Coronavirus test (rapid test), molecular tests (PCR) & self-test

10+1 frequently asked questions about covid tests that you should know

1. Which coronavirus tests are there today to detect the SARS-CoV-2 virus?

There are 3 main tests to detect the virus in the body:

  1. Detection of the virus by a molecular method (PCR)
  2. Detection of specific antibodies against the coronavirus by a classical serological method
  3. Rapid diagnostic tests for coronavirus (Covid Rapid Tests), can detect the virus or the specific antibodies against the virus.


2. What is and how is the molecular method for the detection of coronavirus (PCR) performed?

The SARS-CoV-2 molecular detection method detects the genetic material of the virus using the laboratory PCR technique. It very accurately determines if someone is infected with the coronavirus now whether they are asymptomatic or not.

It is performed with a nasopharyngeal or oropharyngeal smear with a special flexible swab by specialized health personnel. SARS-CoV-2 RNA test results are usually available within 24 hours.

3.  How can we find out if we have antibodies for the SARS-CoV-2 coronavirus?

It is possible to conduct a rapid test for coronavirus antibodies (Rapid test IgM/IgG) to detect SARS-CoV-2 antibodies in the body. The Anti-SARS-CoV-2 assay is an immunoassay for the qualitative detection of IgM/IgG antibodies in human serum and plasma.

The presence of coronavirus antibodies in the body indicates recent exposure to the virus. Through a drop of blood, the rapid coronavirus test can detect antibodies the virus causes in the body, which could signal whether a person has already been infected and possibly developed immunity to the virus.

It is performed by health personnel or by the examinee himself as a very small amount of blood is required. The results of the Anti-SARS-CoV-2 coronavirus rapid test are available within 15 minutes.


4. What are serological tests and the IgM, IgG, and IgA antibodies they detect?

With serological tests, we check whether there are antibodies against the coronavirus in a person’s blood. According to the World Health Organization, serological tests are considered auxiliary and not main tests for the diagnosis of the coronavirus.

The main antibodies produced by the human body against microbes are of two types: IgG and IgM. IgM antibodies are produced in the first days after the onset of symptoms and usually remain in the body for 1-2 months. IgG antibodies appear in the blood a little later than IgM and usually remain in the body for several years.

IgM antibodies are what provide the first line of defense during viral infections and IgG antibodies are the adaptive immune response. Both are very important for the development of long-term immunity.

5. How many types of rapid tests (rapid test SARS-CoV-2) are there?

There are rapid coronavirus antigen tests that use a small amount of saliva, stool, or nasopharyngeal swab samples such as the reliable and certified rapid antigen test COVID-19 CORONA-Ag and rapid coronavirus tests that use only a nasopharyngeal or oropharyngeal swab sample such as the SARS antigen Rapid Test -CoV-2 COVID-19 DyonCovidAg. In addition, for cases where the presence of SARS-CoV-2 antibodies in the human body is examined, there are VivaDiag SARS-CoV-2 IgM/IgG Antibody Rapid tests which use a blood sample (1 drop).

6. How reliable are rapid coronavirus tests?

Rapid coronavirus tests have been shown to be more reliable (in the order of 95%-100%) compared to PCR molecular tests (which are performed in microbiology centers) in cases of high viral load. But as the viral load decreases, the sensitivity is lost and decreases to a level of up to 76%. This results in the loss of positive samples.

Ideally, when the viral load is not high, molecular PCR testing is also recommended).

7. In which cases is the detection of specific antibodies against the SARS-CoV-2 virus used?

The detection of specific antibodies against the SARS-CoV-2 virus using a rapid coronavirus antibody test or a molecular antibody test is indicated in cases where it is necessary to establish whether someone has “passed” the infection in the recent past, even if they had mild or and no symptoms.

8. Can I do a self-test for coronavirus at home (Self-test)?

A citizen can obtain a self-test for the SARS-CoV-2 coronavirus and without the help of an expert, he can do it alone at home (self-test). Thus, within 15 minutes to know whether he is positive or not for the coronavirus COVID-19. Detailed instructions for use are included in each test, they are available in a package of 6 pieces or 1 piece and you can get them from or from pharmacies with your AMKA and your ID. Positive or negative results will be declared on the new government platform here.

9. What is the difference between self-tests and rapid coronavirus tests?

The coronavirus self-tests belong to the category of rapid coronavirus tests but with an easier sample collection process and are packaged in separate packages. Supervision by a health professional is not required (as in rapid coronavirus tests) as they work with a saliva sample or a nasal sample (Covid nasal self-test) and not a nasopharyngeal or oropharyngeal one.

10. Is the rapid test, which is performed only with a saliva sample, reliable?

The research and studies that have been done on the rapid test of coronavirus antigens COVID-19 CORONA-Ag prove that the rapid tests of coronavirus that are done with a saliva sample can be as reliable as the rest of the coronavirus tests that are in circulation. They are more economical and simpler to perform, not intrusive at all, and with less risk of contamination. They are ideal for children and people who are uncomfortable taking a sample from the nasopharyngeal cavity.

In detail, the coincidence rate of the rapid test for the antigens of the coronavirus COVID-19 CORONA-Ag and the PCR test in nasopharyngeal and pharyngeal swab samples:

– In pharyngeal saliva – pharyngeal swab samples:
Positive case rate (sensitivity) = 90%, (95% Cl 79~96.24)
Adverse event rate (specificity) = 100%. (95% Cl 88.43~100)

–In sputum samples:
Positive rate (sensitivity) = 95%, (95% Cl 86.08~98.96)
Adverse event rate (specificity) = 100%. (95% Cl 88.43~100)

–In stool samples:
Positive rate (sensitivity) = 95%, (95% Cl 86.08~98.96)
Adverse event rate (specificity) = 100%. (95% Cl 88.43~100)

10+1. Does the coronavirus test hurt?

The tests that are done to detect the coronavirus, whether they are molecular (PCR) or rapid tests (covid rapid tests), cause little to no pain. The nasopharyngeal swab COVID-19 tests cause a slight discomfort/tickling which goes away within half an hour after the sample is taken. The coronavirus antibody test done with a blood sample only causes a momentary prick to drip a drop of blood onto the sample surface. The pain caused is momentary and under no circumstances should it hurt later.

Sources: GovGR, EODY, MyLab, Euroclinic, Capital, Metropolitan hospital, ProtoThema

1 Comment

  • Καρδιολόγος

    Τα θετικά αποτελέσματα του rapid test είναι συνήθως εξαιρετικά ακριβή, αλλά τα αρνητικά αποτελέσματα μπορεί να χρειαστεί να επιβεβαιωθούν με ένα τεστ PCR. Τα rapid tests είναι πιο αποτελεσματικά μία έως πέντε ημέρες μετά την έναρξη των συμπτωμάτων.

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