Abstract
During the last decade there has been a dramatic change in the laboratory approach
to tuberculosis (TB) diagnosis in the developing world. This change began with the
realization that acid-fast bacillus smear microscopy alone was totally inadequate
to deal with the dual problems of human immunodeficiency virus (HIV)-associated TB
and drug-resistant TB that threaten to undermine global progress in TB control. Subsequently,
increased financial resources for TB laboratory services and the establishment of
a systematic process for endorsement of new TB diagnostic tools and approaches by
the World Health Organization (WHO) have led to rapid expansion of TB laboratory services
and the availability of several new diagnostic tests that have been introduced. These
include both commercial automated and noncommercial systems for phenotypic mycobacterial
liquid culture and drug susceptibility testing, a simple and inexpensive test for
mycobacterial species identification in culture isolates, light-emitting diode fluorescence
microscopy, and rapid molecular methods for TB case detection and the diagnosis of
drug-resistant TB. The latter methodologies that include line probe assays and an
automated cartridge-based real-time polymerase chain reaction (PCR)-based test are
being scaled up at an unprecedented pace and are truly revolutionizing the diagnosis
of drug-resistant TB. On the other hand, little progress has been made in the quest
for a true point-of-care test for TB. Fortunately, this is being addressed in several
discovery initiatives that hopefully will provide impetus for the development of rapid,
accurate TB diagnostics for the lowest level of the health system.
Keywords
tuberculosis - diagnostics - WHO endorsement
