The changing landscape of diagnostic services for tuberculosis.

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.

Strengthening resistance testing for tuberculosis in India - Investment cost, throughput, and efficiency of new laboratories.

A lack of laboratory capacity for drug-resistant tuberculosis (DR-TB) testing is a major barrier to DR-TB control. To overcome this barrier, the Central Tuberculosis Division (CTD), Ministry of Health and Family Welfare (MoHFW), Government of India (GoI), and FIND India established a partnership under the National Tuberculosis Elimination Program (NTEP) to strengthen and expand tuberculosis (TB) laboratory diagnostic capabilities. This partnership has led to the establishment of 61 culture & DST laboratories, increasing the testing capacity to a capability of performing over 200,000 liquid cultures and over 170,000 molecular drug sensitivity tests annually. In this study, we assess the data on throughput, efficiency, investment cost, and the capacity of the laboratory services supported by this partnership to understand impact and inform future resource allocation. We estimated the technical efficiency using Stochastic Frontier Analysis (SFA). Our results show that the established laboratory network is operating at 69% efficiency, with the capacity to perform an additional 450,000 cultures and 180,000 first-line molecular drug-susceptibility tests by 2025. This additional capacity, together with current efforts to enhance the laboratory network, has the potential to make a significant contribution to NTEP's TB elimination target by 2025.