Rubella – Diagnostic (Molecular Testing by RT–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.
Background
This page provides PCR and genotyping testing information for Rubella Virus.
Rubella PCR is a referred out test. Specimens are sent to the National Microbiology Lab (NML) in Winnipeg.
A positive rubella RT-PCR result in the absence of recent immunization is laboratory confirmation of rubella virus infection.
For information regarding other testing options, refer to the following PHO webpages:
Updates
- Updated the frequency of PHO shipment to NML
- Updated the NML test turnaround times
Testing Indications
Laboratory testing of a suspect case of rubella should include acute and convalescent serology as well as virus detection. Refer to the Test Information Sheet, Rubella Diagnostic Serology for specimen collection and testing information.
Acceptance/Rejection Criteria
Please visit Molecular Detection and Genotyping - Guide to Services - CNPHI (canada.ca)
Specimen Requirements
| Test Requested | Required Requisition(s) | Specimen Type | Minimum Volume | Collection Kit |
Rubella virus |
Throat/ nasopharyngeal swab |
1 swab in transport media contained in kit |
Virus Respiratory Kit order#: 390082 |
|
Rubella virus |
Urine |
50 mL (minimum 10 mL) |
Sterile container |
|
Rubella virus |
Aborted material, placenta or autopsy material |
1.0 gram |
Sterile container or for small pieces, in the transport media of Virus Respiratory Kit order#: 390082 |
Submission and Collection Notes
A nasopharyngeal swab can be collected in addition to a throat swab or can serve as an alternative specimen for infants with Congenital Rubella Syndrome (CRS). Congenitally infected infants may shed the virus in the urine and in nasopharyngeal secretions for 1 year or more.
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. Failure to provide this information may result in rejection or testing delay.
Complete all fields of the General Test Requisition Form, including:
- The patient’s full name, date of birth, Health Card Number (must match the specimen label)
- The test requested, source of specimen, and date of collection
- Clinical signs and symptoms (e.g. rash), date of onset, and diagnosis
- Date of last rubella vaccination (if recent), travel history, rubella exposure history, and/or MARS identifier (Measles, Rubella and CRS/CRI Surveillance, CNPHI) as available
Timing of Specimen Collection
The rubella virus can be detected in the oropharynx 2-3 days before rash and up to 7 days post rash. The optimal timing for virus detection is the day of rash through day 5 post rash:
Nasopharyngeal (NP), throat swabs or urine should be collected as soon as possible after rash onset (within 7 days). Note: specimens collected later will still be accepted however the assay sensitivity will not be optimal.
For congenital rubella cases, collect urine, NP or throat swabs within the first few months after birth. Viral isolates may also be sent.
Other specimen types may be accepted; please contact the PHO CSC prior to submission.
Storage and Transport
Throat and NP swabs may be stored and shipped refrigerated (2-8°C) to PHO’s laboratory within 48h of specimen collection. If shipping is delayed longer than 48h the specimens must be stored in the freezer (-70°C) and shipped with dry ice. Fresh biopsies must be always stored frozen and shipped on dry ice. Do not freeze unprocessed urine.
All clinical specimens must be shipped in accordance to the Transportation of Dangerous Good Act.
Special Instructions
Place specimen in biohazard bag and seal.
Test Frequency and Turnaround Time (TAT)
Rubella virus PCR is forwarded to NML once per week. Stat testing available upon request.
NML TAT– Detection: 7 calendar days; Genotyping: 21 calendar days, upon receipt at NML
STAT and Critical Specimens Testing
For urgent cases, contact the PHO’s laboratory Customer Service Center prior to submitting specimens.
Molecular detection of the rubella virus is achieved by real-time RT-PCR amplification followed by genotyping of positive specimens.
Rubella virus RNA extracted from samples is amplified by real-time RT-PCR targeting the E1 and p150 genes (4). A portion of the E1 gene of positive samples is amplified by conventional RT-PCR and a WHO standardized region of the E1 glycoprotein (739 nucleotides) is sequenced to determine the genotype of the rubella virus (1-3).
For additional information, refer to Molecular Detection and Genotyping - Guide to Services - CNPHI (canada.ca)
Interpretation
A positive rubella RT-PCR result is laboratory confirmation of rubella virus.
Reporting
Results are reported to the physician, authorized health care provider (General O. Reg 45/22, s.18) or submitter as indicated on the requisition.
Specimens that are positive for Rubella are reported to the Medical Officer of Health as per Health Protection and Promotion Act.
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