RT-LAMP- For Covid-19 Detection

In News

New technology for the detection of Covid-19 called RT-LAMP.

In-Detail

• As there is no vaccine for Covid-19 infection there is a strong need for rapid, specific, and sensitive SARS-COV-2 detection technology to control and contain the virus.
• RT-LAMP method is an ideal method for diagnosis as it is simple, speed, and cost-effective.

Current Method

• The current method for SARS-COV-2 diagnosis is the RT-PCR (real-time reverse transcription-polymerase chain reaction.
• This test detects the presence of viral nucleic acids in nasopharyngeal swab samples.
• But PCR test requires complex, costly equipment and requires extensive training for potential users.
• The sensitivity and specificity of the test is about 95% and there is a possibility of false-negative results.
• The turnaround time is about 10 hours and the result will be available only the next day.
• In the remote areas, the turnaround time may increase further depending on the distance the samples need to travel.
• To detect antigens, COVID-19 serology tests are also used.
• The serology tests are easy to use with rapid results and have minimal expenses.
• The serology immunoassay lacks the necessary accuracy due to its low sensitivity and high false-negative rates.
• For one cycle, the RT-PCR test requires different temperatures.
• The temperature of the solution has to be changed from 92 degrees C to 56 degrees C and 72 degrees C for every two minutes and this cycle has to be done repeatedly.
• So, the PCR test requires an expensive thermal cycler and also real-time PCR machines.

RT-LAMP

• RT-LAMP is a Reverse Transcriptase loop-mediated isothermal amplification technology.
• This test is a one-step nucleic acid amplification method.
• This can multiply specific sequences of RNA of the coronavirus.
• By reverse transcription, the RNA is first made into cDNA (copy DNA).
• The DNA is then amplified with the LAMP technology.
• This technique is new to the Indian IVD industry but it has been used in western countries for the past five years.
• In the RT-LAMP test, the temperature required is 65 degrees C and the DNA amplification is done at constant temperatures.
• The quantity of DNA amplified in the LAMP technology is a hundred thousand times more than in PCR.
• The final assay is possible with a simple reaction and also removes the need for costly real-time PCR machines.
• The assay is so fast in the LAMP technology and can obtain the results within 30 minutes and the positive samples are amplified as early as 10 minutes.
• This test can report with accuracy in substantially lower turnover time.
• The reagents in the LAMP tests are to be stored at 4 degrees C.
• The LAMP technology does not need laborious preparations and does not require complex expensive equipment.
• LAMP test is cost-effective and the assay can be performed with minimum skill and infrastructure.
• LAMP technology has many advantages when compared with other tests.
• The Indian Council of Medical Research validated the LAMP technology with a sensitivity of 98.75% and specificity of 100%.
• ●        The LAMP-based kits have a positive predictive value of 100% and a negative predictive value is 98.8% with an accuracy of 99.3%.
• In India, Agappe Diagnostics developed the LAMP technology and their kit has been validated by the ICMR for marketing and named it LUME Screen nCoV.

Conclusion

At present, a confirmatory, rapid, accurate, user-friendly, and low-cost molecular diagnostic method is a must to address the COVID-19 pandemic. The RT-LAMP is best for Indian conditions.