COVID-19 Testing, Advantages & Disadvantages of PCR test, Antigen test and Antibody test

With the COVID-19 pandemic, many people are getting tested every day for travel purposes. There are three assays that can be used to perform SARS-CoV-2 detection: pcr test, antigen test and antibody test, which have different scenarios of applicability. Among them, PCR assay is more accurate. Hospitals and other medical institutions basically use PCR tests as a test result to provide proof for patients. The SARS-CoV-2 antigen test and antibody test are also widely used in places where the number of infections is relatively high and medical pressure is excessive, which can help to complete the self-test at home.

The use of rapid screening and PCR varies from country to country. Although PCR nucleic acid testing is indeed accurate, it is more costly and takes longer to perform than antigen or antibody testing. Many countries or regions restrict PCR testing to people who are symptomatic or who have had contact with a confirmed patient in order to save money on health care costs. In the past, during outbreaks, some regions have used rapid test kits to target key areas for rapid screening and have identified many people with asymptomatic infections.

 RT-PCR Test & Antigen Test & Antibody Test

1. Nucleic acid test (RT-PCR)

Test: detects the presence of COVID-19 virus genetic material in the body

Testing time: 2~4 hours

Advantage: High accuracy, small amount of virus can be detected

Disadvantage: It takes longer time and requires professional nucleic acid testing equipment and personnel to operate

Applications: Suitable for use in areas where a small number of people have been diagnosed with covid-19, or for testing samples from suspected infected persons

2. Antigen test (rapid test reagent)

Test: To detect the presence of SARS-CoV-2 antigen in the body.

Testing time: 10~20 minutes

Advantages: short test time, rapid detection of infection

Disadvantages: lower accuracy than RT-PCR, easy to have false positives and false negatives

Applicable: Large-scale, high-risk area screening

3. Antibody test (rapid test reagent)

Test: Detection of SARS-CoV-2 antibodies in the test body

Testing time: 10~20 minutes

Advantage: detects who has been infected with the virus and detects whether there is immunity to the virus in the body

Disadvantage: It can only be detected in the middle and late stages of infection, and is less useful for triage of people at risk of infection.

Applications: to do outbreak investigation

Currently, rapid test kits are playing a key role in various countries, helping epidemic prevention authorities to find infected and suspected cases quickly. In many hospitals, a negative rapid test is now required before surgery can be performed. If all activities required people to provide negative PCR results results, it could affect people’s lives. It may even make patients miss out on a golden period of treatment, and different tests can be utilized to help specialists better covide-19 virus.

However, a negative fast screening result does not necessarily mean that there is no infection, because the sensitivity of each brand of rapid test reagent is different, and it is possible that the amount of virus is too low to be detected. So the test results need to be considered taking into account people’s exposure history and whether they have been exposed to an infected person