Surveillance case definitions are intended for public health surveillance and reporting purposes and may not apply to clinical practice. 

Case definitions

Confirmed case

A person with confirmation of infection with SARS-CoV-2 documented by:

• The detection of at least one specific gene target by a validated laboratory-based nucleic acid amplification test (NAAT) assay (e.g. real-time PCR or nucleic acid sequencing) performed at a community, hospital, or reference laboratory (the National Microbiology Laboratory or a provincial public health laboratory) 

• The detection of at least one specific gene target by a validated point-of-care (POC) nucleic acid amplification test (NAAT) that has been deemed acceptable to provide a final result (i.e. does not require confirmatory testing)

• Seroconversion or diagnostic rise (at least four-fold or greater from baseline) ^a in viral specific antibody titre in serum or plasma using a validated laboratory-based serological assay for SARS-CoV-2
  

Probable - lab case

A person who:

1.

•  Has symptoms ^b compatible with COVID-19

• Had a high-risk exposure with a confirmed COVID-19 case (i.e. close contact) OR was exposed to a known cluster or outbreak of COVID-19

AND

• Has had a laboratory-based NAAT assay for SARS-CoV-2 and the result is inconclusive

OR

• Had SARS-CoV-2 antibodies detected in a single serum, plasma, or whole blood sample using a validated laboratory-based serological assay for SARS-CoV-2 collected within 4 weeks of symptom onset

OR

2. Had a POC NAAT or POC antigen test for SARS-CoV-2 completed and the result is preliminary (presumptive) positive ^c

OR

3. Had a validated POC antigen test for SARS-CoV-2 completed and the result is positive 

Probable - epi-linked case

A person who:

• Has symptoms ^b compatible with COVID-19

• Had a high-risk exposure with a confirmed ^d COVID-19 case (i.e. close contact) OR was exposed to a known cluster or outbreak of COVID-19

 AND

• Has not had a laboratory-based NAAT assay for SARS-CoV-2 completed ^e
  
  

  Notes
  

a.       A diagnostic rise in antibody titre can be established using paired acute and convalescent sera taken 2-4 weeks apart and tested using by an end-point enzyme immunoassay (EIA), quantitative EIA, or neutralizing antibody titres (e.g., plaque reduction neutralization (PRN)).

Note: At this time, serology testing should not be used for classification of cases who have been previously diagnosed with COVID-19, who have received a SARS-CoV-2 vaccination, for screening, or the routine diagnosis of acute infection.

b.       Symptoms compatible with COVID-19 include any 1 or more of the following:

• Fever or chills
•  Cough
• Loss of sense of smell or taste
• Difficulty breathing
• Sore throat
• Loss of appetite
• Extreme fatigue or tiredness
• Headache
• Body aches
• Nausea or vomiting
• Diarrhea 

1. A positive POC result should be considered as preliminary (presumptive) positive when reporting occurs prior to completion of POC validation or testing occurs in a non-licenced setting.
2. Cases who had a high-risk exposure with a probable COVID-19 case that had a positive result to validated POC antigen test for SARS-CoV-2 where confirmatory testing was not required (as per the provincial guidelines for POC test in Rural, Remote and Indigenous Communities) should also be considered probable – epi-linked.
3. For negative results from a compromised sample or if NAAT testing is delayed (e.g. >10-14 days following symptom onset), such persons remain as Probable - epi-linked.
   

For more information on laboratory tests, please refer to the Laboratory Comments available within the Public Health Agency of Canada's COVID-19 case definition document.