Loop-mediated isothermal amplification (LAMP) in the respiratory specimens for the diagnosis of pediatric pulmonary tuberculosis: A pilot study.
BACKGROUND
Loop-mediated isothermal amplification (LAMP) assay is a novel molecular diagnostic technique that can be used for the diagnosis of tuberculosis (TB). It is most suited for developing countries as it is rapid, inexpensive, highly sensitive, requiring minimal infrastructure, training and manpower. Studies in pediatric TB are lacking. We evaluated LAMP in the diagnosis of pediatric pulmonary TB.


METHODOLOGY
This was a cross-sectional analytical study conducted at a tertiary care teaching hospital in North India from July 2014 to June 2015 involving 60 children with suspected pulmonary TB. Respiratory specimens (sputum, gastric lavage, bronchoalveolar lavage and/or endotracheal aspirates) were collected and subjected to BACTEC MGIT 960 culture, IS6110 PCR, and LAMP assay targeting IS6110 gene of Mycobacterium tuberculosis.


RESULTS
Thirty seven children had confirmed and probable TB according to the composite reference standard (CRS). Among all the 3 tests used for diagnosis of Pulmonary TB, LAMP had highest sensitivity (37.8%) followed by PCR (27%), and culture (21.6%) when compared against the predefined CRS. Culture had maximum specificity of 100%; and PCR, and LAMP had specificity of 95-96%. The sensitivity, specificity, PPV, and NPV of LAMP against culture as reference standard were 75%, 72.4%, 42.9%, and 91.3% respectively. Similarly sensitivity, specificity, PPV, and NPV of PCR against culture as reference standard were 75%, 86.2%, 60%, and 86.2% respectively. On combining LAMP with culture, sensitivity increased to 45.7% (7.8% increase, p = 0.04).


CONCLUSION
We noted that LAMP had highest sensitivity when compared to culture and PCR and comparable specificity.
['Sreedeep|K S|KS|', 'Sethi|Sunil|S|', 'Yadav|Rakesh|R|', 'Vaidya|Pankaj C|PC|', 'Angurana|Suresh Kumar|SK|', 'Saini|Aastha|A|', 'Mehra|Nancy|N|', 'Singh|Meenu|M|']
D018893:Bronchoalveolar Lavage D002648:Child D002675:Child, Preschool D003430:Cross-Sectional Studies D004269:DNA, Bacterial D005260:Female D005751:Gastric Lavage D006801:Humans D007194:India D007223:Infant D008297:Male D025202:Molecular Diagnostic Techniques D009169:Mycobacterium tuberculosis D021141:Nucleic Acid Amplification Techniques D010865:Pilot Projects D016133:Polymerase Chain Reaction D012680:Sensitivity and Specificity D013183:Sputum D014397:Tuberculosis, Pulmonary
Respiratory specimen Children Gastric lavage Bronchoalveolar lavage Mycobacterium tuberculosis