Measles – Diagnostic – PCR
Consistent with O. Reg. 671/92 of the French Language Services Act, laboratory testing information on this page is only available in English because it is scientific or technical in nature and is for use only by qualified health care providers and not by members of the public.
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:
- Updated to include other testing sites at PHO’s laboratory and operation hours for priority testing requests.
- Updated testing algorithm, only specimens that are not detected on the Measles vaccine PCR assay (positive for Measles by PCR) will be referred to NML for genotyping.
Testing Indications
Measles PCR is a diagnostic test for the detection of viral RNA in clinical specimens collected from patients suspected of having Measles and is useful during the early phase of the disease following symptom onset.
For suspected cases of Measles - contact your local public health unit (PHU) prior to collecting specimens and notify PHO’s Laboratory Customer Service Centre prior to submitting STAT measles specimen(s) to our laboratory.
Acceptance/Rejection Criteria
Specimens received in incorrect containers or expired kits will be rejected.
Specimen Requirements
| Test Requested | Required Requisition(s) | Specimen Type | Minimum Volume | Collection Kit |
Measles Virus Diagnosis |
Nasopharyngeal swab4 |
1 swab in transport media contained in kit |
Virus Respiratory Kit order#: 390082 |
|
Measles Virus Diagnosis |
Throat swab5 |
1 swab in transport media contained in kit |
Virus Culture Kit order#: 390081 |
|
Measles Virus Diagnosis |
Urine6 |
Minimum volume 10mL |
Sterile container |
Submission and Collection Notes
Complete all fields of the requisition form, including:
- Test(s) requests and indications for testing
- Patient setting
- Clinical information (symptom and symptom onset), MMR/MMRV vaccination status and travel history (including date of travel/return).
- Indicate whether the local PHU was notified of the case.
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.
For diagnosis of symptomatic patients, collect NP and/or throat, as well as urine specimens and blood for serology. See next section for the recommended timing of specimen collection.
Refer to the Nasopharyngeal Specimen Collection Instructions for collecting nasopharyngeal swab specimens.
Refer to the Throat Specimen Collection Instructions for collecting throat swab specimens.
Urine specimen collected in other media (i.e. CTNG specimen container) will be rejected for testing.
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 of rash onset.
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.
Test Frequency and Turnaround Time (TAT)
| Test | Turnaround Time | Test Location | Frequency | Sample receipt cut-offs* |
|---|---|---|---|---|
|
Measles PCR |
Up to 3 business days from receipt at the PHO’s laboratory |
Toronto
Hamilton |
Monday to Saturday
Monday to Friday |
11AM |
| Measles Vaccine Genotype PCR | Up to 3 business days after the confirmation of Measles PCR positive at any of the PHO’s laboratory sites | Toronto | Monday to Saturday | N/A |
| Measles full Genotype (NML) | Up to 21 days from the receipt at NML | National Microbiology Laboratories | N/A | N/A |
*Samples must arrive at PHO’s laboratory at time listed in this column to be included in the same day testing, if samples arrive later than time listed here it will be tested in the next available run
STAT and Critical Specimens Testing
Priority testing is available outside of regular hours stated in “Frequency and turnaround time” section above.
Please contact PHO’s laboratory Customer Service at 416-235-6556/1-877-604-4567 or after-hours, contact the Duty Officer at 416-605-3113 for consultation with and approval by PHO’s laboratory Microbiologist.
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, all negative in-house measles vaccine genotype PCR will be referred to NML for full genotyping
Refer to NML for more information - https://cnphi.canada.ca/gts/reference-diagnostic-test/4996?labId=1016.
Interpretation
Results will be reported as DETECTED/NOT DETECTED/INDETERMINATE for measles virus PCR.
- 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.
Results will be reported as DETECTED/NOT DETECTED for measles vaccine genotype PCR.
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