With the recent backlash against the use of rapid testing, it is important to bear in mind that the actual purpose of rapid tests is not to diagnose COVID-19 but to monitor its spread and prevalence.
Rapid test kits are not meant to be standalone diagnostic products. These are used in conjunction with ELISA and PCR tests. Rapid test kits are generally high in specificity but lower in sensitivity. This means that the test kits are more likely to produce false negative than false positive. For the absolute diagnosis of COVID-19, PCR testing is the most reliable diagnostic process.
Rapid tests are for disease surveillance.
As advised by health experts, rapid testing should not be conducted only once. Instead, it must be done at a regular succession, preferably once every two weeks. Rapid testing is reliant on the timeliness of sample collection. Antibodies cannot be detected during the earlier days of infection. In our current situation, it is also uncertain if we’ve come across COVID-19 positives because some of them are asymptomatic. A bi-monthly testing would detect the real antibody from an exposed person since this time frame captures the virus’ development in possible COVID-19 carriers.
For targeted spaces such as workplaces and barangays, rapid testing once every two weeks is instrumental in monitoring the trends of the virus within the community. There’s a higher chance of detecting positive cases and implementing crucial isolation and contact tracing protocols. Rapid test results must not be treated as mere work clearance for employees to be conducted once before returning to the workforce. Companies must be mindful that regular testing is a more effective disease management initiative.
Rapid tests are meant to support PCR testing.
Our country has a limited PCR testing capacity. Not every region in the Philippines has access to an accredited laboratory. As a highly contagious disease, the COVID-19 has spread exponentially in the recent months that PCR laboratories are struggling to accommodate all the incoming tests. Not every business has the capacity to have their employees regularly swab tested either. It is irresponsible to rely only on our straining laboratories to take on the entire weight of our country’s COVID-19 testing.
Rapid testing provides a bridge towards testing accessibility. It should, as we’ve said, not be treated as a confirmatory test but as a companion test to PCR. Its significantly more affordable cost makes rapid test kits a suitable means to augment the testing needs and be utilized for surveillance purposes. It should also be noted that rapid kits detect antibodies, which PCR tests tend to miss. Blood samples can provide important diagnostic information that swab tests cannot since the antibody stays longer in the blood than the virus. These two testing methods trade off and make up for the limitations of the other.
Once again, the public must be reminded that rapid testing alone is not effective for COVID-19 diagnosis. Receiving a negative rapid test result once does not mean you are cleared of the virus. You may be in the early stages of infection. It also does not make you immune from the disease. You may come in contact with a carrier in the near future. To truly maximize our rapid test kits, local governments and private companies must use them for regularly scheduled screening tests.