Measles – Immunity Serology

Testing Indications

Serology for Measles Immunity Serology (Measles IgG) may be indicated to determine immune status (either following natural infection or post-vaccination).

Diagnostic requests for symptomatic patients or post exposure, refer to the test information sheets Measles-Diagnostic PCR, and Measles-Diagnostic Serology for specimen collection and testing information.

Specimen Collection and Handling

Specimen Requirements

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

Measles Immunity

Whole blood or serum

5.0 ml blood or 1.0 ml serum

Blood, clotted - vacutainer tubes (SST)

Measles Immunity

Plasma

1.0 ml

Lavender top tube

Submission and Collection Notes

1

The test performed will be Measles IgG

2

Check the box marked “Immune Status” on the General Test Requisition Form when immune status testing is required. Do not check “Diagnostic” or both boxes. If “Diagnostic” is ticked   both IgG and IgM testing will be performed.  IgM is not needed for the determination of immune status as it is a marker of acute infection.

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 PHO laboratory on ice packs.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Measles Immunity serology to detect Measles IgG is performed daily Monday to Saturday.

Turnaround time 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.

This test is a qualititative test. Quantitative results will ONLY be provided when the reason for testing is for the determination of immunity / immune status and this is clearly indicated on the PHO laboratory requisition. If diagnosis is indicated or ticked quantitative IgG results will not be reported.

Test Methods

The Measles IgG test is performed using an ELISA (Enzyme Linked Immunosorbent Assay) test kit manufactured by Euroimmun Diagnostics (Germany). This ELISA test provides a quantitative in vitro assay for human antibodies of the IgG class against measles  virus in serum or plasma. 

Measles IgG test results are reported both qualitatively (Non-Reactive, Indeterminate or Reactive) and quantitatively together with an interpretation of the patient’s immune status based on the level of measles IgG detected.

The unit of measles IgG antibody measurement is mIU/ml (milli international  units/millilitre).

Interpretation

Measles IgG Antibody Ranges and Result Interpretation:

  • Non-reactive (<1200 mIU/ml): No Evidence of Immunity (indicates susceptibility)
  • Indeterminate (≥200 - <275 mIU/ml): Antibody levels in the indeterminate range for this assay may be insufficient to confer immunity.
  • Reactive (≥275 mIU/ml): Evidence of past infection / vaccination; evidence of immunity.

These interpretations assume the absence of acute or recent infection

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Laboratory Services

customerservicecentre@oahpp.ca

Updated 4 Jan 2019