Lab Testing for Mumps at the MDH Public Health Laboratory

Though mumps is no longer common in the United States, outbreaks continue to occur as a result of internationally imported or import-linked cases. Continued success in disease reduction is dependent on maintaining awareness of the disease along with improving vaccination rates.  

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Report suspect mumps cases
Clinical case definition

Clinical materials
Specimen collection: PCR
Approved swabs and media
Specimen collection: Serologic testing
Laboratory results and interpretation
Transporting specimens to MDH

Report suspect mumps cases

If you suspect mumps in a patient, report the suspect case by:

  • Calling MDH at 651-201-5414 or toll-free at 1-877-676-5414 to provide clinical details

or

Health care facilities are required to report suspect cases of mumps within one working day to MDH.

Clinical case definition

An acute illness characterized by parotitis/other salivary gland swelling (lasting at least 2 days), orchitis or oophoritis unexplained by another more likely diagnosis.

Clinical materials

Specimens for reverse transcriptase polymerase chain reaction (RT-PCR) testing and a blood specimen should be collected from all patients who meet the clinical case definition for mumps.

Submit PCR specimens to MDH-PHL, and serum sample to your usual reference laboratory. If submission to reference lab is not possible, contact MDH to discuss other options.

Specimen collection: PCR

Clinical specimens for RT-PCR should be obtained within five days of parotitis onset (0-9 days at most). Consider parotitis onset date as day “0.” The type and number of specimens sent varies based on when swelling began:

  • On day 0-5 of swelling, collect a buccal swab*
  • On day 6-9 of swelling, collect a buccal swab and a urine specimen

*If a buccal swab cannot be collected, a throat swab can be sent instead; however, a buccal swab is preferred.

Buccal swab: Massage the buccal cavity (the space near the upper rear molars between the cheek and the teeth) for 30 seconds and swab the area; obtain a generous amount of saliva. Place swab in a sterile tube containing 2-3 ml of viral transport medium (VTM)

Throat swab: Vigorously swab tonsillar areas and posterior nasopharynx with a viral culturette. Use tongue blade to depress tongue to prevent contamination of swab with saliva. Place swab into VTM.

Urine specimen: Collect 10 ml of urine in a sterile urine specimen container. First-morning voided specimens are ideal, but any urine collection is adequate. Have patient void directly into container, collecting from the first part of the urine stream if possible.

Approved swabs and media

Appropriate

  • BBL Culture Swab, Culturettes
  • VTM , M5, M4, MEM, Saline, Balanced salt solutions (BSS), Sterile isotonic solutions, Phosphate buffered salines (PBS), Stuart’s Liquid Media

Not Appropriate

  • Wood-tipped applicators, Calcium-alginate tipped swabs, Charcoal swabs, Gel swabs
  • Anaerobic media

Specimen collection: Serologic testing

Collect 7-10 ml of blood in a red top tube or serum separator tube (SST).

  • Draw blood for IgM antibody testing immediately after onset of parotitis.
  • If initial testing is negative and mumps is strongly suspected, a convalescent serum sample should be collected 2-3 weeks after symptom onset.

Laboratory results and interpretation

Results for RT-PCR testing done at MDH-PHL will be sent via fax to the submitting laboratory.

RT-PCR:

  • Positive RT-PCR or culture confirms mumps.
  • PCR may be positive if the individual was vaccinated in the 6-45 days prior to onset.  This would not be considered a true mumps infection and the individual is not infectious. Consult with MDH as testing may be considered if the patient has also had a relevant exposure to mumps.
  • Negative is inconclusive, as vaccinated individuals may shed virus for a shorter period and might shed smaller amounts of virus.

IgM: Results should be interpreted with caution as false positive and negatives are possible.

  • A positive result in an asymptomatic patient is inconclusive.
  • Mumps IgM results may be falsely positive due to known cross-reactivity with other viruses and agents, including parainfluenza, Epstein-Barr, adenovirus, human herpesvirus-6 and certain antibiotics.

IgG: A single serum sample tested for mumps-specific IgG is not useful for diagnosing acute mumps infections.

Transporting specimens to MDH

  • Label all tubes/containers with:
    • Patient name
    • Patient date of birth
    • Date specimen collected
    • Specimen type
  • Include an Infectious Disease Testing and Submission Form with each specimen submitted.
  • Fill out the form as completely as possible and be sure to indicate which test is requested.
  • Specimens must be kept and transported at refrigeration temperature
    (2-8° C).
  • Before shipping, always consult with an MDH epidemiologist at 651-201-5414 or 877-676-5414.
  • Send to MDH-PHL via overnight shipping.
  • For help with packaging and shipping, call MDH-PHL Biological Accessioning at (651) 201-4953.

Send specimens to arrive Monday-Friday before 4:30 p.m. to:
MDH Public Health Laboratory
Attn: Biological Accessioning
601 Robert St. N.
St. Paul, MN 55155-2531

Updated Wednesday, February 10, 2016 at 12:54PM