COVID-19 Probable Cases

Note: On 2/16/22, 17,467 cases based on at-home positive test results were excluded from the probable case counts. Per national case classification guidelines, cases based on at-home positive results are now classified as “suspect” cases. The majority of these cases were identified between November 2021 and February 2022.

CDPH tracks both probable and confirmed cases of COVID-19 to better understand how the virus is impacting our communities. Probable cases are defined as individuals with a positive antigen test that detects the presence of viral antigens. Antigen testing is useful when rapid results are needed, or in settings where laboratory resources may be limited. Confirmed cases are defined as individuals with a positive molecular test, which tests for viral genetic material, such as a PCR or polymerase chain reaction test. Results from both types of tests are reported to CDPH.

Due to the expanded use of antigen testing, surveillance of probable cases is increasingly important. The proportion of probable cases among the total cases in California has increased. To provide a more complete picture of trends in case volume, it is now more important to provide probable case data in addition to confirmed case data. The Centers for Disease Control and Prevention (CDC) has begun publishing probable case data for states.

Testing data is updated weekly. Due to small numbers, the percentage of probable cases in the first two weeks of the month may change. Probable case data from San Diego County is not included in the statewide table at this time.

For more information, please see https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/COVID-19/Probable-Cases.aspx

Data and Resources

Field Value
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identifier dc9f4603-12ee-482b-9ea5-fe10a45dbe02
issued 2021-06-04T20:52:28.000075
modified 2022-06-17T17:03:22.769486
publisher California Department of Public Health
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isopen False
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license_title License not specified
maintainer COVID-19 Response Data, Informatics, Surveillance, Clinical and Outbreaks (DISCO) Team
maintainer_email opendata@cdph.ca.gov
metadata_created 2025-11-23T00:05:50.277746
metadata_modified 2025-11-23T00:05:50.277751
notes __Note:__ On 2/16/22, 17,467 cases based on at-home positive test results were excluded from the probable case counts. Per national case classification guidelines, cases based on at-home positive results are now classified as “suspect” cases. The majority of these cases were identified between November 2021 and February 2022. CDPH tracks both probable and confirmed cases of COVID-19 to better understand how the virus is impacting our communities. Probable cases are defined as individuals with a positive antigen test that detects the presence of viral antigens. Antigen testing is useful when rapid results are needed, or in settings where laboratory resources may be limited. Confirmed cases are defined as individuals with a positive molecular test, which tests for viral genetic material, such as a PCR or polymerase chain reaction test. Results from both types of tests are reported to CDPH. Due to the expanded use of antigen testing, surveillance of probable cases is increasingly important. The proportion of probable cases among the total cases in California has increased. To provide a more complete picture of trends in case volume, it is now more important to provide probable case data in addition to confirmed case data. The Centers for Disease Control and Prevention (CDC) has begun publishing probable case data for states. Testing data is updated weekly. Due to small numbers, the percentage of probable cases in the first two weeks of the month may change. Probable case data from San Diego County is not included in the statewide table at this time. For more information, please see https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/COVID-19/Probable-Cases.aspx
num_resources 3
num_tags 13
title COVID-19 Probable Cases