Molecular diagnostics is a branch of medical science that has revolutionised the way we detect and diagnose diseases.
Most molecular diagnostic assays work by identifying the presence of unique genetic material (DNA or RNA) that can be targeted and amplified. These tests are useful in detecting a wide range of pathogens, including COVID-19, Influenza, tuberculosis, and sexually transmitted diseases.
Nucleic Acid Amplification Tests (NAATs) are important tools in molecular diagnostics. NAATs rely on extracting the genetic material from the sample and then copying, or amplifying it many times so that it can be detected more easily. Two of the most popular NAATs are Loop-mediated Isothermal Amplification (LAMP) and Polymerase Chain Reaction (PCR).
PCR & LAMP Compared
PCR is the most widely used NAAT in molecular diagnostics. Invented in 1983, PCR involves amplifying a specific DNA signature through a series of heating and cooling cycles.
LAMP, a next generation NAAT technology, was discovered a decade later and is increasingly adopted due to several advantages over PCR.
Similar to PCR, LAMP also amplifies DNA a billion times but achieves this faster due to its operation at a single, constant temperature. This feature makes LAMP an invaluable resource for point-of-care testing, particularly in resource-limited settings.
LAMP and PCR are valuable molecular diagnostic tools with unique strengths and weaknesses. Let’s take a closer look by comparing them with respect to SARS-CoV-2 (COVID-19) diagnosis.
| Feature | PCR | Sentinel RT-LAMP |
|---|---|---|
Sensitivity
Including Asymptomatic1 | 95-100% | 91-98%2 |
Total Turnaround Time
Sample Collection, Inactivation, Testing, & Reporting | 5-72 Hours | ~40 Minutes3 |
Scalable Collection | Usually nasal swab, administered | Saliva/nasal, self-collected |
Daily Throughput | Up to 3,000 tests/day4 | Up to 100,000 tests/day |
Hourly Throughput | ~125 tests/hour | Up to 5,000 tests/hour |
LAMP and PCR are powerful molecular diagnostic tools that have transformed our ability to detect and diagnose diseases.
While PCR remains the gold standard in molecular diagnostics, LAMP offers a rapid, cost-effective, and accessible diagnostic method for point-of-care or low-resource settings. This makes it ideal for large scale screening in hospitals, senior care homes, military bases, cruise ships, religious event centres, and essential workplaces.
Sources
- Dinnes et al, Rapid, point-of-care antigen and molecular-based tests for diagnosis of SARS-CoV-2 infection. Cochrane Database of Systematic Reviews 2020, Issue 8..: CD013705. DOI.
- 94-98% Sensitive across infectious viral load range – equivalent to Cycle Threshold (Ct) < 33. Dewhurst et al., (2022) Validation of a rapid, saliva-based, and ultra-sensitive SARS-CoV-2 screening system for pandemic-scale infection surveillance. Sci Rep.
- The entire end-to-end screening process, including ID/Barcode scanning, collection of samples, inactivation, Sentinel processing and secure reporting of data.
- Based on real-world testing of NP Swabs run on automated IVD instruments (e.g. Cobas 6800, Alinity, Panther).
