COVID-19 testing, the process behind the result

9th June 2020

As of June 8th, 920 064 COVID-19 tests have been conducted with 48 285 of them returning positive results.

Random testing and the scarcity of resources have made it difficult for testing facilities to keep up with result demands.

A process that typically takes 3 to 5 days has been extended to weeks and in extreme cases like in the Eastern Cape, a full month due to the sheer amount of tests the few in number facilities need to process.

The entire process itself consists of coordination between health professionals and facilities taking into account various factors.

According to the National Institute for Communicable Diseases, the current case definition for persons under investigation who should be tested for COVID-19 is as follows:

The patient presents with symptoms such as a cough, sore throat, shortness of breath, or a fever (>38°) AND in the 14 days before the onset of symptoms, met at least one of the following criteria:

  1. Was in close contact with a confirmed or probable case of SARS-Cov-2 infection; OR

  2. Has a history of travel to areas with local transmission of SARS-CoV2; OR

  3. Worked in or attended a healthcare facility where patients with SARS-CoV-2 infections were being treated; OR

4.Was admitted to hospital with severe pneumonia of unknown origin.

The testing procedure varies however the most commonly used method is attaining nasopharyngeal (through the nose) and oropharyngeal (from the back of the mouth) swabs which are then placed into a universal transport medium for same-day delivery to the testing facility.

Keeping at a 2°-8°C temperature during transport and storage to prevent sample decay, the samples undergo the actual testing process once they reach the laboratory.

Dr. Jean Maritz, a clinical virologist at PathCare explained to the Daily Maverick that the testing process is based on the amplification and detection of unique SARS-CoV-2 viral nucleic acid sequences by a real-time polymerase chain reaction machine, which essentially makes copies of the virus's genes if any are found in the sample.

This process takes about 2 hours generating a result.

Keeping track of each result is done by assigning details of the specimen, such as patient ID and the name of the referring doctor, and capturing the data onto a system.

The results are then printed and sent out by a medical scientist who prioritizes positive cases.

The pathologist is contacted first, who then contacts all the referring doctors to make sure that those patients are made aware that they have tested positive for COVID-19.

Dr. Maritz says: "At the moment we are sticking to the case definition for testing someone for Covid-19. If you display any symptoms, it is important to phone your doctor or the emergency room and ask them whether you can come for an assessment. We need this mechanism. We are inundated with tests, we have scarce resources and we need to rationalize the use of these resources and we rely on all healthcare workers to help us in maintaining our capability to test all of those that need testing."

Medical professionals all over the country have appealed to the government to stop random COVID-19 testing and to deal with the testing backlog.

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