DIFFERENT METHODS OF TESTING COVID-19

 

RT-PCR	MOLECULAR DIAGNOSTIC TEST
ANTIGEN TEST
ANTIBODY	SEROLOGICAL TESTS
MASS SPECTROMETER

 1)    (RT-PCR) (MOLECULAR DIAGNOSTIC TEST)

(Real time Transcription- polymerase chain reaction) is a nuclear-derived method for detecting the presence of specific genetic material in any pathogen, including a virus.(RT-PCR) is a sensitive in vitro method and has a crucial role in medical science and biomaterial fields.

        Covid-19 real time reverse transcription polymerase chain reaction of RT-PCR is prescribed to detect SARS-COV-2 or corona virus in respiratory track through a nasopharyngeal swab collected from a patient. It detects the virus even if the amount or content of the virus in the body is less. It is the most widely used method for detecting the covid-19 virus.

The time duration for the testing process is approximately four to eight hours and for the results to arrive, it may take up to one or two days.

Amongst all the methods used to test covid-19, this is the most expensive one. Initially, the cost of the test was capped at Rs. 4,500 by the ICMR (Indian council of Medical Research)

(RT-PCR) is claimed as the ‘Gold Standard’ for all viral infection. 

2) ANTIGEN DIAGNOSTIC TESTS

Antigen diagnostic tests are designed for the rapid detection of SARS COV-2. They are more cheaper than the molecular diagnostic test. They produce results in about 15 minutes.

While molecular tests detect viral genetic material, antigen tests detect specific proteins on the surface of the virus. The samples are collected in wing nasal or throat swabs. The swab is then placed into a tube with special chemicals to expose the protein, and the sample is dispensed into a cassette that is placed into the testing device to get your results.

Compared to molecular tests, they are not so sensitive, as sometimes they can give false results. But if you test positive, there are high chances of you getting detected by corona virus. If your test comes back negative you are likely want  to confirm your negative result wing molecular test (RT-PCR).

 3)  ANTIBODY (serological tests)

Serological tests rely on detecting antibodies in a blood sample, usually obtained through a simple finger pick or blood draw.

When a person is exposed to the virus his body develops antibodies, which can take several days to over a week. Antibodies are proteins your body makes when mounting a response against invading germs.

 

The presence of immunoglobulin M (IgM) antibodies indicate recent exposure to COVID-19, while the presence of immunoglobulin G (IgG) antibodies indicate later-stage infection. The rapid response serological tests typically use a technique called enzyme-linked immunological assay (ELISA), which detects the presence of these antibodies to the coronavirus.

 

Sometimes this method of   testing can give a false result as it can take several days to week for the body to develop an antibody response to the virus.

 4)  Mass spectrometer.

Mass spectrometer takes less than 3 minutes time for the detection of virus.

This new method relies on detecting the presence of two peptides unique to SARS-COV-2 and not seen in any other corona virus or other viruses. One of the peptides is the spite protein and the other is a replicase protein.

The result have been published in the journal of proteins and proteomics.

The mass spectrometer is expensive but it would cost only about Rs. 100 per test.

 

REFERENCE;

https://www.thehindu.com/

https://theprint.in/