Skip to content

Mycoplasma pneumoniae Antibody, Qualitative (IgM) - Serum/Plasma

Published: August 9, 2026Updated: August 17, 2026

This test detects the presence of IgM antibodies against *Mycoplasma pneumoniae*, a bacterium that can cause respiratory infections like pneumonia or bronchitis.

Quick summary

["Helps diagnose recent *Mycoplasma pneumoniae* infections, often linked to lung or ear infections."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
20902-3
Short code
Mycoplas+Ureoplas Tiss Ql Cult
Synonyms
Mycoplas+Ureoplas Tiss Ql Cult
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
organism-specific-culture
CPT
84484
SNOMED
302774002
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 Is This Test For?

This test checks for IgM antibodies, which appear shortly after infection. IgM antibodies are typically the first immune response to a new infection, making them useful for identifying recent exposure to *Mycoplasma pneumoniae*.

How Is the Sample Collected?

A blood sample is drawn from a vein in your arm. The blood is sent to a lab for testing. This test is usually done on serum or plasma, the liquid part of blood without or with clotting factors removed.

What Does a Positive Result Mean?

A positive result suggests recent infection with *Mycoplasma pneumoniae*. However, false positives can occur, so additional testing or clinical correlation may be needed. IgM antibodies typically decline over weeks to months as the body produces longer-lasting IgG antibodies.

What Does a Negative Result Mean?

A negative result means no detectable IgM antibodies were found in this sample. This could mean you haven’t been infected recently, or the infection may have already resolved. It doesn’t rule out past exposure or chronic infection.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Mycoplasma pneumoniae IgM Antibody (Serum/Plasma)

Frequently asked questions

Why might your doctor order this test?
Your doctor may recommend this test if you have symptoms like cough, fever, or ear pain, especially if other tests (like a throat culture) are inconclusive. It helps confirm a recent *Mycoplasma pneumoniae* infection, which can be difficult to diagnose without specific antibodies.
How long does it take to get results?
Results are typically available within 24 to 72 hours, depending on lab processing times. Follow-up with your healthcare provider to discuss the results and next steps.
Can this test be used for long-term monitoring?
No, this IgM test is primarily for detecting recent infections. For long-term monitoring of *Mycoplasma pneumoniae* or other chronic conditions, other tests (like IgG antibodies or PCR) may be used instead.
  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 17, 2026. · Read our editorial policy