Comparison of Cross Priming Amplification and Loop Mediated Amplification for Tuberculosis Detection in an Integrated Diagnostic Device

Abstract

Tuberculosis infects one out of three individuals worldwide. In order to control tuberculosis infection, accurate diagnostics are needed at the point-of-care. An ideal point-of-care diagnostic for tuberculosis would include an integrated system for lysis of the bacteria, extraction of the DNA from the bacterial lysate and the sputum, and detection of a specific biomarker. We compared the use of two different isothermal amplification methods, cross priming amplification (CPA) and loop mediated amplification (LAMP), for the detection of tuberculosis within a previously developed extraction cassette designed for low resource areas. Under ideal laboratory conditions, CPA and LAMP had a limit of detection of 500 copies and 50 copies respectively. As part of an integrated system, CPA and LAMP detected a concentration of bacteria at 1X103 cells/mL at 46 ± 5.8 minutes and 57 ± 4.6 minutes. For the integrated system of tuberculosis detection, CPA generates faster results. However, LAMP was shown to have a lower limit of detection and more specificity under ideal conditions. Overall, this study supports the continued investigation of using isothermal amplification methods combined with a low resource extraction cassette as a point-of-care diagnostic test.