A COVID-19 Home Test May Show False. Eight mistakes that will distort the result

Even 200-300 thousand. infections daily – so many cases of COVID-19 may be present in Poland. This is the opinion of experts. According to official statistics, there are about 30 infections. The reason for this colossal difference lies primarily in testing. Poles choose it on their own and willingly reach for home tests for the presence of coronavirus. When doing them, however, it is worth remembering that the result may turn out to be a false positive or a false negative. The reliability of the test may be increased by proper performance of the test. Check 8 errors that could make the result false

1. Home antigen tests are more and more often chosen form of COVID-19 diagnosis in Poland
2. However, such a quick coronavirus test can produce a false negative or a false positive
3. In order to avoid this, it is necessary to properly prepare for the test and perform it properly
4. The most common errors that can falsify the result of an antigen test include: cleaning the nose before the examination and incorrect swab collection from the nasopharynx or oral cavity. What else?
5. Check your health. Just answer these questions
6. You can find more about the coronavirus on the TvoiLokony home page

1. Too early or too late test execution

The antigen test, like the PCR test, should be performed at a strictly defined time. This is usually the period between the third and seventh day after a potential infection (exposure to SARS-CoV-2 virus) or the onset of COVID-19 symptoms. The fifth day was most often recommended. In the case of Omikron, however, this time has been shortened because the symptoms of infection with the new variant appear faster, even a day after contact with the coronavirus, usually about three days. Therefore, at present, the antigen test is best performed around the third day after the onset of COVID-19 symptoms or contact with an infected person (in the absence of symptoms).

At the beginning of the COVID-19 pandemic, it was said to be five to seven days from contact, for the Delta variant it was four to five days, and for the Omikron variant, it was said to be an average of three days from potential exposure to the virus. We can, of course, perform such a test after a day of contact, but we must take into account that a negative result will not give us certainty and we will have to repeat the test. We should take into account that more than one antigen test will have to be performed. It appears that on average, after three days of contact, we already have enough copies of the virus that the antigen test will be positive. More specifically, in the context of the Omikron variant, two or four days from the contact are referred to. The safest – and this is what global recommendations say – is to perform the test on the fifth day after contact, if previous tests gave a negative result and there is a suspicion that we may be infected

– confirmed in an interview with Medonet, MD. Bartosz Fiałek, rheumatologist and promoter of medical knowledge about COVID-19.

If the test is performed too early or too late, it may give a false negative result. In a situation where the test is negative, despite the fact that we experience symptoms characteristic of SARS-CoV-2 infection, it is worth performing a PCR test to confirm or rule out COVID-19.

1. See also: Home testing for COVID-19. What are their types and how to make them?

2. Consumption of a meal or drink before the test

Food or drink is not recommended before testing for coronavirus (both antigenic and PCR). How long before? Two hours minimum. Eating or drinking before taking the smear may falsify the test result. Smokers should refrain from lighting a cigarette during this time.

3. Failure to clean the nose prior to the examination

This is one of the most common mistakes made when performing rapid antigen tests at home. We think that cleansing the nose will make us blow the virus into the tissue, or rather the discharge (runny nose, which is a very common symptom of Omicron), in which it is located, and the test will turn out to be negative, despite the fact that we are infected with the coronavirus.

Meanwhile, it is just the opposite. In the nasal vestibule, there are often various pollutants that we breathe in with the air (for example dust and mites) and that can falsify the test result. That’s why it’s so important to blow your nose a few times before testing.

1. Check: These are the first symptoms of Omikron infection [LIST]

4. Use of nasal spray / drops

Like eating a meal or drink before the test, too the use of a nasal spray or drops may affect the result of the antigen test (and PCR). It is difficult to refrain from reaching for the medicine when you have a runny nose, but it is very important. There is more secretion in the unobstructed nose that is needed for the smear. In addition, the sample will not contain (or will contain a small amount if the drug has been used before) substances that are contained in the drug product.

1. See also: What should COVID-19 treatment at home look like? The most important recommendations of the expert

The rest of the text is below the video.

5. Use of an expired or damaged test

The offer of COVID-19 antigen tests on the market is growing. When choosing a product, it is important that it is appropriately sensitive and specific. – Antigen tests for the presence of SARS-CoV-2 infection must be at least 80 percent. sensitivity and 97 percent. specificity so that they can be introduced to the general market. Such guidelines were presented by the World Health Organization – explained the drug. Bartosz Fiałek.

It is also important to do not use the test after the expiry date or one that is damaged (dented packaging, torn foil / bags in which the kit components are located). An expired or damaged test can significantly lose quality and distort the result.

6. Contamination of test items

This is the last issue that may lead to a false antigen test result regarding the preparation stage of the test. A very important step is to wash your hands before opening the test package and its individual components. It is especially important to remove a stick from the protective foil used to collect a nasopharyngeal swab or a test tube for saliva collection, if you use the so-called lollipop test.

It is equally important to protect the plate on which we apply the sample and from which we read the result from contamination. If “foreign” contaminants enter these components, the test may “fail”.

7. Abnormal sampling (sample)

This is the most important step in performing an antigen test. The most trouble is when taking a nasopharyngeal swab, because the stick should be inserted quite deeply, which is not very comfortable. Too shallow use of the swab may prevent us from getting enough secretions that potentially contain viral particles, and the result will be unreliable. In turn, too deep insertion of the stick, although it will increase the chance of a reliable result, may harm us and damage the delicate tissues of the nasopharynx. In the correct application of the stick, it may be helpful to assume the appropriate position, by tilting the head slightly back.

1. End of nasty nasal swabs? There is a more effective test for the presence of Omicron

As for the saliva sample, the matter is simpler here. However, it should be remembered that the amount of saliva is sufficient to perform the test. The minimum level for the liquid is marked on the extraction tube to which the swab is taken. While it seems to be easy to obtain, it can be a challenge for children who are not yet able to spit saliva profusely. The more you should then take care to achieve the set minimum, and preferably a bit more.

8. “Missing” the time allotted for the interpretation of the result

Each test has a precisely defined time to mark the result. Usually it is about 20 minutes. from applying the sample to the plate (from 15 minutes to 30 minutes). It is not advisable to interpret the result both before and after this time.

In many cases, if the result is positive, the so-called two dashes (or one marked “positive”) appear fairly quickly, even after a few minutes, but this is not always the case. A reliable result may also appear after 15 or 20 minutes. Therefore, you should follow the instructions contained in the product leaflet and wait exactly as much as suggested by its manufacturer.

1. Also read: I am testing positive for coronavirus – what next? [WE EXPLAIN]

At the same time, we encourage you to listen to the latest episode of the RESET podcast. This time we talked about supplementation. What is its phenomenon? How to use it to help yourself and not to harm? What is worth paying attention to in supplementation with thyroid problems? Why you need to be careful with biotin? You will hear about this and many other things below.

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