": A Chlamydia IgM result is interpreted together with symptoms and other tests, not on its own."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
21186-2
Short code
Chlamydia IgM Ser Ql
Synonyms
Chlamydia IgM Ser Ql
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 detects immunoglobulin M (IgM), a type of antibody the immune system can produce early after exposure to Chlamydia trachomatis. Because the result is qualitative, it indicates whether IgM antibodies are detected rather than giving a numeric level.

: Why It May Be Ordered

: A clinician may order this test as part of an evaluation for possible chlamydial infection, often alongside other laboratory tests. Antibody testing is not the preferred method for diagnosing active genital chlamydia, so results are usually considered in the context of the full clinical picture.

: How the Sample Is Collected

: A blood sample is drawn from a vein and the serum is separated for testing. No special preparation is usually needed, but follow any instructions from your clinician or laboratory.

: How Results Are Reported

: Results are typically reported as detected or not detected (sometimes called positive or negative) for IgM antibodies. A detected result does not by itself confirm an active infection, and a not-detected result does not rule one out.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

: Chlamydia IgM

Frequently asked questions

: Can this test tell me if I have an active chlamydia infection?
: Not reliably on its own. Antibody tests detect the immune response rather than the organism itself, so they cannot confirm an active infection by themselves. Direct tests such as nucleic acid amplification testing are generally used for that purpose.
: Does a detected IgM result always mean a recent infection?
: No. IgM results can be affected by timing, cross-reactivity, and individual immune responses, so a detected result must be interpreted with other clinical information.
: Do I need to fast before this blood test?
: Fasting is usually not required for this test, but follow any specific instructions given by your clinician or the laboratory performing the collection.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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