Evaluation of the LAMP method in the detection of pulmonary tuberculosis

Abstract

Background: Pulmonary tuberculosis is a bacterial infection caused by mycobacteria belonging to the Mycobacterium tuberculosis complex (Mtb). Tuberculosis is a major public health concern in the world. In 2012, 8.6 million persons developed tuberculosis and 1,3 million deaths. More than 95% of deaths from tuberculosis are recorded in low and middle income countries. In 2011 in Cameroon, 25,126 cases of tuberculosis were recorded. Currently, in our country there is only the microscopic method of early diagnosis in most health centres, which is easier and cheaper to perform, but has a low sensitivity limit of 40-60%. Amongst the techniques of nucleic acid amplification, a new method, LAMP (loop mediated isothermal amplification) used in the diagnosis of tuberculosis and easily applicable in limited resource settings has been recently implemented with sensitivity and specificity rates of 80% and 96% respectively. Our general objective was to assess the LAMP method for the rapid diagnosis of tuberculosis and our specific objectives were to evaluate the sensitivity and specificity of the LAMP method and compare the sensitivity and specificity of this method with microscopy. Methods & Materials: Our general objective was to assess the LAMP method (Loop Mediated Isothermal Amplification) for the rapid diagnosis of tuberculosis and our specific objectives were to evaluate the sensitivity and specificity of the LAMP method and compare the sensitivity and specificity of this method with microscopy. To achieve our goals, we conducted a cross-sectional and prospective study which took place from 14th April to 5th June 2014 at the Yaoundé Jamot Hospital and Centre Pasteur du Cameroon. On the basis of an informed consent, we recruited 539 suspected TB (Tuberculosis) patients to assess the lamp method. We compared the LAMP method with microscopy using culture as the reference standard Results: Results obtained showed that the sensitivity and specificity of LAMP were 83.0% and 96.2% respectively. The sensitivity and specificity of microscopy were 53.9% and 99.1% respectively. Conclusion: We concluded that the sensitivity of LAMP was higher than that of microscopy. In other words, when a patient is sick, it will be easier to diagnose using the Lamp method, than microscopy.