Tuberculosis (TB)

TB diagnostics and laboratory strengthening

The new, rapid and fully automated Xpert® MTB/RIF test is a real time cartridge-based automated DNA amplification test that will deliver a highly accurate diagnosis of the disease in less than two hours.
NHLS

A high-quality laboratory system that uses modern diagnostics is a prerequisite for early, rapid and accurate detection of TB. Lack of diagnostic capacity has been a crucial barrier preventing an effective response to the challenges of HIV-associated and drug resistant tuberculosis (TB), with only about 18% of the estimated global burden of multidrug-resistant TB (MDR-TB) and an even smaller fraction of extensively drug-resistant TB (XDR-TB) cases being detected. An expanded capacity to diagnose TB and MDR-TB is a global priority for TB control.

Care of patients with TB starts with a quality assured diagnosis, obtained by identifying Mycobacterium tuberculosis from clinical specimens and conducting DST of the organism to confirm or exclude resistance. Research on new TB diagnostic tools has been accelerated over the last few years and the diagnostic pipeline has been growing rapidly as a result. At the same time, an unprecedented effort to improve and expand TB laboratory capacity is currently being lead by WHO and the Stop TB Partnership Global Laboratory Initiative (GLI) together with the GLI network of international collaborators (http://www.stoptb.org/wg/gli).

Uptake of TB diagnostic technologies requires appropriate laboratory infrastructure and adequate policy reform at country level to enable their effective use in TB screening and diagnostic algorithms. WHO has established a structured, systematic process to rapidly review the evidence base for new TB diagnostics, ensuring that new tools meet the required performance standards. Nevertheless, even the best tools are bound to fail if all core elements of laboratory services are not addressed at the same time. These include:

  • Laboratory infrastructure, appropriate biosafety measures and maintenance
  • Equipment validation and maintenance
  • Specimen transport and referral mechanisms
  • Management of laboratory commodities and supplies
  • Laboratory information and data management systems
  • Laboratory quality management systems
  • Appropriate, adequate strategies and funding for laboratory human resource development
  • Coordination of technical assistance
  • Integration of diagnostic algorithms in laboratory strengthening plans.

Point-of-care diagnostic tests for TB are not expected before 2015; therefore, uptake of existing WHO-recommended technologies must be accelerated, which requires adequate laboratory infrastructure and clear policies at country level on their use in TB screening and diagnostic algorithms. Because of the complexity of laboratory strengthening, the involvement of expert laboratory consultants are recommended to guide the implementation process at country level.