Covid in UAE: Can at-home rapid antigen tests be used for official purposes?

PCR tests are considered the gold standard for diagnosis by CDC

Rapid antigen test results carried out at home are not accepted for any official purposes in the UAE.

Doctors pointed out that the rapid antigen test is for quick assurance but should not be used alone without a clinical visit.

Rapid antigen tests are not as accurate as laboratory tests because they require more of the virus in your sample to report a positive result and come with a high risk of giving a false-negative report, say UAE doctors. This means the test can show incorrect results, and one may receive a negative report, despite being infected.

Dr Azeem Abdul Salam Mohamad, Specialist - Internal Medicine at Bareen International Hospital, Abu Dhabi, said that rapid antigen tests are more likely to return positive when more virus particles are in the body. "But it can register as a negative test when the person is only shedding a small amount of virus," he said.

There are two types of tests that are commonly used to identify SARS-CoV-2, which causes Covid-19. The first type is a polymerase chain reaction (PCR) test, also called a diagnostic test or molecular test. A PCR test can help diagnose Covid-19 by detecting the genetic material of the coronavirus.

PCR tests are considered the gold standard for diagnosis by the Centres for Disease Control and Prevention (CDC). The second type is an antigen test. "Rapid tests are Covid-19 tests that can provide results in as little as 15 minutes and don't require lab analysis. They usually take the form of antigen tests. Although rapid tests can give quick results, they aren't as accurate as PCR tests analysed in a lab," said Dr Gnei Shirazi Burnadeen Ossan, General Practitioner, Thumbay Clinic, Dubai.

"All patients giving a positive result can be safely considered Covid-19 positive, but all negatives will require a sensitive test like RT-PCR for confirmation," said Dr Naveen Tiwari, lab director, NMC Royal Hospital, DIP, Dubai.

These tests are used more for self-assurance purposes rather than any official work.

It helps detect contagiousness and can help a person self-isolate so that the virus does not spread further.

Medics have pointed out that the most common cause for a false negative result is too early exposure. Tests are recommended to be done at least 24 hours after exposure of virus or developing symptoms. "If negative and a clinician suspects Covid-19, the patient should do PCR test with investigations recommended by the attending physician," said Dr Emadeldin Ibrahim, consultant pulmonology, NMC Royal Hospital, Sharjah.

Process of rapid antigen test

During the test, you or a medical professional will insert a cotton swab into the suspected patient's nose, throat, or both to collect mucus and cells. The sample is then usually applied to a strip that changes colour if you test positive for Covid-19, said Dr Shirazi.

The antibodies on the test strip will bind to any antigen in the sample. If the antibodies bind to coronavirus antigens, a coloured line appears on the strip.

Merits of rapid tests

However, doctors also pointed out the merits of rapid tests.

• Can provide results within minutes instead of days

• Are more portable and accessible than lab tests

• Are less expensive than lab tests

• Don't require a specialist or lab

Healthcare specialists also mentioned that many airports, arenas, theme parks, and other crowded areas provide rapid Covid-19 testing to screen for potential positive cases. "Rapid tests won't catch every Covid-19 case, but they can catch at least some cases that would have otherwise gone unnoticed," added Dr Shirazi.