Dr Minguita Padilla, medical team leader at Project ARK, gives us the lowdown on what we should know about the different kinds of tests available in the Philippines

Manila has been under enhanced community quarantine for nearly two months. In a pre-COVID world, that would have been nearly unthinkable. But now, it’s a necessity — a “new normal” that has been thrust upon people to accept. 

The key out of it? Testing. The World Health Organisation (WHO) has stressed the importance of mass testing in the fight to flatten the curve. One of the organisations at the helm of this movement is Project ARK, a private sector-led initiative that aims to introduce rapid antibody testing to companies and barangays in a bid to contain the spread of the virus. Today, Dr Minguita Padilla, ophthalmologist and head of the medical team at Project ARK, tells us about what there is to know about COVID-19 testing right now. 

Read also: How To Avoid Covid-19: Tips To Stay Healthy & Sanitised

What parts of the body does COVID-19 affect?

There is still so much scientists don’t know about COVID-19. What we know about it today can be disputed or reinforced tomorrow. But as of today, we know that COVID-19 doesn’t just affect the lungs. In some cases, it can affect other parts of the body including the eyes, the heart, the liver, the kidneys, and the intestines. 

Currently, the WHO has released more symptoms for COVID-19. The full list includes fever, dry cough, and tiredness. They have also added aches and pains, nasal congestion, headache, conjunctivitis, sore throat, diarrhoea, loss of taste or smell or a rash on skin or discolouration of fingers or toes to the list. 

Was the lockdown necessary?

Lockdown was definitely necessary. Without it, the number of infections would have grown exponentially. One person has the ability to infect three other people, and each of those three individuals could infect another three. 

On a macro level, what is the best way to handle COVID-19? How does our country compare?

In an ideal situation, there would have been swab tests done for everyone the moment the first few cases of COVID-19 were confirmed. Unfortunately, the country only had 2,000 test kits available until later on in the game. As of 4 May 2020, testing capacity stands at 3,000 tests a day. 

It would also be best for test results to come out within 4-8 hours but turn around time within the past few months had been 5-7 days, and sometimes as long as 2 weeks. As of 2 May 2020, there has also been a backlog of 8,000 test results yet to be released. 

Currently, as of 29 March 2021, around 30,000 tests are being conducted daily. However, government officials have been calling on to do even more tests amid the surge, as much as 90,000 tests per day

What are the different types of tests available for COVID-19?

Here, Dr Padilla makes two distinctions. First, there is the swab test also known as the real-time reverse transcription-polymerase chain reaction (RT-PCR) test. This test identifies the virus through a throat or nasal swab. The swab is then transported in ice to a laboratory where machines can convert the specimen into data that can read as positive or negative. Results come out anywhere between hours to days. 

There’s also rapid antibody testing, which is a blood test that identifies antibodies produced by the immune system. This is your body's response as it develops immunity to the virus. This test can read two kinds of antibodies: the immunoglobulin M (IgM), which is your early immune response, and the immunoglobulin G (IgG), which is your delayed immune response. 

IgM can be found in patients who are positive for COVID-19 by RT-PCR and are still infected and infectious. IgG is found in those previously tested as positive, but who have since recovered. Those with IgG can donate blood to the Philippine General Hospital for plasma therapy to help those who are currently positive but have not yet recovered. 

Since 2020, new methods of tests have also become available. Rapid antigen tests, which detect a specific viral antigen instead of antibodies, are performed using a nasal swab (versus the antibody test which uses blood). 

Saliva tests, which were only recently approved in the Philippines, work in the same way that nasal swab tests do as COVID-19 particles are present in both saliva and respiratory droplets. Using lab tests to identify viral genomes, saliva tests can be very accurate when done properly.

What should you do after you use a rapid antibody test kit?

That depends on your results. Keep in mind that IgM is found in patients who are SARS-COV-2 positive. IgG is found in those previously tested positive, but who have since recovered. 

  • If you have no symptoms, are negative for IgM, and positive for IgG then you are probably infected and developing immunity. It is best to self-isolate. 
  • If you have no symptoms, are positive for IgM, but are also positive for IgG, then it’s best to self-isolate for another 14 days, take another rapid antibody test after that time, and check the results again.
  • If you have no symptoms, are positive for IgM, and are negative for IgG, then you are considered infected. It is best to self-isolate for 14 days and take an RT-PCR swab test.
  • If you have no symptoms, are negative for IgM, and are negative for IgG then you’re not likely to be infected but may consider taking a retest after 7 days.
  • If you have symptoms, then it is always best to self-isolate. 

What are the advantages and disadvantages of these tests?

Speaking first on the swab test or the RT-PCR: the advantage is that this test can detect the virus up to 2 days before symptoms start to appear. The disadvantages, however, include the lengthy processing time in the country, as well as the possibility for human error in either of the processes involved (swabbing, transporting, extracting, reading). The RT-PCR can also pick up on the remnants of the virus that are no longer viable — as in the case of a confirmed patient who has recovered — leading to false positives. 

The advantage to the rapid antibody test is that it’s quick, relatively inexpensive (should cost around Php400 - Php700), and easy to use. However, the disadvantage lies in the fact that accuracy depends on the sensitivity of the kit itself so the brand and manufacturer are quite important. It may also result in false negatives if one tests too early and the immune system has not had time to generate antibodies. 

The advantage of a rapid antigen test is in its name: rapid. Results come quickly and for people in less accessible areas, it's still a great tool to mitigate infection rates. However, it does have lower sensitivity when compared to the RT-PCR, meaning it's not as accurate.

For saliva tests, the biggest advantage is the fact that it's non-invasive. The con is that the amount of saliva needed may be more than a person can readily provide. There's also the potential for it to be less sensitive than RT-PCR tests. 

Who should be tested?

Unfortunately, due to lack of test kits, there is a hierarchy to follow in terms of who should be tested. Those that must be prioritised are: 

  • All asymptomatic or symptomatic persons who have been in close contact with a confirmed COVID-19 patient
  • All asymptomatic or symptomatic persons who have been in close contact with a probable confirmed COVID-19 patient. According to the WHO, probable confirmed patients are suspect patients who have been tested for COVID-19 but with inconclusive results. Another definition for a probable confirmed patient are those who have tested positive for COVID-19, but the test was not conducted in an officially accredited laboratory for confirmatory testing. A suspect case for whom testing could not be performed (for any reason) is also a probable confirmed patient. 
  • All symptomatic persons
  • Frontliners
  • Those with high-risk including diabetics, hypertensives, the immunosuppressed, the obese, and the elderly 

Are we on our second wave?

Last 21 March 2021, the Department of Health officially announced that the Philippines was on its second wave, almost exactly a year since the first wave started. In previous pandemics, such as in the 1918 Spanish Flu pandemic, the second wave has usually proved to be deadlier than the first. 

In our current context, part of this wave might be explained because of the presence of new variants which, while not necessarily deadlier, are much more transmissible. And the spike is worrying. In the past few weeks, the Philippines had broken its own record of cases multiple times. In 2020, our highest number recorded was just shy of 7,000. Now, our record cases stand at 9,808 a day, less than 200 shy of 10,000. This prompted a one-week reversion back to ECQ during Holy Week to curb more potential cases from travellers around the country.

Last updated: 29 March 2021

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