How the COVID-19 self-test works – Health – Tecnoblog

The National Health Surveillance Agency (Anvisa) has already approved COVID-19 self-tests for sale in pharmacies. First of all, it is important to emphasize that the tests carried out by the individual serve only as a “screening” – the diagnosis must be made in a health unit. If you intend to do a prior check for suspected infection, understand how the COVID-19 self-test works and the different ways of collecting the product.

Understand how the Covid-19 self-test works (Image: Alexandra Koch/Pixabay)
Understand how the Covid-19 self-test works (Image: Alexandra Koch/Pixabay)

On the Anvisa page, it is possible to follow the complete list of tests, approved by the regulatory body, through an electronic panel that is periodically updated. The first product that received the endorsement was the Novel Coronavirus (Covid-19) Antigen Self-Test, from the company CPMH, developed for the use of a non-deep nasal swab sample (a type of “swab”). This method stands out among the goods with approval.

On the other hand, so far, there is only one self-test in the list that uses another form of collection, performed by means of a saliva sample: the COVID Ag Oral ECO Detect, from the company Eco Diagnóstica. Even with the different collection methods, both are self-tests for the detection of SARS-CoV-2 antigens. That is, they aim to identify the presence of virus components in the sample.

How does Novel Coronavirus (AT-Ag) work?

According to the manufacturer, when introducing the swab into the nasal cavity and, soon after, dipping it in the liquid contained in the plastic tube that comes in the kit, parts of the virus (when the microorganism is present) are transferred to this substance. Then, by dropping the liquid into the hole of the test card, a line forms in the T (test) region, which means that virus particles have been detected in the sample.

In addition, a line in the C (Control) region should always be formed — this is an indication that the test has proceeded properly. You must wait 15 to 30 minutes to read the result.

Heads up: In order to test correctly, it is very important to carefully follow the instructions for use. Also check out the step-by-step video.

How does COVID Ag Oral ECO Detect work?

In this test, the person must pull mucus from the back of the nose and throat and spit out the saliva mixed with the mucus into a cup — the container must not touch the mouth. The sterile swab must be used to collect the saliva from the cup and, soon after, immersed in the liquid contained in the plastic tube that comes in the kit.

The mixture from this container must be dripped onto the test card. From that point, a line forms in the T (test) region when virus particles are detected in the sample. In addition, a line in the C (Control) region should always be formed — this is an indication that the test has proceeded properly. You must wait 15 to 30 minutes to read the result.

Possible self-test results (Image: Publicity/Eco Diagnóstica)
Possible results of the Covid-19 self-test (Image: Disclosure/Eco Diagnóstica)

Heads up: To carry out the test correctly, it is essential to follow the instructions for use of the kit in detail. Check out more information in the product flyer and also in the step-by-step video.

What is a Covid-19 self-test?

According to Anvisa, the self-test must allow the person to do all the testing steps, from sample collection to result interpretation, without the help of a professional. Of course, the product must offer instructions for use in simple language and an illustrated step-by-step guide, in order to facilitate its understanding and execution.

What is the right period to do so?

According to the Ministry of Health, the self-test should be done between the first and seventh day of the onset of symptoms, or five days after contact with another person who has had a confirmed diagnosis of the disease.

When should Covid-19 self-tests not be used?

The test carried out by the individual himself is not valid for the purposes of sick leave from work, nor for the presentation of a negative result in international travel. It is worth remembering that it also does not serve to determine a diagnosis, as it is considered a form of screening.

With information from: Ministry of Health, Anvisa¹, Anvisa², CPMH¹, CPMH², Eco Diagnóstica¹ and Eco Diagnóstica².

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