Context: Indian Researchers have developed and tested a novel, indigenous, cost-effective, real-time LAMP (rt-LAMP) assay for early diagnosis of Tuberculosis.
Relevance of the Topic: Prelims: Key facts about rt-LAMP assay test.
What is rt-LAMP assay?
- rt-LAMP (Real-time Loop-mediated Isothermal Amplification) is a molecular test that allows rapid detection of DNA.
- It utilises a one-step DNA amplification method that is able to detect TB DNA, even with as few as 10 copies per microliter in a sample.
- The test has received approval from Central Drugs Standard Control Organisation, and is waiting for validation from Indian Council of Medical Research.
Key Features:
- Low cost: Utilises inexpensive dyes (uses Syto 16, a fluorescent dye) and primers.
- Sensitivity: Detects TB DNA with as few as 10 copies per microliter in a sample.
- One-step amplification: rt-LAMP test works at a single temperature; in contrast RT-PCR requires three different temperature settings.
- Time-Efficient: With a high rate of amplification, results of positive samples can be obtained in 10-20 minutes.
- High Throughput: process up to 96 or 384 patient samples in a single run.
- rt-LAMP assay kit is developed as an open platform system which allows existing RT-PCR machines to be reprogrammed for TB diagnosis.
Why is this significant?
- As per the WHO Global TB report 2023: India is the highest TB burden accounting for nearly 27% of the global incidence.
- The National Strategic Plan for TB Elimination (2017-2025) aims to end TB by 2025 and emphasises shift towards molecular diagnostics.
Limitations of smear microscopy for TB diagnosis:
- Presently, India continues to over-rely on smear microscopy for TB diagnosis, despite:
- Low sensitivity, especially in cases with low bacterial load in a specimen.
- Inability to detect drug-resistant TB.
Other Molecular TB Diagnostic tests in India
- GeneXpert: cartridge-based polymerase chain reaction (PCR) test to detect Mycobacterium tuberculosis (MTB), the causative organism of TB. Accurate but expensive.
- Truenat: chip-based real time PCR test for the semi-quantitative detection and diagnosis of MTB.