Cytomegalovirus – Detection – Real Time 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 PCR testing information for Cytomegalovirus (CMV) detection at Public Health Ontario (PHO). For information regarding other testing options, refer to the following PHO webpage:
Testing Indications
The CMV qualitative PCR is of use in the following clinical scenarios:
- Evaluation of a newborn for congenital CMV infection
- Screening for CMV disease in immunocompromised patients or critically ill (e.g. admitted to ICU) immunocompetent patients where CMV disease is suspected
Positive qualitative PCR tests should be followed up with a quantitative CMV PCR test, which is not available at PHO’s laboratory. Testing these patients with a quantitative test as the primary testing approach is preferred if available.
Acceptance/Rejection Criteria
Blood/serum specimens will not be accepted for CMV PCR testing.
Specimen Requirements
| Test Requested | Required Requisition(s) | Specimen Type | Minimum Volume | Collection Kit |
Cytomegalovirus PCR |
Bronchio-alveolar lavage (BAL)/bronchial wash |
2.0 ml |
Sterile container |
|
Cytomegalovirus PCR |
Urine |
2.0 ml |
Sterile container |
|
Cytomegalovirus PCR |
CSF |
400 µl |
Sterile container |
|
Cytomegalovirus PCR |
Tissue (e.g. Lung) |
1.0 gram |
Sterile container |
|
Cytomegalovirus PCR Confirmation of CMV DNA detection on newborn screen test. |
Urine |
2.0 ml |
Sterile container |
Submission and Collection Notes
Complete all fields of the requisition form, including:
- Test(s) requests and indications for testing
- Patient setting/population/source
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: Criteria for Acceptance of Patient Specimens. Failure to provide this information may result in rejection or testing delay.
Place specimen in biohazard bag and seal.
Limitations
Cerebral spinal fluid (CSF) specimens have not been validated with this assay, but can be tested and reported with a disclaimer
Storage and Transport
Specimens should be stored at 2-8°C following collection and shipped to PHO’s laboratory on ice packs. If transport is delayed for more than 72 hours, store at -80°C and ship on dry ice .
All clinical specimens must be shipped in accordance to the Transportation of Dangerous Good Act.
Test Frequency and Turnaround Time (TAT)
Cytomegalovirus PCR is performed Monday, Tuesday and Thursday at PHO’s laboratory.
Turnaround time for CMV real-time PCR is up to 3 business days from receipt at PHO’s laboratory.
Specimens are tested for CMV by real-time PCR (qualitative real-time PCR using Altona RealStar® CMV PCR Kit 1.0). This commercial assay is not Health Canada approved but has been validated at PHO’s laboratory for qualitative detection of CMV DNA in clinical specimens. The manufacturer has reported a limit of detection of 0.668 IU/ml (95% CI 0.323 to 2.258 IU/ml) using the ABI 7500 FAST SDS system.
Algorithm
If detection of respiratory viruses is requested on the same specimen, additional testing will be done depending on the patient setting (respiratory virus testing is currently only routinely available for inpatients and patients being tested as part of an outbreak investigation).
Interpretation
Results will be reported as DETECTED/ NOT DETECTED/ INDETERMINATE for CMV.
The presence of CMV DNA in a sample does not always imply active infection; the diagnosis of CMV infection must be made using a combination of clinical suspicion, physical exam and detection of virus.
Indeterminate results are reflective of a signal detected during late rounds of amplification in the real time PCR reaction. This could represent a low quantity of CMV DNA in the specimen, or may be a nonspecific reaction giving a false signal. For indeterminate results, consider resubmitting another specimen if clinically indicated.
Reporting
Results are reported to the ordering physician, authorized health care provider (General O. Reg 45/22, s.18) or submitter as indicated on the requisition.
CSF specimens that are positive for cytomegalovirus are reported to the Medical Officer of Health as per the Ontario Health Protection and Promotion Act.
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