COVID-19 Testing: PCR or Serology Test
Currently, many researchers are looking to PCR (polymerize chain reaction) testing and Serology testing techniques to test individuals for COVID-19. However, before a decision about whether to use PCR testing versus Serology testing, it is essential to know what the technique, differences, advantages and disadvantages. Both techniques have caveats, and as the health crisis unfolds, researchers are searching for alternative ways to screen for COVID-19.
There are many people who doubt that using PCR methods to prove a case is a good idea. They think that there is something improper about the use of a biological polymerase to test DNA, and this method is not scientific. Even the term, PCR, for those people may cause them some issues. To help in solve their concerns about the reliability of PCR, here are some facts about the test.
About PCR Testing
PCR is a technique where millions of copies of a specific DNA are made. These copies allow scientists to take a tiny sample of DNA and magnify and exponentially amplify them in cycles and series with changes in temperature. The technique involved genetic testing, which included a description of agents and early samples of DNA.
The polymerase is a complex protein. It can react with the DNA in a laboratory setting by forming a short chain of polymerase which will then make its way through the DNA strand. This DNA sequence is then amplified, and after a bit of time, it becomes more detectable. Because of the large amount of DNA, this procedure is usually used to test hundreds to thousands of fragments of DNA.
The Polymerase chain reaction has helped scientists in many different ways. From trying to determine the age of fossils to looking for the genetic makeup of a person, the testing procedure is a proven process. Here are some of the ways it has been useful.
The Use of PCR Testing
PCR tests are used to detect antigen, not antibodies or the body’s immune response. Viral RNA will be in the body before symptoms or antibodies form, so if the PCR test detects the viral RNA, it can determine whether or not an individual has the virus.
PCR tests can be intensive, with multiple stages where errors can occur between analysis and sampling. False negatives occur approximately 30% of the time, which mean they are more useful for verifying the infection.
PCR History
PCR testing was invented by Kary Mullis in 1983. Mullis worked at for Cetus in Emeryville, California. At Cetus, Mullis was responsible for making chains of DNA for other specialists. Cetus was among the first Biotechnology firms. In 1993, Mullis and Michael Smith shared a Nobel Prize in chemistry.
How does PCR Testing work
PCR tests are performed by identifying the genetic material found in viruses. There are several ways a healthcare worker can collect a sample.
1. A swab in the throat
2. A liquid sample from the respiratory tract
3. Take a tool sample.
When the sample arrives reaches the lab, scientists extract the nucleic acid, which contains the genome of the virus. Then, scientist amplifies a specific area of the genome by applying a technique called a transcription-polymerase chain reaction. This reaction gives the scientist a huge sample to compare to COVID-19.
About Serology
Most practitioners of PCR agree that it is a better method of detecting a viral infection than Serology. Serological tests may take a longer time to conduct and may require multiple exams to come up with a complete diagnosis. Because of these disadvantages, PCR testing is becoming more popular in many cases.
Serological testing can measure the viral load in the blood. Some people do not have enough antibodies to be able to accurately measure their viral load. Using PCR testing instead can give a more accurate measurement.
Negative results from both tests are not always conclusive. The tests may both confirm the presence of the virus, but it may not necessarily mean that someone was exposed to it. Therefore, PCR testing is used to rule out exposures that are not direct and to help reveal the virus.
Serology testing
The first thing that comes to mind when thinking about serology testing is the blood test. Most people associate it with a blood test, which means it provides the ability to tell whether a patient has certain substances in their body. Before blood testing came around, serology was one of the few tools that were used to diagnose diseases through analyzing blood.
The Use of Serology Testing
Serology uses sera from animals to measure viral load. Because of the potential differences in the way these methods work, it is important to know what it means to get a positive or negative result. If a sample is found to be positive for COVID-19, it indicates that an oral dose was administered. Serological tests would indicate if the virus was in the bloodstream. These were usually done through a catheter insertion and an introduction of liquids (such as blood) to the infected area. This is a very crude method, with some positive and negative effects, but it worked well.
As time passed, scientist came up with a better way to detect illnesses in the body, with the development of molecular-level testing through DNA testing and other methods. The fact that serology was always a crude and poor test also meant that there were only a handful of serological tests out there and everyone had the same disadvantages.
The disadvantages of serology testing is the fact that all blood samples are tested. The cost of testing is very high, so there will be many cases where the test will only give a positive result and not a negative one. Even if a sample is negative, this could still lead to a negative test result in other areas of the body.
It is very common for negative and positive results to come back to the same test. A positive result will indicate that the virus was in the system at the time of the test, but it may also indicate that there was no direct exposure. If this is the case, a positive result will not necessarily mean that someone did not come into contact with the virus.
