Tuberculosis, a disease that many believed to be conquered in the early twentieth century, is back with a vengeance. Even though the most common strain is 100 percent treatable, tuberculosis (TB) continues to kill over two million people each year. Doctors blame this high mortality rate on the increased prevalence of multidrug-resistant tuberculosis (MDRTB), which is unresponsive to traditional antibiotics. Developing countries lack both affordable and accurate TB testing, hindering proper diagnosis and contributing to the spread of MDRTB. But now, thanks to a simple new test, MDRTB may no longer elude diagnosis in the developing world. Known as the microscopic-observation drug-susceptibility (MODS) test, this technology is more cost effective and accurate than current TB tests, as well as more sensitive to drug-resistant TB strains.

Currently, the World Health Organization (WHO) advocates sputum smear microscopy for TB diagnosis in developing and urban settings. In this test, a technician smears sputum -- a mixture of respiratory discharge and saliva generated by a deep cough -- on a glass slide. The slide is then observed under a microscope to identify the coils and tangles characteristic of Mycobacterium tuberculosis, the organism that causes TB infection in one-third of the world?s population. TB-positive samples are cultured for three weeks, followed by up to six weeks of drug susceptibility testing. Unfortunately, this diagnostic tool is only 50 percent accurate, allowing many cases of MDRTB to remain undiagnosed. Furthermore, during the many weeks of testing, a patient may sicken or transmit the TB infection to others, especially in overcrowded urban areas and cohesive rural communities. Sputum smear microscopy is also particularly unsuited to developing regions since it requires detailed laboratory analysis and specialized facilities, which are rarely available.

Several experts criticize the WHO's recommendation of sputum-smear TB testing in underdeveloped countries. One critic, Dr. David Moore of the Imperial College London, is a member of the international team of researchers that developed the MODS test in response to the failings of previous TB diagnostics. He believes that "the standard of care in testing for TB and its multidrug-resistant strains in developing countries is set way below that in industrialized nations...sputum smear microscopy alone, the current diagnostic tool integral to the WHO's strategy for global TB control and used to diagnose the vast majority of TB patients across the globe, is no longer adequate."