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Immunoglobulin M (IgM) Antibody to Mycoplasma pneumoniae

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

This test measures antibodies in your blood that your immune system produces in response to an infection by *Mycoplasma pneumoniae*, a type of bacteria that can cause respiratory illnesses like pneumonia.

Quick summary

["Helps identify past or recent infection with *Mycoplasma pneumoniae* that may cause lung or respiratory symptoms."]

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

Key facts at a glance

LOINC
106812-1
Short code
IgM BldCo IA-mCnc
Synonyms
IgM BldCo IA-mCnc
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
CPT
82784
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What This Test Measures

IgM antibodies are part of your immune system’s immediate response to infection. This test detects these antibodies to help determine if you’ve been exposed to *Mycoplasma pneumoniae* recently.

Why It’s Ordered

Your healthcare provider may order this test if you have symptoms like cough, fever, or shortness of breath, especially if other tests (like a chest X-ray or culture) are inconclusive or if you’ve been exposed to someone with *Mycoplasma pneumoniae* infection.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from a vein in your arm. If you’re concerned about needles, let your healthcare provider know.

What the Results Mean

Positive results suggest recent infection, while negative results indicate no recent exposure or an immune system that hasn’t yet produced detectable antibodies. Results alone don’t confirm diagnosis—your provider will consider symptoms, medical history, and other test results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgM Anti-Mycoplasma pneumoniae

Frequently asked questions

How long does it take to get results?
Results are typically available within 1–3 business days, depending on lab processing times. Follow up with your healthcare provider for interpretation.
Can I take antibiotics before getting this test?
Yes, if you’re prescribed antibiotics, take them as directed. Stopping them abruptly may affect test accuracy, so always follow your provider’s instructions.
Does this test differentiate between past and current infection?
IgM antibodies decline over weeks to months after infection, so they’re useful for recent exposure. IgG antibodies (not measured here) may be tested later to assess long-term immunity or past exposure.
  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