The Blood Test, The Swab Test, and The Saliva Test
Essentially, there are three general types of COVID-19 testing produced so far. One is the rapid test, the second is the saliva test and the other is the swab test. The rapid test (also known as the anti-body test) uses blood samples. The swab test (also known as the PCR test) on the other hand uses swabs from the throat and the nasal area to check for the existence of the virus. The saliva test somewhat has the same concept as the swab test but uses saliva as a test sample.
Out of all of these, a lot of world leaders prefer using the rapid test for its speed in yielding results (thus its name). It is also cheaper and requires very little equipment to obtain results. Just like a pregnancy test, the rapid test can produce results within a few seconds to a few minutes. It is less invasive as a simple prick in the finger may do to obtain a result.
On the other hand, the swab test usually yields results only after a couple of hours. With the backlog of persons to be tested (thousands of tests per day), the results may come out only after a few days or weeks. It requires specialized equipment and the testing kit itself has a few special reagents to complete. Also, the test is rather invasive and uncomfortable. The saliva test is like the PCR swab test but is less invasive as it only uses sputum samples on a tube. Obtaining results is similar to the swab test.
Understanding False Negatives
What are false-negative results? These are samples that are from infected persons but did not manifest correctly in the tests. There are a variety of reasons for tests to provide false-negative results.
For instance, scientists do not essentially recommend using the rapid test as a preliminary means of determining whether a person has COVID-19 or not. What the rapid test measures are if a person’s immune system has already produced antibodies to resist the infection. Since the onset of symptoms varies per individual, the rate of producing anti-bodies varies as well. This could lead to the high possibility of a false negative result.
This is one of the mistakes many world leaders commit albeit unintentionally. Since they are after finding the asymptomatic carriers of COVID-19, testing a larger percentage of the population seems to be the only solution. Because rapid kits yield faster results, many world leaders would tend to focus on this rather than the accuracy of the data. Many governments do not seem to understand the dangers of false-negative results.
However, this does not mean that the swab test yields 100% accurate results. In fact, in many patients, later stages of COVID-19 infection show that there is a larger amount of virus in the deep lung cavities than the throat.
The Mass Testing Controversy
The approach for testing varies from country to country. At this point, there are no perfect guidelines when it comes to testing. Some places did not take an aggressive approach to the testing (like Japan) but the rate of infection is much lower. There are other countries that immediately did mass testing (like Taiwan, Thailand, and Korea) which led to the immediate reduction of their infected numbers. In some others (like the Philippines), the population demands mass testing, but the government does not see the necessity for it.
The question now is, should governments test their entire population? The answer may be a no, at this point. Mass testing is essential, but it is a wrong move for world leaders to decide that 100% of the population should be tested. This would lead to multiple tests going to waste.
Some people may be tested too soon to confirm an infection. Some people may be using the wrong test kit and require multiple tests to confirm. Testing the entire population multiple times can put numerous test kits to waste and create costs that should not be there, to begin with. There are even risks that a person may get the infection at the testing center itself.
The biggest threat is that false-negative results can make individuals too lax when in fact they possibly could be silent carriers of the disease. It will become counter-productive. Government mass tests to find asymptomatic patients. Asymptomatic patients may test false negative. False-negative results could lead to further disaster. On top of that, the backlog in testing centers provides such a big window of time for asymptomatic carriers to infect people in their surroundings.
Mass testing should have been done at the beginning of the pandemic. This is one of the biggest mistakes world leaders have made. At this time, efficient contract tracing may be able to detect asymptomatic carriers of COVID-19, which are now almost impossible to find.
What countries need now is to test strategically and not waste the limited number of testing kits currently available. It is important to trace contacts of positively infected individuals, to trace medical workers and front liners, and to test individuals who have symptoms. At this point, isolation may be the only way to reduce the infection until a vaccine is proven safe for the use of humans.
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