Antibody test is a blood test to check if you’ve either had coronavirus before or developed antibodies after having the COVID-19 vaccine. — Photo medlatec.vn

HCM CITY — After recovering from COVID-19 a month ago, shipper Nguyễn Văn Út Em in HCM City’s Bình Tân District wanted to take an antibody test as he expected the result would help him get a “COVID-19 green card” – a requirement for him to resume work.

Thanks to a recommendation by his friend, the shipper arrived at a medical facility in the city to take the test - a blood test to check if you’ve either had coronavirus before or had antibodies after having the COVID-19 vaccine. An antibody test is different to the swab test to check if you have COVID-19.

The shipper said that in late July, after having a cough and fever for three days, he took a rapid antigen test at home. The test result showed that he was positive for SARS-CoV-2.

The man said that he was unable to contact local health workers, so he treated himself at home with medicines bought at a nearby pharmacy.

“All the symptoms disappeared after 14 days and I tested negative for the coronavirus,” Út Em said.

“I was told that an antibody test could prove I recovered from COVID-19. So, I will be eligible to get the COVID-19 green card issued by local authorities, allowing me to return to work,” he said.

Trần Thị Kim Cúc, a fully vaccinated woman in District 7, wanted an antibody test to verify if her body created antibodies after vaccination.

She thought that with existing antibodies, she would face fewer risks of COVID-19 infections as well as a better chance against the virus if she caught it.

Cúc spent VNĐ450,000 for the test at a local medical facility, she said.

Seeing increasing demand for antibody tests, medical facilities in the city started offering the service.

People who recovered from COVID-19 at least seven to 15 days ago or those who received a COVID-19 vaccine within 14-28 days can take the test.

If a sample is taken at the medical facilities, the service costs about VNĐ450,000 - VNĐ500,000 per person. If the sample is taken at home, users pay about VNĐ1.2 million – VNĐ1.3 million per test. Clients in groups will be offered discounts, for example, to groups of 50-60 people, the test-at-home price is about VNĐ600,000 per person, Sài Gòn Giải phóng (Liberated Sài Gòn) newspaper reported early this week.

HCM City-based Chợ Rẫy Hospital is carrying out antigen testing for the treatment of COVID-19 patients.

Doctor Trần Thành Vinh, head of the hospital's Department of Biochemistry, said that this method was applicable to a group of people who need testing to know if they have antibodies and if so, how much will be achieved.

After vaccination, doctors will rely on that result to re-evaluate the body's ability to respond to the vaccine. In addition, this method is also applicable to a group of patients required to be tested as a doctor suspects them of having been infected with COVID-19, with the results supporting the diagnosis.

Lecturer Nguyễn Hiền Minh from the Department of Immunology - Pathophysiology, HCM City University of Medicine and Pharmacy, told the newspaper that after naturally catching COVID-19 or having a COVID-19 vaccine, the body will produce antibodies.

Now, researchers are interested in SARS-CoV-2 antibody tests including antigen-binding antibody test and neutralising antibody test.

“Now is not the time to be sure about the correlation of antibody response levels with the body's immunogenicity with COVID-19,” he said, adding that not all service-providing laboratories had proper professional capacity and equipment to perform the above-mentioned types of antibody tests. “Antibody testing is not necessary at present because having antibodies after recovery does not mean permanent protection. Vaccination is still needed,” he said.

“Misunderstanding the COVID-19 antibody test in the blood can lead people to disregard preventive measures and make incorrect conclusions about the effectiveness of the vaccine. This may affect others' decision to vaccinate, increasing the possibility of disease spreading," said doctor Minh.

Vice director of HCM City’s Health Department Nguyễn Văn Vĩnh Châu said that antibody tests were very complicated.

Testing services offered now in the city might be general antibody tests while the antibodies that protect people from the coronavirus would be identified in the neutralising antibody test, he said.

"The health department does not yet have any guidelines on antibody testing," he said.

"In some cases, people with high concentration of antibodies in their blood still get the disease," Châu said, adding that in some countries, antibody testing was not used for all cases. — VNS