A new molecular test for tuberculosis doubled detection of the disease over the standard point–of–care test among HIV–infected adults in Malawi and halved death rates for those with advanced HIV, according to new research from Richard Chaisson, MD, director of the Center for Tuberculosis Research at the Johns Hopkins University School of Medicine, Lucky G. Ngwira of the Malawi Liverpool Wellcome Trust Clinical Research Programme, and colleagues from the Johns Hopkins University School of Medicine and Johns Hopkins Bloomberg School of Public Health.

Ngwira presented on the outcomes of a cluster–randomized trial screening for tuberculosis, comparing the molecular test, called Xpert MTB/RIF to standard testing for disease using sputum smear microscopy at 9th International AIDS Conference on HIV Science.

Sputum smear microscopy, though less costly than Xpert, has a lower level of diagnostic sensitivity, putting HIV–infected individuals at risk of a missed diagnosis of tuberculosis. A research team led by Chaisson studied 1,842 adult Malawians recently diagnosed with HIV infection and compared the new, rapid molecular Xpert MTB/RIF assay, performed in the clinic, to the standard fluorescent microscopy. Screening for tuberculosis with Xpert resulted in twice the rate of diagnoses and a 50 percent reduction in mortality for patients with advanced HIV compared to microscopy.

The study, supported by the National Institute of Allergy and Infectious Diseases, was conducted at 12 clinics in a rural district of Malawi with extremely limited resources. The researchers note that providing a sensitive point–of–care diagnosis with a molecular test in settings without access to sophisticated laboratories could save lives in many high–burden countries.