Anti-Mumps IgM is an indicator of recent or current infection with Mumps virus.
Indications for Testing
· Differential diagnosis of parotitis, orchitis, meningitis, and deafness
Mumps virus, together with parainfluenza types 1 through 4, respiratory syncytial virus, and measles virus are classified in the family Paramyxovirdae. Mumps is an acute infection which causes the painful enlargement of the salivary glands in approximately 70% to 90% of children (4-15 years of age) who develop clinical disease. In 5% to 20% of postpubertal individuals, testicular pain (orchitis in males) 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 and average of 265 cases each year since 2001. However, a recent outbreak of mumps in 2006 re-emphasized that this virus continued to persist in the population, and laboratory testing may be needed in clinically compatible situations.
When mumps was a common disease of childhood, the diagnosis was made largely on clinical grounds alone. With the decrease in incidence of mumps, many physicians no longer readily recognize the symptoms. In addition, typical clinical signs and symptoms may be absent in under immunized or immunocompromised individuals. Therefore, laboratory confirmation of mumps virus infection is now more important in making the diagnosis.
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.
Reactive: A reactive result may occur with a recent mumps infection or after vaccination. In the majority of cases IgM remain detectable up to 5 months post infection. Not all mumps virus infections with detectable virus-specific IgM cause clinical symptoms.
Non-reactive: A non-reactive result does not exclude early active infection. If clinically indicated submit a follow-up specimen. Anti-mumps IgM may not be detected in previously vaccinated individuals. To confirm active infection virus detection is recommended.
Indeterminate: Specimen produced results near the cut-off (indeterminate), please submit a follow up specimen ≥1 week to resolve.
Litman, N., and Baum, S. G. 2010. Mumps Virus, p. 2201-2206. In Mandell, D., Bennett, J. E., and Dolin, R. Principles and practice of infectious diseases, 7th ed., vol. 2. Churchill Livingstone, Elsevier, Philadelphia, PA.
Leland, D. S. 2007. Parainfluenza and Mumps Viruses, p. 1352-1360. In Murray, P. R., Baron, E. J., Jorgensen, J. H., Landry, M. L., and Pfaller, M. A. Manual of Clinical Microbiology, 9th ed., vol. 2. ASM Press, American Society for Microbiology, Washington, DC.
Siemens. 2008. Enzygnost® Anti-Parotitis-virus/IgM: package insert. Siemens Healthcare Diagnostics Products GmbH.