What are the diagnostic tests for mumps (infectious parotitis)?

From the Guidelines

The most effective diagnostic approach for mumps involves a combination of clinical evaluation and laboratory tests, with the most reliable test being a swab from the parotid duct or buccal mucosa near the affected salivary gland, which should be collected within the first few days of symptom onset for optimal results, as supported by the 2018 update by the Infectious Diseases Society of America and the American Society for Microbiology 1.

Diagnostic Tests for Mumps

The diagnostic tests for mumps include:

• Blood tests to detect mumps-specific IgM antibodies, which appear early in the infection
• Viral cultures or RT-PCR tests performed on samples collected from the throat, urine, or cerebrospinal fluid
• Swabs from the parotid duct or buccal mucosa near the affected salivary gland, which are the most reliable samples for diagnosis
• Urine samples, although less sensitive, may be positive for at least 5 days after detection in the mouth

Importance of Early Diagnosis

Early diagnosis of mumps is crucial to prevent further transmission of this contagious viral infection and to ensure appropriate management. Healthcare providers should consider clinical symptoms such as parotid gland swelling, fever, headache, and muscle aches when making a diagnosis. In some cases, imaging studies like ultrasound may help evaluate gland inflammation.

Laboratory Tests

Laboratory tests, including serology, culture, and nucleic acid amplification tests (NAAT), can be used to diagnose mumps. The preferred specimen source for culture and/or NAAT is an oral or buccal swab around the affected parotid gland and Stensen duct, as stated in the 2018 update by the Infectious Diseases Society of America and the American Society for Microology 1. Mumps virus RNA may be detected prior to onset of parotitis until 5–9 days after symptom onset.

Clinical Evaluation

Clinical evaluation is also essential in diagnosing mumps, as the disease can sometimes be confused with other conditions that cause similar swelling. A combination of clinical evaluation and laboratory tests can help healthcare providers make an accurate diagnosis and ensure appropriate management and public health measures to prevent further transmission of this contagious viral infection, as discussed in the management of suspected viral encephalitis in adults and children 1.

From the Research

Diagnostic Tests for Mumps

The diagnostic tests for mumps (infectious parotitis) include:

• Molecular methods:
  • Reverse transcription polymerase chain reaction (RT-PCR) to detect viral nucleic acid 2
  • RT-PCR allows for diagnosis with maximum sensitivity and can also be used for genotype characterization by sequencing the SH gene
• Serological methods:
  • Enzyme-linked immunosorbent assay (ELISA) to detect IgM and IgG antibodies 3, 4, 5
  • Focus reduction neutralization test (FRNT) to detect neutralizing antibodies 3
  • IgM detection is considered the gold standard for mumps diagnosis, but may not always be elicited in highly vaccinated populations 2
• Other methods:
  • Isolation of virus 6
  • Detection of viral nucleic acid 6

Comparison of Diagnostic Tests

• The concordance between mumps RT-PCR and IgM EIA is highest during the first 2-5 days and decreases with increasing time post-onset 3
• Mumps FRNT results agree with those of RT-PCR/IgM EIA from the second week onwards, whereas the results of mumps IgG EIA agree with those of RT-PCR/IgM EIA from post-onset days 3-10 3
• IgM capture ELISA is more reliable than indirect IgM ELISA, as it is less prone to false positive and false negative reactions 5