Development and evaluation of rapid and specific sdaA LAMP-LFD assay with Xpert MTB/RIF assay for diagnosis of tuberculosis.

There is need for rapid and cost-effective diagnostic test for tuberculosis. The present study was carried out to design a Loop-mediated isothermal amplification (LAMP) assay combined with lateral flow dipstick (LFD) as a point-of-care method for diagnosis of TB. LAMP assay targeting sdaA gene combined with LFD for sequence specific detection was standardized in user friendly and rapid format. It does not require sophisticated instruments and shows visual results instantly. The LAMP-LFD assay was validated using culture confirmed specimens. The assay was evaluated in a cross-sectional study using respiratory specimens collected from patients in Delhi, India and it showed high concordance with GeneXpert MTB/RIF assay. Lateral flow dipstick method has provided an excellent detection format with LAMP method. The LAMP-LFD assay showed high diagnostic accuracy in comparison to other methods and can be used as a point-of-care test in cost-effective manner.