Measles Antibodies (IgG, IgM), Diagnostic
Also known as: Rubeola IgG and IgM Antibodies
Use
Serologic testing for measles-specific IgG is useful for assessing immunity from prior infection or vaccination, while detection of IgM antibody indicates recent or current infection. Results must be interpreted in context of timing relative to rash onset and may produce false positives or negatives. PCR testing of respiratory specimens may be preferred for confirming acute cases. Quest recommends collecting both serum for IgM/IgG and respiratory swabs for PCR in suspected measles, particularly early in disease course. Seroconversion or a ≥4-fold rise in IgM titer between acute and convalescent specimens supports diagnosis.
Special Instructions
Not provided.
Limitations
False-positive IgM results can occur, particularly in low-prevalence settings. IgM may be undetectable if serum is collected too early (e.g., <3 days after rash onset). IgG seroconversion may aid diagnosis when IgM is negative or inconclusive. Specimen timing critical for accurate interpretation. PCR remains gold-standard. Quest provides guidance to collect both serum and respiratory specimens to increase diagnostic sensitivity.
Methodology
Immunoassay
Biomarkers
Result Turnaround Time
Not provided.
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
Not provided
Minimum Volume
Not provided
Collection Instructions
Collect serum (acute-phase) as soon as possible; if initial negative and PCR negative/not reported, collect second serum 3–10 days after symptom onset. Also collect throat or nasopharyngeal swab for PCR.
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