The 10 Most Concerned Questions About Covid-19 Antibody Testing!

Link to register for COVID-19 antibody testing service at Diag Laboratories Here


Just because the entire population has been vaccinated does not mean that COVID-19 has completely disappeared. A subjectivity can also bring the pandemic back into the community. Let's join hands to implement "Antibody Testing, Next Step in the Fight against COVID-19" so that living with the virus is no longer a worry.

1. What Is Antibody Test?

“Detecting past cases of the virus by looking for antibodies that the patient has produced will be one of the most important goals in the fight against the COVID-19 pandemic. Antibody tests have multiple purposes: these serological tests are important for determining disease prevalence based on blood tests, prior exposure, and identification of people with high antibody levels. in serum to serve to collect serum samples from people who have recovered for treatment. Serology will assist in tracing the infection and screening healthcare workers to determine who is already immune.

How many people are actually infected, how many are infected but PCR is negative, and for what reason, how many patients are asymptomatic and the true mortality rate in a population What is the definite number? Only with comprehensive serological testing (and well-planned epidemiological studies) can we answer these questions and reduce the unknowns in current predictive calculations. Many investigations are underway in various locations around the world.”

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What is an antibody test (also known as an antibody test) is an indirect virus detection through the determination of antibodies in the blood. Antibodies are special proteins (IgM, IgG) that the body produces to fight infections.

2. Purpose of Antibody Test

In short, what is the purpose of a blood test for COVID antibodies?

What is the purpose of a blood test for COVID antibodies?

People who have been infected with Covid-19 and people who have received the Covid-19 vaccine will produce antibodies to prevent the disease. However, to detect whether the body really produces antibodies against the Sars-CoV-2 virus and whether the body has achieved immunity to this virus, it should be assessed through an antibody test.

  • Evaluation/monitoring of post-infection/postvaccination COVID antibody levels
  • Determination of humoral immune response to vaccines
  • Perform contact tracing for family or group, find out if the body has ever been infected with the virus
  • Assess the possibility of donating plasma

3. Who Should Perform Antibody Testing?

Who should perform an antibody test?

For Those Who Have Not Been Diagnosed With Covid-19

When you are infected with the virus that causes Covid-19, you may or may not have symptoms, and after a while, your body will make antibodies against the virus. You have never been diagnosed with Covid-19 and want to know if you have been exposed to the virus before?

The COVID antibody test provides a numerical value that indicates whether you have been previously infected and if Covid-19 antibodies are present in your body and determine your current immunity.

For Those Who Have Been Infected With Covid 19

About 1 week after infection with the SARS-CoV-2 virus, patients can recover because the immune system has created effective antibodies to fight the virus. Information about the antibodies produced will be stored, so that the next time, if this virus invades, the body can immediately have a weapon against it without having to wait long.

Testing for coronavirus antibodies to find a suitable and effective treatment solution with the serum of people who have recovered from infection.

For Those Who Have Been Vaccinated Against Covid-19

The COVID antibody test results play an important role in determining the level of antibody status after vaccination, assessing whether the injector's body is immune to the virus. The purpose of the COVID antibody test is to assist in the assessment of the body's immune response to the protein to SARS-CoV-2.

4. How Much Covid Antibodies Is Enough?

Antibodies form quite soon after the patient has been exposed to the SARS-CoV-2 virus and they are detected in the blood about 2 weeks later, antibodies gradually increase and persist for a long time in the body to store and against the virus for subsequent infections.

However, over time, the stored antibodies will degrade according to each subject's condition. For example, in young people with good health, the quantification of stored antibodies will have a longer time in the body to help increase the ability to fight the COVID-19 virus.

In the case of people with a weak immune system such as cancer patients during treatment, people using immunosuppressive drugs, the elderly, etc., the protective ability of antibodies is easily reduced.

So how much COVID-19 antibodies is enough? People who have never been infected with the SARS-CoV-2 virus do not produce antibodies. Therefore, the antibody quantitative test will be negative. For people who have been exposed to the SARS-CoV-2 virus and have been vaccinated with the COVID-19 vaccine, antibody quantification is determined based on a high or low antibody index, eg 100 U/mL.

Test results for antibody levels are divided into two categories.

