Health department adds rapid antigen tests to Covid-19 stats

The Department of Health has added the rapid antigen tests to the line of Covid-19 statistics, with immediate effect.

As a rule, testing for SARS-Co-V-2 in South Africa is based on the gold standard of a laboratory-confirmed polymerase chain reaction (PCR) test.

Initially, all Covid-19 positive cases were diagnosed through this method.

But earlier this month, the department identified approximately 75,000 antigen tests that needed to be captured into the database; of these tests, about 20,813 were diagnosed as positive for SARS-CoV-2.

It is important to note that the retrospective incorporation of these positive cases into the surveillance data will not impact case management and follow-up as the patient is immediately informed of a positive test result.

Rapid antigen tests gain popularity

In October 2020, rapid antigen tests were approved for use by the South African Health Products Regulatory Authority (Sahpra) and had been increasingly used by healthcare professionals to diagnose Covid-19.

These rapid antigen tests have been offered across the country in both the private and public sectors and through the mobile laboratories of the National Health Laboratory Service (NHLS) across the country. 

These tests provide easier access when it comes to diagnosing Covid-19 and provide results within 15-20 minutes of testing. 

Multiple manufacturers are now producing these tests and are using them for testing in line with Sahpra’s approval.

The country’s Covid-19 surveillance data is premised on capturing laboratory-confirmed case data of both the PCR and rapid Covid-19 antigen tests.

“Through ongoing efforts to ensure the best available surveillance data for decision-making, we are aware of several Covid-19 antigen tests from various sources that have not been incorporated into the laboratory information system,” said the health department.

Identifying this additional data is not unusual as data cleaning, quality checks and endeavours for completeness are ongoing processes.

“There have been extensive engagements with the National Incident Management Team, the provinces, the NHLS and the NICD [National Institute For Communicable Diseases Of South Africa], and we have included these data on 22 November so that it would reflect on today’s report,” said the department.

“As we report test data and case numbers for the past 24 hours through our outbreak reporting system, we will observe an increase in a single day, which will create a distortion of the seven-day moving average and an unusual spike on the reporting epidemic curve.”

Compiled by Narissa Subramoney