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The following is a summary of “A rapid and sensitive extraction-free HiFi-LAMP assay for detecting Mycobacterium leprae,” published in the March 2025 issue of International Journal of Infectious Diseases by Wang et al. 

Researchers conducted a retrospective study to assess a simple and rapid extraction-free assay for the timely and accurate detection of Mycobacterium leprae (M. leprae) to support early intervention and treatment of leprosy.  

They developed a HiFi-loop-mediated isothermal amplification (LAMP) assay to detect M. leprae. Its performance was evaluated by comparing it with qPCR and nested PCR assays using clinical samples. The extraction-free HiFi-LAMP assay was further tested using saliva samples from individuals with leprosy.  

The results showed that the M. leprae HiFi-LAMP assay demonstrated high specificity and sensitivity, with a limit of detection (LOD) of 43 copies per 25 µL reaction. For 130 purified DNA samples from nasal and oral sources, the assay achieved 100% sensitivity and specificity, exceeding the sensitivity range of 50% to 88.9% observed with qPCR. Detection rates were higher in nasal swabs than in oral swabs. The extraction-free assay using 6 µL saliva had an LOD of 11,833 M. leprae specific repetitive element (RLEP) copies per mL of saliva, provided results within 30 mins, and exhibited 66.7% sensitivity for 3 saliva samples compared to the purified DNA assay.  

Investigators concluded that HiFi-LAMP assays, both standard and extraction-free, were suitable for M. leprae detection and monitoring in resource-limited endemic areas. 

Source: ijidonline.com/article/S1201-9712(25)00058-X/fulltext