COVID-Schnelltest

There are different ways to prove that someone has been infected with the coronavirus. Currently, three methods are predominantly used. However, researchers are already working on new procedures in laboratories which should enable faster results or easier delivery. AT&S printed circuit boards play an important role in these processes.

The two methods mainly used at present to identify acute COVID infections are PCR tests and antigen tests. Both methods mostly use an oropharyngeal swab on the persons to be tested. A PCR test (PCR stands for polymerase chain reaction) identifies the genetic material of the coronavirus directly in the sample. To do so, qualified staff has to take the sample, which is then processed and analyzed in the lab. The antigen test identifies proteins of the coronavirus in the sample. This goes fast, but the test is less sensitive than a PCR test.

The third common method, the antibody test, is not suitable to identify an acute infection because it may take up to three weeks for antibodies to form in the body of infected persons. Antibody tests are used to determine the percentage of people previously infected in a population.

Disadvantages

PCR tests are highly sensitive and deliver accurate results. However, it usually takes at least 24 hours. This is because the RNA of the coronavirus has to be extracted from the sample in the laboratory and then transcribed into DNA and multiplied until the detection threshold is reached. By now there are also rapid PCR tests which perform these steps in integrated minilabs and deliver a result after roughly two hours. However, these rapid tests are less reliable and significantly more expensive than PCR tests carried out in the laboratory.

The disadvantage of antigen tests is that they often produce false negative results. Persons who are tested positive are infected, but if the result is negative, there is a possibility that the person tested might be infected after all. The only way to provide clarity is an additional PCR test. However, it only takes about 30 minutes to get a result from an antigen test.

Rapid tests work because today complex lab technology can be built into a housing that is not much larger than a smartphone. Miniaturized printed circuit boards made by AT&S are of central importance in many minilabs. A newly developed antigen rapid test device that includes AT&S technology is expected to deliver results after only 12 minutes in the future.

New tests

Since all methods currently known involve disadvantages, researchers across the globe continue to work on the development of new corona tests. The focus of attention is often on minilabs in this area as well: Researchers in Belgium for example are working on performing PCR tests with breath specimens on silicon chips. The persons tested would then only have to breathe into a container and would receive a result five minutes later.

The EU-funded research project CORONADX is taking a different path. A novel test called PATHAG will provide a reliable test result within 60 seconds and does not require trained personnel or a laboratory. Corona antibodies are embedded in microscopic latex beads and then mixed into the sample to be tested. If the virus is present in the sample, the antibodies bind to the virus’s particles, carrying the latex beads with them to form a clump that can be seen with the naked eye.