  • Positive (≥ 50 AU/mL): Immune response to SARS-CoV-2. virus
  • Negative (< 50 AU/mL): No immune response to SARS-CoV-2. virus

How much COVID antibody index is enough? At present, it is not possible to determine how much COVID-19 antibody concentration is enough in the body. In addition to the antibody quantification results, the diagnostic doctor to make a conclusion is also based on other factors such as the person's medical history, liver, kidney, lung, cardiovascular, weight, etc.

Thus, the COVID antibody test helps to reflect a part of the body's immunity, and the exact results that indicate that the COVID antibody index is enough are no longer based on the totality of the factors of that patient.

5. How Much Does Covid Antibody Test Cost?

How much does a Covid antibody test cost?

How much does a covid antibody test cost? The cost of performing a blood test for COVID antibodies may vary depending on the services at medical facilities including testing equipment, origin, manufacturer, etc. Therefore, antibody testing is expensive. How much will not be the same in the base? Before deciding to register for an antibody test, should we consult the services that are included in the package, or are there any additional costs?

At Diag Laboratories, we perform antibody tests by analysis on Abbott – Alinity automated chemiluminescence immunoassay (CMIA) with a sensitivity of over 90% and a cost of 300,000 VND/person (not including the cost of sampling at home). Test results will be returned 2 hours after completing the sample collection.

6. When Should Antibody Tests Be Performed?

COVID antibody testing after vaccination or when is appropriate? According to experts, the appropriate time to perform antibody tests for each subject and time is as follows:

  • For people who have received the first dose of COVID-19 vaccine: 28 days after vaccination.
  • For people who have received the 2nd dose of the COVID-19 vaccine: the time is 14 to 28 days after vaccination.
  • For people after being infected with the SARS-CoV-2 virus: the time is 7 to 15 days after infection.

7. Where is the COVID Antibody Test?

According to the survey, we found that "Where is the COVID antibody test in Ho Chi Minh City?", "Covid antibody test at the market hospital", Hoa Hao COVID antibody test", "COVID Bien Hoa antibody test”, “Home COVID antibody test” are the keywords that people are most interested in.

Up to now, antibody testing has not been performed on a large scale, mainly in some central hospitals designated to test patients who have been infected with or are being treated for COVID-19 before being discharged.

Currently, we have deployed a COVID antibody testing service in Ho Chi Minh City and neighboring provinces under the branch of Diag Laboratories, we can provide COVID testing in Bien Hoa for customers who need it. Customers register for testing by filling out the registration form below:

Our support department will call you back to confirm the information and guide the nearest branch for the customer to come to collect samples according to the scheduled time frame.

At the same time, customers can also choose from one of our services such as home COVID antibody testing, home PCR testing, and general health testing services.

8. Covid-19 Antibody Test Method

The mean sensitivity and specificity of the FDA-approved antibody tests were 84.9% and 98.6%, respectively. At Diag Laboratories, we perform antibody tests using Abbott's automated chemiluminescence immunoassay (CMIA) analysis method – Alinity.


  • The positive prognostic value (PPV) is 92.92%
  • The negative prognostic value (NPV) is 99.97%

9. Covid-19 Antibody Test Result

How long does it take to return antibody test results? The time to return results at Diag Laboratories is 2 hours after receiving the sample.

  • Positive (≥ 50 AU/mL)
  • Negative (< 50 AU/mL)

Positive (≥ 50 AU/mL)

Âm tính (< 50 AU/mL)

Have ever been infected with the SARS-CoV-2 Virus

Have an immune response after vaccination

Never been infected with the SARS-CoV-2 virus

No immune response after vaccination against Covid-19

10. Antibody Antibody Test Procedure

The process of performing a Covid antibody test consists of 4 steps
  1. The medical staff takes a blood sample from the customer and sends it to the Diag laboratory.
  2. Analysis on an automated chemiluminescence immunoassay (CMIA) Abbott – Alinity i
  3. Diag notifies customers of antibody test results (online or hard copy)
  4. Customers receive detailed advice and instructions from our specialist doctors.

Register for COVID-19 antibody testing service at Diag Laboratories Here or click on the link below:

Click Here to view the nearest branch of  Diag Laboratories (Diag Medical Diagnostic and Testing Center).