2156. To Evaluate the Role of Kit-Based Loop-Mediated Isothermal Amplification (TB-LAMP) Assay in the Diagnosis of Tubercular Lymphadenitis

BACKGROUND: Tuberculosis (TB) is the leading cause of death as a single infectious agent worldwide. In 2017, there were an estimated 1.3 million TB deaths among HIV-negative people and 300,000 deaths among HIV-positive people. The rapid and accurate diagnosis of TB in lymphnode specimens remains a challenging task today. In 2016, World Health Organization endorsed a commercial molecular assay, the LoopAMP™ Mycobacterium tuberculosis complex (MTBC) detection kit (Eiken Chemical Company, Tokyo, Japan), which uses loop-mediated isothermal amplification (LAMP) for sputum samples only. No prospective studies on LAMP in diagnosis of Tubercular Lymphadenitis in adults have been done yet. METHODS: A prospective observational study with a total of 70 lymph-node aspirate specimens from suspected cases of Tubercular Lymphadenitis with age >18 years were selected and subjected to Ziehl–Neelsen staining, LAMP and culture in mycobacterial growth indicator tube (MGIT960). The immunochromatographic test was used to confirm MTB complex (MTBC) in culture positive samples and phenotypic drug susceptibility testing was done using MGIT-960. The composite reference standard (CRS) used in the study includes symptoms, radiological evidence and follow-up of 2 months. 2 × 2 tables were made and Sensitivity, Specificity, PPV, NPV of TB-LAMP were calculated with respect to AFB smear and composite reference standard (CRS). RESULTS: LAMP assay was able to detect MTBC in 34.3% (24/70) of lymph-node specimens. Sensitivity and specificity of the assay were 100% and 69.7%, respectively, considering smear as gold standard. On comparing with CRS, the assay showed 100% sensitivity and 100% specificity in the diagnosis of MTBC. CONCLUSION: In our study, LAMP assay was found to be a promising tool for the diagnosis of Tubercular Lymphadenitis and could be used for rapid and cost-effective diagnosis of Tubercular Lymphadenitis in resource-limited settings. [Image: see text] [Image: see text] [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.