The National Department of Health has confirmed that antibody testing is now legal in South Africa.

On Monday evening, Health Minister Zweli Mkhize announced: "Today I am pleased to announce that the director-general for health has issued guidelines for the use of SARS CoV 2 antibody tests and that Sahpra announced its approval of several test kits, both lab based and point of care or bedside rapid tests.

"I am sure this is a very welcome development and I would like to especially thank the Ministerial Advisory Committee on Covid-19 and the various members of the strategic management bodies in the Department of Health for all the hard work that has gone into ensuring that antibody tests are used appropriately and effectively as we continue to battle Covid-19. It will be important to understand the limitations of antibody testing."

The department's announcement follows a week of confusion in which antibody tests were first advertised by private laboratory companies, and then withdrawn days later, pending the release of a national algorithm.

But on Monday, the South African Health Products Regulatory Authority (Sahpra) updated its website and provided an updated "list of authorised serological test kits".

It included seven companies offering a "Serological Corona virus IgG/IgM Rapid", point-of-care test kit, by Zheijiang Orient Gene Biotech:

• Tip Top Trade (Pty) Ltd
• Link Medical Solutions (Pty) Ltd
• Direct Retail Goods (Pty) Ltd
• Nu-world Industries (Pty) Ltd
• Inqaba Health Solutions (Pty) Ltd
• Sinosa Trading (Pty) Ltd
• Doctor Four You Practice Managers (Pty) Ltd
• Also announced were three companies offering different "SARS CoV-2 ELISA IgG" laboratory-based serology tests:
• Roche Diagnostics (Pty) Ltd
• Abbott Laboratories South Africa (Pty) – with tests from its division in Ireland
• Euroimmun Medical Laboratory Diagnostics

Referring to the "rapid, point-of-care tests", Sahpra explained: "The difference between the molecular PCR test and the serology tests is that the PCR tests are able to detect and diagnose whether one has been infected with Covid-19 and thus give a clinical diagnosis."

Tests can't be conducted at home, must be validated

Commenting on the laboratory-based tests, it added: "Whilst the latter, ie serology tests, can detect if one has developed antibodies for Covid-19 or not. Serology tests cannot be used for clinical diagnosis. Serology tests cannot be conducted at home, they have to be administered by qualified healthcare professionals and must have been validated. These tests should only be used within the national Department of Health's surveillance strategy. Licence holders are required to report any product quality problems identified with their products in accordance with Regulation 40 of the Medicines and Related Substances Act, 1965 (Act 101 of 1965)."

Sahpra CEO Dr Boitumelo Semete-Makokotlela said: "Rapid test kits cannot be used to clinically diagnose Covid-19 cases, but they may play a role in research, epidemiological as well as sero-surveillance studies. Rapid test kits are not recommended by [the World Health Organisation] for clinical diagnosis of SARS-Cov-2 infection."

Sahpra said the regulatory requirements for rapid test kits were published on 30 March on its website and the specification criteria for serological test kits had been developed (MD007) and published on 20 April 2020.

The rapid test kits "may only be manufactured or imported by Sahpra-licensed medical device establishments once the test kits have been validated by an independent laboratory".

Limitations to test

In his announcement on Monday night, Mkhize said: "Use of SARS-CoV-2-specific IgG antibodies for epidemiological purposes, that is to identify and track the transmission of certain geographical areas or populations - this will be a particularly useful application that will complement our surveillance strategies."

But the minister also issued the following warnings about the antibody testing:

"Antibodies are usually detected more than 10 days after onset of symptoms or even only during convalescence (recovery).

"A negative antibody test result does not reliably rule out prior SARS-CoV-2 infection. For instance, someone may not generate the antibodies or high enough titres for antibodies to be detected.

"A positive antibody test result does not reliably prove prior SARS-CoV-2 infection. There is known cross-reactivity with other viruses and there may be antibodies already existing in someone's system that look like Covid-19 antibodies.

"The detection of antibodies does not necessarily mean one is immune," Mkhize insisted.