Test ID: MUMPS
Mumps Virus Antibody, IgG and IgM (Separate Determinations), Serum

Laboratory diagnosis of mumps virus infection

Detecting acute mumps infection

Mumps virus, together with parainfluenza virus, respiratory syncytial virus and measles virus are classified in the family Paramyxoviridae.

Mumps is an acute infection that causes painful enlargement of the salivary glands in 70% to 90% of children (4-15 years of age) who develop clinical disease. In 5% to 20% of postpubertal individuals, testicular pain (orchitis) and abdominal pain (oophoritis in females) can occur. Other complications include pancreatitis (<5% of cases) and central nervous system disease (meningitis/encephalitis) that occur rarely (about 1 in 6,000 cases of mumps).

Widespread routine immunization of infants with attenuated mumps virus has changed the epidemiology of this virus infection. Since 1989, there has been a steady decline in reported mumps cases, with an average of 265 cases each year since 2001. However, a recent outbreak of mumps in 2006 re-emphasized that this virus continues to persist in the population, and laboratory testing may be needed in clinically compatible situations.

The laboratory diagnosis of mumps is typically accomplished by detection of antibody to mumps virus. However, due to the limitations of serology (eg, inadequate sensitivity and specificity), additional laboratory testing including virus isolation or detection of viral nucleic acid by PCR in throat, saliva or urine specimens should be considered in clinically compatible situations.

IgG

Negative (reported as positive, equivocal, or negative)

IgG index value 0.00-0.89=negative

IgM

Negative (reported as positive, equivocal, or negative)

IgM index value 0.00-0.79=negative

See Virology in Special Instructions for additional interpretive information.

IgG:

Positive: presence of detectable IgG-class antibodies without IgM-class antibodies suggests response to immunization or infection with mumps virus at some time in the past. Individuals testing positive for IgG-class antibodies are considered immune to mumps virus infection.

Negative: absence of detectable IgG-class antibodies suggests lack of a specific immune response to immunization or no previous exposure to mumps virus.

IgM:

Positive: presence of IgM-class antibodies to mumps virus may support a clinical diagnosis of recent/acute phase infection with this virus.

Negative: absence of IgM-class antibodies suggests lack of an acute phase infection with mumps virus. However, serology may be negative in early disease, and results should be interpreted in the context of clinical findings.

Serum specimens obtained during the acute phase of infection may be negative by serological tests. Assay performance characteristics have not been established for matrices other than serum. All positive IgM results must be interpreted cautiously as some false-positive results or heterotypical responses of the IgM have been seen in the serum of pregnant women or in patients with an acute infection caused by cytomegalovirus, herpes simplex, measles, rubella, and parvovirus.

Determination of a post-immunization immune response or documentation of a previous infection should be accomplished using MMPG/82431 Mumps Virus Antibody, IgG, Serum. Testing for IgM-class antibodies to mumps virus should be limited to patients with a clinically compatible disease.

1. Hodinka RL, Moshal KL: In Essentials of Diagnostic Virology. Edited by GA Storch. Churchill Livingstone, New York, 2000, pp 168-178

2. Harmsen T, Jongerius MC, van der Zwan CW, et al:Comparison of a neutralization enzyme immunoassay and an enzyme-linked immunoassay for evaluation of immune status of children vaccinated for mumps. J Clin Microbiol 1992;30(8):2139-2144

• Virology