Context: Recently, India's  first disease diagnostic laboratory is ready to be launched. The mobile laboratory was constructed under the scheme Atma Nirmar Bharat Abhiyan .

Key Points

• The laboratory aims to promote and support the idea of becoming self sufficient in difficult times. It was constructed in a record time of 8 days.
• The laboratory was built with the assistance of Department of Biotechnoogy.

About the lab

• The first infectious disease diagnostics lab is a BSL-2 facility that has Biochemistry analysers, real-time reverse transcription-polymerase chain reaction (RT-PCR), and on-site Elisa.
• Elisa is a technology designed for quantifying and detecting soluble substances such as proteins, antibodies, peptides, and hormones.
• The newly built disease diagnostics lab can easily test RT-PCR about 50 per day and ELISA about 200 per day.

About Enzyme-Linked Immunosorbent Assays (ELISAs)
They are the most widely used type of assay. They have evolved from viral lysate tests which contain recombinant protein and synthetic peptide antigens:

• They have high sensitivity and specificity.
• ELISAs are designed specifically for screening large numbers of specimens at a time, making them suitable for use in surveillance and centralized blood transfusion services.
• ELISA test kits have routinely been used to detect HIV infection in patients.

About RT-nPCR Test

• It does not depend on RT-qPCR (testing approved by the ICMR) but uses standard RT-PCR as part of an endpoint assay (i.e. to measure biochemical activity of a sample).
• It has been developed on a low-cost and low-tech model.
• This new test is awaiting approval from the Indian Council of Medical Research (ICMR).

About RT-qPCR Test

• The ICMR has recommended only Reverse Transcription Polymerase Chain Reaction (RT-qPCR) test for novel coronavirus testing.
• PCR is an enzymatic reaction used to amplify DeoxyRibonucleic Acid (DNA).
• Unlike conventional PCR, which relies on end point analysis, qPCR enables the analyst to monitor DNA amplification in real time, as the reaction proceeds.This allows quantification of DNA.
• However, coronavirus is made up of Ribonucleic Acid (RNA). Therefore to detect coronavirus, RNA is converted into DNA using a technique called Reverse Transcription (RT).

Difference between RT-qPCR and RT-nPCR

• In RT-qPCR, the viral RNA is quantified, whereas in RT-nPCR, the viral RNA that nests is studied.
• RT-qPCR is costly, takes longer, needs special apparatus and can be performed only in a lab with sophisticated equipment. It requires a real time thermal cycler, which is an expensive instrument.
• RT-nPCR is economical, can be tested on a large scale, does not require special apparatus and can be done in a lab with basic equipment. It needs a simple PCR machine.
• Further, the CCMB scientists found a high percentage of false negative cases while comparing RT-qPCR with the new test.
• The RT-nPCR test was able to identify 90% of the detected samples as positive by RT-qPCR.
• It also detected 13% samples as positive among samples that were negative by the standard RT-qPCR test (likely false negatives).