Tuberculosis Drug Treatments -- Line Probe Assay
Currently, one of the best ways to detect TB as well as multi-drug resistant TB (MDR-TB) is through a platform called Line Probe Assay (LiPA). Rather than relying on visualizing bacteria under a microscope (as is done in acid-fast smear), LiPA indirectly detects presence of Mycobacterium tuberculosis by amplifying DNA present in the sputum by polymerase chain reaction (PCR). Amplified material can subsequently be visualized on a strip by the presence or absence of bands, much like a pregnancy test.
LIPA also detects resistance to rifampicin (a first-line drug used to treat TB), which often indicates multi-drug resistant TB.
“The benefits of LiPA include rapid diagnosis in patients who are under high suspicion for TB but have tested smear negative,” says Ben Amor.
PCR testing involves fairly significant preparations. The test is also prone to cross contamination, leading to false positives, and is prohibitively expensive for millions infected with TB, especially in impoverished areas of Africa. Despites the drawbacks, some TB experts believe that LiPA, which is currently not available in the continent, can be an effective way to detect the disease, especially MDR cases.