Chapter 8 - Loop-mediated isothermal amplification as a point of care diagnostic tool

Abstract

Since the advent of nucleic acid amplification in the 1980s, polymerase chain reaction (PCR) has undergone extensive development for broad range clinical applications, especially in the realm of genetic testing, diagnosis of infectious diseases such as tuberculosis, hepatitis, and hereditary diseases. The genetic testing typically involves extraction of nucleic acid from the samples, amplification of the gene followed by detection. To overcome the requirements for expertise and expensive equipment, which can hinder convenient testing at diverse locations, a novel gene amplification method, called loop-mediated isothermal amplification (LAMP), has been pioneered and known for its rapidity, simplicity, and remarkable specificity. LAMP is a molecular diagnostic technique that has gained attention in recent times for its potential as a point-of-care (POC) diagnostic tool. LAMP is a unique, sensitive, simple, and rapid method for the detection of various diseases causing pathogens and viruses, including helminths. It has been applied for the detection of Plasmodium falciparum in plasma samples and Neisseria meningitidis in cerebrospinal fluid samples, demonstrating its potential for POC molecular diagnosis of infectious diseases in resource-limited settings. LAMP has also been used for the detection of Salmonella spp. in food applications, showing robustness and comparable performance to PCR and real-time quantitative PCR. The principle of LAMP involves the use of specific primer sets consisting of four to six primers that recognize different regions in the target DNA sequence, providing high sensitivity and specificity. The reaction occurs at a constant temperature, eliminating the need for precise thermal cycling required in PCR, which reduces the time-to-result and minimizes power requirements for POC applications.