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HelpTest Code MYCOM Mycoplasma pneumoniae Antibodies, IgM, Serum
Reporting Name
M. pneumoniae Ab, IgM, SUseful For
Screening for IgM antibodies in the indication of recent or past exposure to Mycoplasma pneumoniae
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| MMYCO | M. pneumoniae Ab, IgM, S by IFA | No | No |
Method Name
Only orderable as part of a profile. For more information see MYCO / Mycoplasma pneumoniae Antibodies, IgG and IgM, Serum.
Enzyme Immunoassay (EIA)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen Required
Only orderable as part of a profile. For more information see MYCO / Mycoplasma pneumoniae Antibodies, IgG and IgM, Serum.
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 14 days | |
| Frozen | 14 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Rejected |
| Heat inactivated specimen | Reject |
Reference Values
Only orderable as part of a profile. For more information see MYCO / Mycoplasma pneumoniae Antibodies, IgG and IgM, Serum.
Negative
Day(s) Performed
Monday through Friday
CPT Code Information
86738
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| MYCOM | M. pneumoniae Ab, IgM, S | 5257-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| MYCOM | M. pneumoniae Ab, IgM, S | 5257-1 |
Secondary ID
48318Clinical Information
Mycoplasma pneumoniae is a small bacterium transmitted via organism-containing droplets. It is a cause of upper respiratory infection, pharyngitis, and tracheobronchitis, particularly in children, and has been associated with approximately 20% of cases of community-acquired pneumonia. Central nervous system and cardiac manifestations are probably the most frequent extrapulmonary complications of infections due to M pneumoniae. The disease is usually self-limited, although severe disease has been reported in immunocompromised patients.
Identification of M pneumoniae by culture-based methods is time consuming and insensitive. Serology-based assays for M pneumoniae have several drawbacks. The development of IgM antibodies takes approximately 1 week, and the IgM response may be variable in adults or decreased in immunosuppressed individuals. Confirmation of the disease is dependent on the observation of a 4-fold rise in IgG antibody titers between acute and convalescent specimens, several weeks following the initial onset of illness, providing clinical utility only for retrospective testing. Real-time polymerase chain reaction offers a rapid and sensitive option for detection of M pneumoniae DNA from clinical specimens for diagnosis of acute or current infection.
Interpretation
|
IgG ELISA Result |
IgM ELISA Result |
Interpretation |
|
Positive |
Negative |
Results suggest past exposure. |
|
Positive
|
Reactive |
Prior exposure to Mycoplasma pneumoniae detected. Confirmatory testing for IgM to M pneumonia will be performed by an immunofluorescence assay. |
|
Equivocal |
||
|
Negative |
Negative |
No antibodies to M pneumoniae detected. Acute infection cannot be ruled out as antibody levels may be below the limit of detection. If clinically indicated, a second serum should be submitted in 14 to 21 days. |
|
Negative |
Reactive |
No prior exposure to Mycoplasma pneumoniae. Confirmatory testing for IgM to M pneumonia will be performed by an immunofluorescence assay. |
|
Equivocal |
||
|
Equivocal |
Negative |
Recommend follow-up testing in 10 to 14 days if clinically indicated. |
|
Reactive |
Confirmatory testing for IgM to M pneumonia will be performed by an immunofluorescence assay. |
|
|
Equivocal |
ELISA = Enzyme-linked immunosorbent assay
Cautions
A diagnosis of Mycoplasma pneumoniae infection should not be solely based on results of serologic testing for this agent. Test results should be interpreted in conjunction with clinical evaluation and the results of other diagnostic procedures (eg, molecular detection).
The continued presence or absence of antibodies cannot be used to determine the success or failure of therapy.
Testing should not be performed as a screening procedure for the general population. Testing should only be done when clinical evidence suggests the diagnosis of M pneumoniae-associated disease.
The performance of this test has not been established on neonates and immunocompromised patients.
Performance of the IgM assay has not been tested with specimens known to be positive for antibodies to organisms that are known to be associated with lower respiratory illness (ie, influenza A and B, cytomegalovirus, Chlamydophila pneumoniae, parainfluenza), and closely related serovars known to cross-react with M pneumoniae, such as M genitalium and M hominis, as well as various Ureaplasma species. Cross-reactivity studies with such organisms have not been performed with this assay.
The IgG removal system included with the IgM test system has been shown to functionally remove the IgG from specimens containing total IgG levels ranging from 300 to 600 mg/mL. The effectiveness of this removal system at IgG levels exceeding 600 mg/mL has not been established.
Clinical Reference
1. Smith T: Mycoplasma pneumoniae infections: diagnosis based on immunofluorescence titer of IgG and IgM antibodies. Mayo Clin Proc 1986 Oct;61(10):830-831
2. Holzman RS, Simberkoff MS, Leaf HL: Mycoplasma pneumoniae and atypical pneumonia. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Elsevier; 2020:2332-2339
Method Description
IgM Enzyme Immunoassay:
Test sera are diluted with the sample diluent provided. The sample diluent contains antihuman IgG that precipitates and removes IgG and rheumatoid factor from the sample, leaving IgM free to react with immobilized antigen. Diluted sera are incubated in antigen-coated microwells. Any antigen-specific antibody in the samples will bind to the immobilized antigen. The plate is washed to remove unbound antibody and other serum components. Peroxidase-conjugated goat-antihuman IgM (chain specific) is added to the wells and incubated. The conjugate will react with the IgM antibody/antigen on the solid phase. The wells are washed to remove unbound conjugate. The microwells containing immobilized conjugate are incubated with peroxidase substrate solution. Hydrolysis of the substrate by peroxidase produces a color change. After a period of time the reaction is stopped by the addition of diluted acid, and the color changes are measured photometrically. The color intensity of the solution depends on the antibody concentration in the serum sample.(Package insert: M pneumoniae IgM Test System. Zeus Scientific, Inc; Revision Date 9/22/2016)
IgM Immunofluorescence Assay:
Mycoplasma pneumoniae antigenic substrate is fixed onto microscope slide wells. Serum that has been pretreated to remove IgG antibodies is incubated with the substrate. If IgM antibody to M pneumoniae is present, it will bind to the substrate. Fluorescein-labeled antihuman-IgM conjugate is added to the slide wells, and the slide is incubated. If antibody is present, it can be observed as a characteristic positive, bright, apple-green fluorescent reaction when the slide is read on a fluorescence microscope.(Package insert: Mycoplasma pneumoniae IgM IFA Antibody Test System. Zeus Scientific, Inc; 09/2019)