Types of Tests for Detecting Coronavirus

June 9, 2020
Currently, there are basically three different types of tests for detecting coronavirus. The most well-known of the three is the rapid test, which is very practical but less trustworthy. Scientists are working around the clock to offer faster and more reliable tests.

The work to develop tests for detecting coronavirus is one of the most crucial issues when it comes to the current pandemic that’s affecting our world. There’s evidence that suggests that conducting thousands of tests every day can help impede growing contagion.

However, scientists have encountered various difficulties when it comes to applying the different types of tests that confirm this illness. The most notorious problem is that the most reliable tests take longer in giving results, while the fastest tests have several faults.

There are several advances in this sense and experts believe that they’ve resolved the described difficulty to a large extent. What’s more, they expect that, by next winter, they’ll have developed a highly efficient test with the latest technology. But for now, let’s take a look at the tests for detecting coronavirus that are available today.

RT-PCR, one of the types of tests for detecting coronavirus

Of all the tests currently available for detecting coronavirus, this is the most complete and reliable. Up until now, it has emitted the fewest number of errors in final diagnostics. For this same reason, it’s the test that the World Health Organization (WHO) has recommended.

The test consists of introducing a swab, generally in a patient’s nose, although it’s sometimes done with the throat. With the swab, medical personnel takes a sample, which then goes to a specialized lab. Taking the sample takes 10 minutes, after which the virus is deactivated in a process that takes between 10 and 15 minutes.

Then, technicians extract the genetic material from the sample and process it with special equipment. The entire process takes approximately 4 hours, and this long lapse is its main flaw. Currently, scientists are working to find methods that allow for the shortening of the duration of this test. They believe that they’ll soon have RT-PCR tests available that provide results in just an hour.

The RT-PCR test for coronavirus.
In order to carry out this test, a swab is inserted into the nose or throat in order to take a sample.

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Antigen test

Among the tests for detecting coronavirus, the antigen test is the fastest, and is also the most widely used test in the world right now. The weakest point with this test is its reliability. On the one hand, some manufacturers have had deficiencies in the production of these tests. At the same time, they’re not very efficient in cases where individuals are incubating the virusIn general, a second test is necessary.

This test works in a similar way to a pregnancy test. As with the RT-PCR test, samples are taken from the nose or throat, but this time they are placed on a strip of paper. Then, it’s just a matter of waiting for the same paper to reflect bands of colors that indicate whether the test is positive, negative, or inconclusive.

The antigen test takes only 10 to 15 minutes from start to finish. It’s reliable in patients that have a high viral load. Experts believe that the sensitivity of this test is barely 30 % and therefore leaves room for a lot of doubts and false positives or false negatives. What’s good about this test is that people can do them at home without medical supervision.

Serological tests for detecting coronavirus

All things being equal, this test is similar to the one used to find out a person’s blood type. It involves the extraction of a blood sample, but just a small amount is necessary. Just as with the antigen test, the sample is placed on a paper strip. The strip changes color if it detects antibodies that the body produces in an infected individual in order to fight against the virus.

This is a very fast test that only takes 10 or 15 minutes. However, it’s reliability is limited. Patients only develop antibodies six to eight days after contracting the infection. At the same time, it doesn’t distinguish whether patients are still infected, or already immune to the virus. It’s most often used in epidemiological studies.

The serological test for coronavirus.
The serological test for coronavirus is a fast test but isn’t 100 % reliable.

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Nanotechnology-based optical biosensors

This test is still in the test phase but it’s quite advanced. It consists of a biosensor, similar that those that people with diabetes used to measure their blood sugar. This biosensor measures a little over an inch and contains a special chip.

The test involves putting a sample from the patient through the chip. If this sample contains the SARS-CoV-2 virus, then it will produce a change in the light properties of this device. The entire process takes an hour. The first half hour is to formulate the diagnosis and the second to confirm the results.

One of the advantages of this test is that performing it doesn’t require highly specialized personnel. At the same time, it provides very reliable results. However, experts believe that it won’t be ready until the end of 2020.

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