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Beaumont Laboratory

Mycoplasma pneumoniae IgM

Mycoplasma (IgM), Mycoplasma pneumoniae IgM, Antrim #15961, EPIC: LAB7085, SOFT: MYCMG

Specimen Collection Criteria

Collect: One Gold-top SST tube.

Physician Office/Drawsite Specimen Preparation

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged collection tube within two hours of collection. (Min: 0.5 mL)

Preparation for Courier Transport

Transport: Centrifuged collection tube, refrigerated (2-8°C or 36-46°F). (Min: 0.5 mL)

Rejection Criteria

  • Plasma specimens.
  • Severely lipemic, icteric, or hemolyzed specimens. 


Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers® with Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 8 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers® without Separator Gel
Room Temperature (20-25°C or 68-77°F): 2 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 2 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 1 year

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days


Royal Oak Special Testing Laboratory.


Tuesday, Thursday.
Results available in 3 business days.

Reference Range

Less than 0.91: Negative.
0.91 - 1.09: Equivocal.
Greater than 1.09: Positive.

Test Methodology

Enzyme-Linked Immunosorbent Assay (ELISA).


M. pneumoniae IgM is first detectable 7-14 days after the onset of symptoms. M. pneumoniae IgM testing early in the disease may yield false-negative results. The presence of M. pneumoniae IgM antibodies suggests current or recent infection. However, M. pneumoniae IgM antibodies may persist for more than 12 months post-infection or immunization.

Clinical Utility

IgM testing is used to provide serological evidence of a current M. pneumoniae infection. Negative results do not rule out the presence of M. pneumoniae-associated disease. If testing is performed too early following primary infection, IgM may not be detectable.

Clinical Disease

M. pneumoniae is primarily a respiratory tract pathogen that involves the nasopharynx, throat, trachea, bronchi, bronchioles, and alveoli. M. pneumoniae accounts for approximately 20% of all cases of pneumonia. Infected patients present with an insidious onset of fever, malaise, headache, and nonproductive cough. The frequency and severity of the cough often increases over 1-2 days and may eventually become debilitating. Most infections are self-limiting and are rarely fatal. However, serious cardiovascular, dermatologic, and central nervous system complications have been described.


Mycoplasma infections occur throughout the year, especially in temperate climates. Symptomatic infections occur most commonly in children and young adults (ages 2-19 years).

Incubation Period

The incubation period is 2 - 3 weeks (average = 15-25 days).


M. pneumoniae is spread from patient to patient via respiratory droplets produced by coughing.

CPT Code


Test Codes

Antrim #15961, EPIC: LAB7085, SOFT: MYCMG

Last Updated


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This directory currently reflects information only for specimens collected and/or processed at the Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.