Performance of a lateral flow test for the detection of leprosy patients in India

Leprosy is the result of chronic infection of skin and nerves with Mycobacterium leprae. Many M. leprae-specific as well as Mycobacterium genus-specific antibodies are found in the sera of leprosy patients. Although such antibodies are not known to be protective, their presence in the sera of leprosy patients may be employed for detection of M. leprae infection. Thus far, serological tests using phenolic glycolipid-I (PGL-I), a unique component of M. leprae (Hunter & Brennan, 1981), have been most commonly used for detection of M. leprae infection (Oskam et al., 2003). The organism is known to induce, predominantly, an IgM type of antibody response (Cho et al., 1983). Of the various potential serological assays, ELISA-based tests have been most commonly assessed for their value in the diagnosis of leprosy, in monitoring the effectiveness of chemotherapy, in detecting the emergence of relapse, in identifying patients with a high risk of reactions during therapy and in monitoring changes in the magnitude of M. leprae infection in a population (Oskam et al., 2003). Although ELISA is a versatile tool, it has some drawbacks such as its requirements for trained personnel, expensive equipment and consumables that need to be stored in cool conditions. All these are discouraging for the settings where leprosy is most prevalent. Moreover, it takes nearly 1 day before results are available. Hence a more convenient, rapid, robust and easy-to-use test is desirable.