COVID-19 Testing Over Time

Note: On 1/31/2023 we made the following changes:

• Renamed the column "last_updated_at" to "data_as_of"
  
• Added the following columns:
  
  • "cumulative_tests"
    
  • "cumulative_positive_tests"
    
  • "cumulative_negative_tests"
    
  • "cumulative_indeterminate_tests"

A. SUMMARY
Case information on COVID-19 Laboratory testing. This data includes a daily count of test results reported, and how many of those were positive, negative, and indeterminate. Reported tests include tests with a positive, negative or indeterminate result. Indeterminate results, which could not conclusively determine whether COVID-19 virus was present, are not included in the calculation of percent positive. Testing for the novel coronavirus is available through commercial, clinical, and hospital laboratories, as well as the SFDPH Public Health Laboratory.

Tests are de-duplicated by an individual and date. This means that if a person gets tested multiple times on different dates in the last 30 days, all of those individual tests will be included in this data as individual tests (on each specimen collection date).

Total positive test results is not equal to the total number of COVID-19 cases in San Francisco. Each positive test result is investigated. During this investigation, some test results are found to be for persons living outside of San Francisco and some are duplicates of previously received positive results. These are not included in the total San Francisco COVID-19 case count. Additionally, investigation of positive test results might not be completed on the day of receipt; new cases will be added to the total case count after full investigation and verification.

B. HOW THE DATASET IS CREATED
Laboratory test volume and positivity for COVID-19 is based on electronic laboratory test reports. Deduplication, quality assurance measures and other data verification processes maximize accuracy of laboratory test information.

C. UPDATE PROCESS
Updates automatically at 05:00 Pacific Time each day. Redundant runs are scheduled at 07:00 and 09:00 in case of pipeline failure.

D. HOW TO USE THIS DATASET
Due to the high degree of variation in the time needed to complete tests by different labs there is a delay in this reporting. On March 24 the Health Officer ordered all labs in the City to report complete COVID-19 testing information to the local and state health departments. In order to track trends over time, a data user can analyze this data by "result_date" and see how the count of reported results and positivity rate have changed over time.

E. CHANGE LOG

• 1/31/2023 - renamed column “last_updated_at” to “data_as_of”.
  
• 1/31/2023 - added columns “cumulative_tests”, “cumulative_positive_tests”, “cumulative_negative_tests”, “cumulative_indeterminate_tests”.
  
• 4/16/2021 - dataset updated to refresh with a five-day data lag.