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 Fluid (CSF) for Subacute sclerosing panencephalitis (SSPE) refer to:

Measles Serology TIS

Updates:

As of October 6, 2025, the multi-jurisdictional Measles outbreak has been declared over in Ontario. Measles PCR is the recommended diagnostic test for patients under Measles investigation.
Removed NML genotyping criteria

* Copie d'impression non contrôlée. Valide uniquement le jour de l'impression : 28 nov. 2025.

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.

Measles molecular testing (PCR) is the preferred diagnostic test as it provides early detection, high sensitivity and specificity and the ability to differentiate between wild-type and vaccine strains. Measles serology testing may provide additional diagnostic and epidemiological value. The decision to collect blood for serology remains at the discretion of the health care provider or public health unit.

Testing for immune status (IgG) is not routinely recommended for individuals who are unvaccinated, under-vaccinated, or with unknown vaccination status. Measles-containing vaccine should be offered as the ideal protective measure in accordance with Canadian Immunization Guide.

For suspected cases of Measles, contact your local public health unit (PHU) prior to collecting specimens.

Acceptance/Rejection Criteria

Specimens received in incorrect containers or expired kits will be rejected.

Specimen Collection and Handling

Specimen Requirements

Test Requested	Required Requisition(s)	Specimen Type	Minimum Volume	Collection Kit
Measles Virus Diagnosis	General Test Requisition	Nasopharyngeal swab^3,4	1 swab in transport media contained in kit	Nasopharyngeal Collection Kit for Viral PCR order#: 390082
Measles Virus Diagnosis	General Test Requisition	Throat swab^3,5	1 swab in transport media contained in kit	Large Swab Throat Collection Kit for Viral PCR order#: 390081
Measles Virus Diagnosis	General Test Requisition	Urine^3,6	Minimum volume 10mL	Sterile container

Submission and Collection Notes

Complete all fields of the requisition form, including:

Test(s) requested and indications for testing
Patient setting
Clinical information (symptoms, symptom onset date, and number of days from rash onset to collection), MMR/MMRV vaccination status and travel history (including date of travel/return).

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 either a nasopharyngeal (NP) swab or throat swab for PCR testing, as well as a blood specimen for serology testing. Collecting a urine specimen along with an NP/throat swab may improve sensitivity of testing. 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 Centre at 416-235-6556 or 1-877-604-4567.

Timing of Specimen Collection

Nasopharyngeal swab 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.

Individuals exhibiting prodromal symptoms without a rash, who have a strong epidemiologic link to a confirmed case, may be tested. Result should be interpreted with caution.

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.

To assist with laboratory workflow and identifying specimens for priority testing, send Measles specimens separate from routine specimens and mark STAT on the outside of the package.

Requisitions and Kit Ordering

Test Frequency and Turnaround Time (TAT)

Test	Turnaround Time	Test Location	Frequency	Sample receipt cut-offs*
Measles Multiplex PCR	Up to 3 business days from receipt at PHO Laboratory	Toronto	Monday to Saturday	11AM
Measles Multiplex PCR	Up to 3 business days from receipt at PHO Laboratory	Hamilton London Ottawa Kingston Timmins Thunder Bay	Monday to Friday	11AM^a
Measles full Genotype (NML)	Up to 21 days from the receipt at NML	National Microbiology Laboratory	N/A	N/A

*Specimen must arrive at PHO’s laboratory testing site at the time listed in this column to be included in the same day testing, specimens that arrive later than time listed will be tested on the next available run.

^aSpecimen received after 11am on Friday in London, Hamilton, Ottawa, Kingston, Timmins and Thunder Bay will be directed to Toronto for testing on Saturday .

STAT and Critical Specimens Testing

Refer to the above cut-off hours in the ‘Frequency and turnaround time’ section for priority specimen testing.

Critical measles testing for vulnerable populations/patient settings may be available outside of regular hours upon special request and approval from a PHO microbiologist. For consultation, 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.

Test Methods

Measles diagnosis assay is performed using polymerase chain reaction (PCR) – Laboratory developed test validated at PHO’s laboratory; not Health Canada approved. This assay detects measles targets (H1, F1 and N3) and measles vaccine strain.

Algorithm

Specimens will be tested using the measles multiplex PCR test that detects 3 viral targets (H1, F1 and N3) of the measles virus and confirms if it is measles vaccine strain (Genotype A).

The multiplex test is available in Toronto, Hamilton, London, Ottawa, Kingston, Thunder Bay and Timmins.

All specimens in which one or more of the Measles viral targets are detected, and the measles vaccine target is not detected (implying a wild-type virus), will be referred to the NML for genotyping.

Refer to the NML for more information on measles genotyping.

Interpretation

Measles multiplex assay: results will be reported as DETECTED, NOT DETECTED, INDETERMINATE, or INVALID for each of the three measles virus targets and measles vaccine target

Result	Interpretation
Detected	Measles virus target(s) and/or measles vaccine target detected by real-time PCR
Not Detected	Measles virus target(s) and measles vaccine target not detected by real-time PCR Note: a negative result does NOT exclude the possible presence of measles virus in the patient.
Indeterminate	An indeterminate test result may be due to a low level of target genetic material in the specimen, inadequate specimen content, or a non-specific signal. Please submit another specimen for testing if clinically indicated.
Invalid	INVALID results indicate failed amplification of the extraction control which may be due to inadequate specimen content, extraction failure, or PCR inhibition. It is recommended to resubmit another specimen for testing if clinically indicated

This result must be interpreted within the context of the clinical history and epidemiological information.

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.

Information for Health Care Providers

NOTE: Measles: Information for Health Care Providers

* Copie d'impression non contrôlée. Valide uniquement le jour de l'impression : 28 nov. 2025.

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customerservicecentre@oahpp.ca

Mis à jour le 24 nov. 2025