Guidelines updated October 27, 2021.
Modifications are highlighted
COVID-19 Testing Policy and Guidelines
This document is adopted from the Public Health Ontario guidelines and other Health Unit guideline resources to instruct COVID-19 testing process and practice for the Erie St. Clair and South West health region.
Who to test:
Refer to the COVID-19 Provincial Testing Guidance Update on the Ministry of Health website for descriptions of individual categories and testing guidance. Click here for more information. As of August 25, 2021, asymptomatic screening testing is generally not recommended for individuals who are fully vaccinated.The following should be considered for COVID-19 molecular testing:
- Symptomatic individuals
Contacts of confirmed positive cases (regardless of vaccination status) within 10 days of their last exposure Asymptomatic workers and residents at specific outbreak sites may be considered for testing at the direction of public health
What Samples to Collect:
For detailed collection instructions and videos visit the Public Health Ontario Laboratory website. Follow the specimen type links under "Specimen Collection and Handling". Click here for more information.
For hospitalized patients with respiratory symptoms:
- Collect one nasopharyngeal swab in viral transport medium
- Nasopharyngeal specimens are the PREFERRED choice for swab-based SARS-CoV-2 testing
- Collection of a nasopharyngeal swab should be guided by the experience and comfort of the healthcare professional. Swab types with a flexible shaft and a small tip are ideal but may not be available for use
For in-patients, one additional lower respiratory sample can be collected, if clinically warranted:
- Expectorated sputum; do NOT induce sputum specimen
- Tracheal aspirate
- Bronchoalveolar lavage; do NOT perform bronchoscopy unless medically indicated
- Ensure collection traps are replaced by a screw-cap lid on specimen containers
When collection of a nasopharyngeal specimen is not possible, the following are ACCEPTABLE swab collection sites:
- Throat/oropharyngeal combined with both anterior nares/nostril specimen
For non-hospitalized patients with respiratory symptoms or asymptomatic persons meeting criteria outlined by the Ministry of Health:
- Collect one nasopharyngeal swab in viral transport medium
- Nasopharyngeal specimens are the PREFERRED choice for swab-based SARS-CoV-2 testing
- Collection of a nasopharyngeal swab should be guided by the experience and comfort of the healthcare professional. Swab types with a flexible shaft and a small tip are ideal but may not be available for use
- When collection of a nasopharyngeal specimen is not possible, the following are alternate PREFERRED swab collection sites:
- Throat/oropharyngeal combined with both anterior nares/nostril specimen
- Deep nasal specimen
- Oral (buccal) combined with deep nasal swab
- Salia (neat) collected in a Spectrum device
- When a preferred specimen site cannot be collected, the following are ACCEPTABLE collection sites:
- Throat/oropharyngeal specimen
- Anterior nares/nasal/nostril (both sides)
- Lower respiratory tract specimens
How to Order
- Thames Valley Cerner Sites
- In Powerchart, proceed to order COVID or COVIDSCR as appropriate
- Complete the COVID Screening PowerForm by populating the required fields, and click the "Sign" button
- A paper requisition does not need to be completed
- Specimens to be routed to PaLM Microbiology for testing
- Hosptial Sites electronically interfaced with Thames Valley Cerner
- Order COVID-19 testing, as per local LIS procedure
- Specimens to be routed to PaLM Microbiology for testing
- Webform Users
- Submit a COVID order by completing the webform
- Print and include a hardcopy of the resultant submission form with the specimen
- Specimens to be routed to PaLM Microbiology for testing
Ensure that the specimen tube is labeled properly and that the cap is screwed firmly to prevent leaking and test cancellation. Place specimen in biohazard bag and seal. Specimens should be stored at 2 to 8C following collection and transported either to the designated referral laboratory.
What is the Test Turnaround Time
Specimens processed in PaLM Microbiology:
- Testing will be performed 7 days a week
- The majority of reports will be issued within 24 hours of receiving the specimen in PaLM Microbiology
- Those requiring additional testing will be completed within 48 hours of being received
- All testing in this stream is CRITICAL by eligibility and treated as STAT on the next available run. There is no need to call to prioritize, as all needs are processed as STAT.
How will the Test be Reported
Do NOT call the PaLM Microbiology laboratory for results. Significant human resources are in place to manage reporting and verbal notification of these results within 24 hours of specimen receipt.
Thames Valley Cerner Sites
- Reports will be available in Cerner
- Positive COVID19 results for inpatients will be verbally communicated to the MRP/clinical unit by PaLM Microbiology
- Positive and Indeterminate COVID-19 final results will be reported to the appropriate Health Unit by PaLM Microbiology
Hospital sites electronically interfaced with Thames Valley Cerner
- Hardcopy Reports will be delivered by fax, or established printer connections, to the referring hospital laboratory indicated on the COVID-19 requisition
- Positive COVID19 results will be verbally communicated to the referring hospital laboratory contact by PaLM Microbiology
- Positive and Indeterminate COVID-19 final results will be reported to the appropriate Health Unit by PaLM Microbiology
Webform Users
- Hardcopy Reports will be delivered by fax, or established printer connections, to the referring hospital laboratory indicated on the COVID-19 requisition
- Positive and Indeterminate COVID-19 final results will be reported to the appropriate Health Unit by PaLM Microbiology
How to Interpret the Result
Interpretations include, DETECTED, NOT DETECTED, INDETERMINATE, AND UNABLE TO BE COMPLETED
Limitations of Interpretation:
- UNABLE TO BE COMPLETED: There is several reasons why testing cannot be completed. A quality assurance code will accompany each report and reasons can vary from leaked specimens to test failure due to interference substances present in the sample.
- INDETERMINATE: In a minority of tests, specimens with a weak-positive signal for the E-gene cannot be confirmed as positive by a confirmatory target. For inconclusive reports on patients where there is a strong suspicion of infection, another specimen should be tested no sooner than 24 hours later.
- NOT DETECTED: For negative reports on a patient with high index of suspicion for COVID-19 infection, additional specimens, including those from the lower respiratory tract, should be collected and tested. Factors that can lead to a negative result in an infected individual include:
- Poor quality of the specimen, containing little patient material
- Specimen collected late or very early in the infection
- Specimen not handled and shipped appropriately
PaLM Microbiology Assay Characteristics
- There was no cross-reactivity observed with other respiratory pathogens, including Influenza, RSV, and seasonal Coronaviruses. In other words, other respiratory pathogens do not cause false positive COVID-19 PCR results.
- To date, the analytical performance of 12 swab collection devices and a mix of nasopharyngeal, nasal, and throat specimens has been validated with the molecular assay. The clinical performance of these various specimen collection devices is not known due to the absence of a gold standard to confirm a positive case.
- False negative samples are infrequent but do occur and would appear to result from insufficient sample collection. A negative result does not rule out the possibility of infection, particularly for cases with a high probability of COVID-19 disease.
- Clinical judgement and multiple lines of evidence, including symptoms, medical imaging results, and contact with confirmed cases should be considered when making decisions for patient care and staff protection.
- This is especially important for the interpretation of indeterminate results were a weak signal is observed.