Rapid virus testing is two weeks away

In two weeks, Kenyans might be able to do rapid testing to determine whether one has the coronavirus, if plans by a team of local scientists are anything to go by.

The tests will be designed like the rapid HIV diagnostic tests kits, which will be able to give results in three to 15 minutes. The aim is to test as many Kenyans as possible in a bid to curb the current coronavirus pandemic.

“Making rapid diagnostic test kits is not rocket science,” says Matilu Mwau, an infectious diseases professor and a deputy director for Diagnostic Laboratories at Kenya Medical Research Institute (Kemri).

Prof Mwau says the accuracy of the tests kits is the most important part of the process, being careful not to have a test kit that will be positive for other coronaviruses and not the SARS-CoV-2 that causes Covid-19.

Globally, the accuracy of the rapid diagnostic kits has been between 30 and 94 per cent in detecting the coronavirus.

“You have to understand the virus first through culture and growing it in the lab so that you are able to see its design and the antigens,” Mwau explains about the initial stage of designing a rapid test kit.

The other option Kemri is considering is replicating the test kits that are already in the market and producing them en masse for millions of Kenyans, especially those in the designated red zones.

Kemri says it has the materials and capacity of producing hundreds of thousands of test kits, per day, through its production unit stationed at its Nairobi headquarters.

Currently, the laboratories in Kenya are using manual PCR testing for the diagnosis of Covid-19, a process that takes anything from 45 minutes to three hours for the lab process to give a result. This turnaround time is exclusive of the logistics of obtaining the sample from the suspected patient and transporting it to the laboratory for processing.

Transporting the virus from the patient to the lab requires a special substance called the Virus Transport Media (VTM), which Kemri is also currently producing for the ongoing tests across the country and the other 18 countries that it supports, including Somalia.

“The Virus Transport Media is made with some raw materials which we import and process in two of our laboratories,” says Joel Lutomia, Kemri’s deputy director Centre for Virus Research.

The two labs have been routinely producing this transport media because they are labs involved in regular surveillance of infectious viruses for the last 20 years.

Each can produce 10 litres of the media daily. The 10 litres of transport media can process at least 3,000 samples. There was scarcity of the transport media for the number of suspected cases that were already in the country.

“We have been producing the media on a need basis, but if we need to scale up to meet demand or mass testing, we can produce up to 60 litres per day, which can process at least 18,000 samples a day,” Dr Lutomia says.

The media is produced in a clean laboratory where the laboratory scientist mixes all the raw materials in a clean biosafety cabinet. Afterwards, the end product is put in small sample bottles in which the tip of the swab used to collect the sample from a patient will eventually be put in.

The media contains, among other components, antibiotics and antifungals. These kill any other germ that is not a virus and sodium bicarbonate that stabilises the virus within its pH, long enough for it to get to the lab for the actual processing to detect the presence of the coronavirus.

The media has a lifespan of two weeks. Once a swab is taken, one has 72 hours within which to transport the sample in a cool box of 2-8 degrees Celsius, from the patient to the lab.

Should raw materials run out during the pandemic, the reference lab is working on contingency measures to have a cargo plane bring in the materials.

Samples done

Of the 4,227 samples done as of Monday, Kemri had processed half of the tests. Kenya expects to get test reagents for the digital processing of the samples by a PCR machine that can process up to 2,000 samples in 24 hours in each of the Kemri labs.

In addition, Mwau recommends that the 187 Gene X-Pert machines in several counties should be activated to process more tests across counties, despite the manual processing that it requires.

“These machines have been used for the molecular processing of TB and HIV and can process 20 samples in a day, and there will be no need to send samples across counties or to Nairobi,” he says.