Mumps – Diagnostic Serology

Testing Indications

When Mumps infection is suspected - Contact your local Public Health Ontario Laboratory to ensure that appropriate testing is requested and inform your local Public Health Unit of all probable or suspect cases of mumps.

Diagnosis for symptomatic patients or post exposure, requires additional samples for testing by PCR, refer to the test information sheet Mumps-Diagnostic PCR for specimen collection and testing information.

Specimen Collection and Handling

Specimen Requirements

Test Requested Required Requisition(s) Specimen Type Minimum Volume Collection Kit

Mumps Diagnosis

Whole blood or serum

5.0 ml whole blood or 1.0 ml serum

Blood, clotted - vacutainer tubes (SST)

Mumps Diagnosis

Plasma

1.0 ml

Lavender top tube

Submission and Collection Notes

1

Test performed will be Mumps IgG and IgM if date of onset and clinical symptoms are indicated on the General Test Requisition Form.

Timing of Specimen Collection

Acute: Collect the acute sample within 7 days after the onset of symptoms.

Convalescent: Collect the convalescent sample 7 to 10 days after the acute.

Limitations

Hemolysed, icteric, lipemic or microbially contaminated sera or plasma are not recommended for testing.

Preparation Prior to Transport

Label the specimen container with the patient’s full name, date of collection and one other unique identifier such as the patient’s date of birth or Health Card Number. Failure to provide this information may result in rejection or testing delay.

Special Instructions

Centrifuge if using SST. Place specimen in biohazard bag and seal. Specimens should be stored at 2-8°C following collection and shipped to PHOL on ice packs.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Mumps diagnostic serology to detect Mumps IgG and IgM is performed daily Monday to Saturday.

Turnaround time for test results is up to 5 days from receipt by PHO laboratory.

Reporting

Results are reported to the ordering physician or health care provider as indicated on the requisition.

Specimens that are positive for Mumps are to be reported to the Medical Officer of Health as per Health Protection and Promotion Act.

Test Methods

The Mumps IgM and IgG tests are performed using ELISA (Enzyme Linked Immunosorbent Assay) test kits manufactured by Euroimmun Diagnostics (Germany). The IgM and IgG ELISA tests measure human antibodies of the IgM and IgG classes against mumps virus in serum or plasma. Test results are reported qualitatively together with a clinical interpretation based on the status of both IgM and IgG.

Interpretation

After a primary infection, both IgM and IgG antibodies develop within 3-7days after onset of mumps specific symptoms. Both antibodies subsequently increase reaching a plateau 2-3 weeks later.

Antibody levels may be reported as Non-Reactive (no detectable antibody), Indeterminate (the level of antibody detected is considered borderline reactive or equivocal) or Reactive (antibody is detectable within the positive range of the assay). 

Non-Reactive and Indeterminate levels of both IgM and IgG antibodies may be observed in the acute stage of infection rising to reactive levels in subsequent weeks. 

In the absence of acute infection indeterminate levels of IgG may represent very low levels of antibody many years after initial infection or vaccination whereas indeterminate levels of IGM may be due to declining levels of IGM several months post infection or occasionally due to assay non-specificity.

If the acute blood sample shows low reactive, indeterminate or non reactive IgG result and/or IgM result, a convalescent sample should be collected. Recent infection is confirmed if a significant rise in antibody levels is observed between acute and convalescent sera.

Mis à jour le 4 janv. 2019