COVID-19 Tests: Which One Should I Take?
The COVID-19 pandemic has undoubtedly changed the way we live. From traveling abroad to things as simple as getting a haircut, we now have to make various adjustments to our daily routines. While dangerous, this disease caused by the SARS-CoV-2 virus can actually be prevented from spreading. One way to do this, other than obeying health protocols, is by getting tested.
At present, there are four types of COVID-19 tests available in Indonesia: the rapid antibody test, the rapid antigen test, the ECLIA test, and the real-time RT-PCR test. Naturally, it can sometimes be confusing to tell these four types of tests apart. If you’ve been wondering which test you should take, let us take you through a quick COVID-19 test comparison.
Rapid Antibody Test
The rapid testing method that is currently commonly used in Indonesia is a type of antibody test that’s mainly used for epidemiological research. Antibody tests, also known as serology tests, are used to detect certain antibodies in your blood. These antibodies are proteins produced by the immune system to fight an infection from a virus or bacteria. From the presence of certain antibodies within an individual, healthcare workers are able to deduct whether or not an infection has taken place in the past.
The COVID-19 rapid antibody test detects two antibodies:
Immunoglobulin M (IgM): Found mainly in blood and lymph fluid, this is the first antibody the body makes when it fights a new infection. It acts as the first line of defense against infections before more antibodies are produced.
Immunoglobulin G (IgG): This is the most common antibody. It's found in blood and other body fluids, and protects against bacterial and viral infections. IgG can take time to form after an infection or immunization.
How it works:
1. Blood sample is drawn from the fingertip or the vein.
2. Blood sample is placed on a portable test kit.
3. A buffer liquid is dropped on the test kit to detect antibodies.
4. Test result is visible on the kit within 10 – 30 minutes.
According to the COVID-19 Task Force, if your test comes up as reactive, you will be required to do an RT-PCR test at a lab or a hospital. If the test is non-reactive, you will be required to do another rapid antibody test in 10 days to confirm the results. This is because IgG and IgM antibodies can take several days or weeks to develop, so taking the test again after 10 days will give you more accurate test results.
In Indonesia, the rapid antibody test remains one of the most affordable and widely available tests and mainly serves as an initial screening to decide whether further testing is needed. However, the false negative rate is higher and results may vary greatly depending on which test kit is used, so make sure you get it from a trusted hospital or clinic.
For this type of test, the best time to take it is about 7 days or more after exposure, as there would already be enough antibodies in the sample.
Rapid Antigen Test
Another test available for COVID-19 testing is the rapid antigen test. Also known as the rapid swab test, this diagnostic test detects the presence of an antigen — a protein on the surface of a virus that triggers your immune system to produce antibodies against it. The result will directly show if you have an active virus infection or not.
How it works:
1. The mucus sample is swabbed from the nose or throat and mixed with a lysis buffer.
2. The sample is placed on a strip, card, or slide that contains reagents.
3. The amount of fluorescence detected indicates the concentration of viral antigens in the sample.
Disclaimer: This process may vary depending on the type of test kit used.
The sample collection process takes only a few minutes and results typically come out in an hour. If you test negative, some providers may recommend you to confirm the result by taking an RT-PCR test or wait for 10 days to take a rapid antibody test. However, while positive results are highly accurate, there’s still a considerable chance of false negatives. As such, negative test results must still be confirmed with an RT-PCR test.
Antigen levels in samples collected more than 5 days after the onset of symptoms may drop below what the test kit can detect, so it’s best to take the test as soon as you show COVID-19 symptoms.
ECLIA (Electrochemiluminescent Immunoassay) Test
Like the rapid antibody test, the ECLIA test is another type of antibody or serology test that is used to detect the presence of IgG and IgM in an individual. ECLIA is a lab-based test which involves an autoanalyzer machine and software to perform the sample analysis. The sample collection process takes approximately 10 – 15 minutes and you can get your result 1 or 2 days after taking the test.
How it works:
1. Blood sample is drawn from the vein in the arm.
2. Blood sample is collected and taken to the lab for examination.
3. Blood sample is processed inside a machine to check for antibodies.
Reactive test results mean that you may have been infected with SARS-CoV-2 at some time in the past and should take an RT-PCR test.
Compared to the rapid antibody test, the ECLIA test is claimed to be more sensitive because it can detect antibodies in lower levels. This test also falls in the same price range as the rapid antibody test, making it relatively affordable to many. However, ECLIA test results are not currently listed as eligible for travel requirements in the Ministry of Health’s Circular Letter No.HK.02.01/MENKES/382/2020, so if you’re planning to travel out of town, a rapid or RT-PCR test is a more suitable option.
Because antibodies take time to develop, this type of test is more accurate if done at least 7 days after exposure to the virus.
Real-time RT-PCR Test
The real-time reverse transcriptase polymerase chain reaction (RT-PCR) test is a type of molecular test — tests that directly analyze the presence of a foreign genetic material within your system. There are two kinds of genetic materials:
Deoxyribonucleic acid (DNA): Two-strand molecules carrying the genetic code that determines the characteristics of an organism.
Ribonucleic acid (RNA): One-strand molecules that work as messengers, carrying instructions from DNA on how a cell should replicate.
In some viruses, including SARS-CoV-2, the genetic information is encoded in the RNA rather than DNA. Using real-time RT-PCR, scientists convert the RNA found in your sample into DNA in a lab. They will then amplify these DNA to detect traces of the virus’s genetic material.
How it works:
1. Mucus sample is swabbed from the nose or throat.
2. Sample is mixed with a lysis buffer to break down the cell’s wall and extract the genetic material.
3. The mixture is placed inside a RT-PCR machine to see if the coronavirus is present.
Due to its high sensitivity, the RT-PCR test is the gold standard for detecting active SARS-Cov-2 infections. However, although the sample collection itself only takes 5 – 10 minutes, you may need to wait up to a week for the results, as samples need to be sent to a lab with adequate processing facilities. Since the technology required to perform this test is costly and has to be imported, the RT-PCR is also quite expensive.
It is worth noting that the concentration of the virus may be too low for detection if you're newly infected, so the best time to test is 5 – 7 days after exposure to the virus.
What can the test results be used for?
In order to inhibit the spread of COVID-19 in Indonesia, there are various new regulations in place that affect how we do certain activities. Here are some that require you to present proof that you are healthy and free from COVID-19:
According to the Circular Letter No.9/2020 published by COVID-19 Task Force, there are now certain conditions you have to comply with before traveling outside the city by public transportation. These are the requirements:
Present a negative PCR test result or non-reactive rapid test result.
Present a valid ID card.
Present a medical certificate stating you are free from influenza-like illness issued by a doctor from a clinic or hospital in an area with no rapid and/or PCR testing facilities.
Note that these requirements do not apply to drivers and passengers of private vehicles and do not affect your day-to-day trips, such as commuting to work or grocery shopping.
Getting Certain Medical Care
According to a letter issued by Kementerian Kesihatan Malaysia (KKM), you are not required to take a COVID-19 rapid test before receiving medical care. That being said, if you are showing COVID-19 related symptoms, some hospitals may need you to undergo a rapid or PCR test before receiving certain high-risk treatments like surgeries.
Getting Beauty Treatments
Apart from requiring their staff to take periodic rapid tests, certain beauty clinics also require the visitors to present non-reactive rapid test results before being treated. This applies to some treatments that present a high-risk of transmission or require a lot of physical contact.
How do I take the test?