Measles – Diagnostic – PCR

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This page provides diagnostic polymerase chain reaction (PCR) testing information for Measles at Public Health Ontario (PHO). For information regarding other testing options, including Cerebral Spinal Fluvid (CSF) for Subacute sclerosing panencephalitis (SSPE) refer to:

Updates:

  • Effective September 09, 2023, new analysis Measles Vaccine Genotype PCR will be implemented to test all positive specimens from the measles PCR assay to distinguish the vaccine strain.

Testing Indications

For suspected cases of Measles - contact the PHO’s Laboratory or your local public health unit (PHU) prior to collecting specimens.

Specimen Collection and Handling

Specimen Requirements

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

Measles Virus Diagnosis

Nasopharyngeal swab3

1 swab in transport media contained in kit

Virus Respiratory Kit order#: 390082

Measles Virus Diagnosis

Throat swab4

1 swab in transport media contained in kit

Virus Culture Kit order#:  390081

Measles Virus Diagnosis

Urine

50.0 ml

Sterile container

Submission and Collection Notes

1

Complete all fields of the requisition form, including:

  1. Test(s) requests and indications for testing
  2. Patient setting/population/source
  3. Clinical information
  4. Indicate whether the local PHU was notified about the case
2

For clinical specimens, label the specimen container(s) with the patient’s first and last name, date of collection, and one other unique identifier such as the patient’s date of birth or Health Card Number. For additional information see: Specimen Acceptance Criteria.

Failure to provide this information may result in rejection or testing delay.

3

Refer to the Nasopharyngeal Specimen Collection Instructions for collecting nasopharyngeal swab specimens.

4

Refer to the Throat Specimen Collection Instructions for collecting throat swab specimens.

5

For submission of other specimen types please contact PHO’s laboratory customer service at 416-235-6556 or 1-877-604-4567.

Timing of Specimen Collection

Nasopharyngeal swab or aspirate and/or a throat swab should be collected within 7 days after onset of rash.

Urine should be collected within 14 days of rash onset and submitted in a sterile container.

In certain situations, such as when there is a high index of suspicion for measles (e.g. compatible illness in a returned traveler or contact of a laboratory confirmed case), it may be warranted to test beyond the above time periods when specimens could not be collected earlier in the illness. This can be discussed with PHO’s laboratory on a case by case basis.

Storage and Transport

Place specimen in biohazard bag and seal. Specimens should be stored at 2-8°C following collection and shipped to PHO’s laboratory on ice packs.

All clinical specimens must be shipped in accordance to the Transportation of Dangerous Good Act.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Measles PCR is performed daily Monday to Friday. TAT for Measles PCR is up to 3 business days of receipt at PHO’s laboratory.

Positive PCR specimens are sent for Measles Vaccine Genotype PCR.

TAT for MEA_VAC_PCR is up to 3 days after the confirmation of Measles positive at PHO’s laboratory.

All positives will be referred to National Microbiology Laboratory (NML) for full genotyping, TAT is 21 days

STAT and Critical Samples Testing

Measles PCR testing is not routinely performed after hours. In special circumstance where after hours/weekend testing may be warranted please contact the after hour’s emergency duty officer at 416-605-3113.

Test Methods

Measles diagnosis is performed using polymerase chain reaction (PCR) – Laboratory developed test validated at PHO’s laboratory; Not Health Canada approved.

Measles Vaccine Genotype is performed using polymerase chain reaction (PCR) – Laboratory developed test validated at PHO’s laboratory; Not Health Canada approved.

Algorithm

Positive measles PCR will be tested first in-house with measles vaccine genotype PCR, simultaneously all positives will be referred to NML for full genotyping

Refer to NML link - https://cnphi.canada.ca/gts/reference-diagnostic-test/4996?labId=1016

Interpretation

Results will be reported as DETECTED/NOT DETECTED/INDETERMINATE for measles virus.

  • For Indeterminate results, consider resubmitting another sample if clinically indicated.
  • This result must be interpreted within the context of the clinical history and epidemiological information.
  • A negative result does NOT exclude the possible presence of measles virus.

Reporting

Results are reported to the physician, or authorized health care provider (General O. Reg 45/22, s.18) or submitter as indicated on the requisition.

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

Mis à jour le 26 sept. 2023