Nowadays, there is a wide range of C19 detection kits available on the market and it is difficult for people to choose the suitable one for their work in clinic or for testing at home. All tests for fast detection of antigens or antibodies against this virus are easy-to-use, at low cost and do not require any special equipment.
What types of samples should be collected for testing and how?
A tiny drop of blood collected by finger stick is needed to perform the test for detection of antibodies against the pathogen. Nasal sample collected with a nasopharyngeal swab is used for antigen testing. The sample collection procedures usually do not cause any pain but both should be done with a special care and attention when you need to test your children. When performing Accu-Tell Ab tests, put the whole blood/serum/plasma sample on S place of the cassette. Тhe buffer should go to the B place and this part of the cassette should stay clean without any drop of blood. In this case, the test can be interpreted as invalid.
What types of tests are available on the market?
The standard method for detection of new viral respiratory infection is the PCR assay. The results from this test define the customer as “positive” or negative” and are the reason for the local health authorities to take all precautions for the isolation of the positive individuals. PCR requires specific equipment and reagents so it is performed in a clinical or research laboratory only. Theoretically, antibody and antigen tests like Accu-Tell, Panbio and BioCredit can be done at home but medical assistance is required for accurate sample collection.
Gentaur/Genprice recommends you to consult with your doctor if you want to be tested C19 with rapid antibody and antigen rapid test kits.
PCR is the most accurate and reliable method for detection of C19 in the early days of the infection. Antigen test kits for fast results have high sensibility and specificity comparative with PCR. The results from these tests show the presence of active viral particles in the human body. The presence of IgM in the blood sample detected by antibody test kit shows that the patient has an active C19 infection. If there is a positive result for IgG, that means the patient has active or passed infection. If there are no symptoms, people positive for IgG and IgM has an immunity against the virus, cannot be infected within the next months and transmit the disease to other people.
How many tests are included in 1 box?
The test kits for fast detection of the new respiratory infection usually contains 20, 25 ,40 or 50 tests. The prices vary between 4 and 10 EUR per test. Along with the test cassettes/cards, the kits contain a bottle of a buffer in a volume enough for the performance of all tests from the box. Specialists recommend to use the first test cassette as a reference to check the quality of the kit. You can leave the sample place blank and add 2 drops of the buffer to see the change in the colour of the control (C) line. If the colour does not change in dark, the test is invalid or expired. The dark line should be visible enough under a lamp or day light so you do not need and special equipment or lights to check the results.
Do you have to be a doctor to do the test?
Only biologists and laboratory assistants have the knowledge and skills to perform PCR since it requires highly specific equipment and consumables and it should be done in a sterile laboratory. The antigen and antibody tests are easy-to-use and it can be done at home but the trick for the obtain of correct and reliable results is in the collection of samples – blood or nasal probe. Therefore, manufacturers announced that all kits are for professional use only.
The basic steps for Ag or IgG/IgM testing are:
- Collect a drop of blood with a finger stick or a nasal probe with a nasopharyngeal swab;
- Put the sample on S (sample) place on the cassette
- Add the buffer to the B (buffer) place on the cassette
- Wait for 5-10 minutes and then you can see the results
What is the difference between an antigen and an antibody test?
Antigen tests detect specific part of the viral particles in the samples and prove the presence of active infection even if there are no symptoms. Patients with positive results should be isolated and present information about the people they have been in contact with.
Antibody tests show the presence of both active or passed infection. If you are IgM positive, may you are still infected with C19 and can transmit the virus to other people. The presence of both IgM and IgG is a proof for active or passed infection and the patient has an immunity against the virus.
Antigens can be detected on day 3 up to day 30 after infection. IgM could be detected at day 5. Both antigen and antibody test results should be confirmed by PCR assay.
Should people that are IgG positive, symptom negative IgM negative, antigen negative and PCR negative still stay at home?
No, they shouldn’t. They could live their home and not wearing a mask. However, the instructions from the local health authorities should be followed strictly and all people should wear a mask. Patients with IgM negative and IgG positive can test themselves every 2 weeks and follow their antibody progress. The antibody test kits contains 25 tests and have a expiry date of 2 years.
What is the difference between a IgM or IgG positive result?
IgM is the immediate response of your immune system. The secretion of IgM antibodies starts around 4-5 days after the infection with COV2 virus. People with positive IgM results can transmit the infection.
IgG is the response after 10 or more days.
IgM positive means you are infectious
IgG positive means you have had an old infection and in absence of IgM, PCR or Antigen you are safe to yourself and others.
When am I safe having a negative test?
If you have been tested PCR negative after days after your last contact you are safe
If you are antigen negative after 5 days after your last contact you are safe
If you are IgM negative after 7 days after your contact you are safe that is why antigen tests are preferred to antibody IgM tests
If you are IgG negative 6 months after an old infection there are cases where people get this Sars a second time so the IgG is a parameter for protection being in that period safe to everyone in absence of PCR, antigen and IgM positive results.
Can I have only a positive IgG test?
Yes this means you survived well and old infection. If you have no permanent handicaps from your viral period this is very good news! You are free to travel, work and help everybody.
Doe it hurts to do a Covid test?
It hurts a little. The Schwab is a little uncomfortable especially for children and the blood sample hurts only 10 seconds. I prefer to test children with a blood sample but depending on the child and the schwab shape some people prefer schwabs.
Are there Flu and Corona tests that combine the 2 tests in 1 cassette?
Yes this is a very useful test since lots of people mix-up flue symptoms with corona symptoms. Tauns Capillia has a very useful combo flue cov test and they also have the best flue self test today available.
Are IgG tests better than antigen or PCR tests?
For new infections PCR is better than antigen is better than antibody IgM. IgG is actually never used to detect new infections, never. IgG is used to monitor your immune protection to an old at least 7 days od infection.
Are antigen tests better than antibody tests?
Yes and no. To know the danger antigen test are better and faster. Once you know you have it to test the danger of infection still someone after you have no symptoms anymore, IgG is the only test that can give you this information. Conclusion: antigen tests are better to detect the virus and IgG IgM tests are better to monitor the progress of the disease.
What test producing companies are available?
Panbio antigen Abbott, 25 tests a box, 185 Euro
BioCredit antigen test, 20 tests a box, 195 Euro
Lepu Medical antigen, 20 test a box 215 euro
Salience antigen test 25 tests /box 195 euro
healthbiotech COVID-19 antigen test kit 25 tests 175 euro
Accutell antibody IgM IgG 25 test a box for 165 euro
Lepu antibody 20 test a bor 185 euro
Is PCR the best test?
Yes because it detects as early as in 2, 3 days after infection the virus but due to a severe stock problem of filter tips and PCR reagents the PCR is not available for everybody in 2021 2022. It is also a very expensive technique with prices of 100 euro a test while rapid tests are only average sold at 5 euro a test.
PCR is slow, results come only after 3 hours the earliest or 2 days while in 60 seconds are home test can be performed by a non medical person.
Author: Lieven Gevaert, Bio engineer of the university of Gent 1996 Works with sars1 antibodies since 2003 as scientific advisor for Gentaur group in Europe
