Context

COVID-19 is highly infective and everyday thousands of people are newly infected. Since there is no vaccine or cure for the novel coronavirus infection till today, there is a strong need for rapid, specific and sensitive SARS-CoV-2 detection technology to control and contain the virus.

Current method 

The real time reverse transcription polymerase chain reaction (RT-PCR) test is used which detects the presence of viral nucleic acids in nasopharyngeal swab samples.

Shortcomings

• The test requires complex and costly equipment. It requires extensive training for potential users.
• As the specificity and sensitivity of the test is about 95%, there is a possibility of false negative results.
• The turnaround time is about 10 hours, so that the result will be available only by the next day.
• In remote places, the turnaround time further increases depending on the distance the samples need to travel. 

The RT-PCR does not have the capacity to keep pace with the increasing demand.

Serology tests 

• These tests are also in use to detect antigens that are associated with the virus infection.
• These tests are easy to use with rapid results, as well as have minimal expenses.
• However, serology immunoassay lacks the necessary accuracy to be a reliable diagnostic test due to its low sensitivity and high false negative/positive rates.

Latest Technology RT-Lamp

• This is a one-step nucleic acid amplification method to multiply specific sequences of RNA of the coronavirus.
• Here, the RNA is first made into cDNA (copy DNA) by the usual reverse transcription.
• Then, the DNA is amplified by the LAMP technique. 

Advantages over RTPCR technology

• The RT-PCR test needs different temperatures in one cycle.
• The temperature of the solution has to be changed from 92 degrees C to 56 degrees C and again to 72 degrees C every two minutes, and this cycle has to be repeated.
• Thus, the PCR test needs expensive thermal cycler as well as the real time PCR machines.

On the other hand, the new RTLAMP technology is done at 65 degrees C, where the DNA amplification is done at a constant temperature (isothermal), so that expensive thermal cycler is not required.

The LAMP technology does not need laborious preparation as in the case of RT-PCR. LAMP is cost effective and does not need complex expensive equipment. 

Source: The Hindu