At the central level (Level III), testing requiring highly advanced skills, infrastructure and biosafety precautions is offered. An important expectation at this level is to provide testing to resolve discord results, troubleshooting, training support to other levels, QA and monitoring, and surveillance.
- FL-LPA, SL-LPA and NGS are all applicable at this level. The moderate complexity automated NAATs with high throughput could also be considered at this level. In addition, establishing capacity for sequencing is becoming increasingly important. The new class of high complexity reverse hybridization NAAT for PZA is suited to this level. It is the first rapid molecular test for resistance to this important drug and can make use of existing LPA infrastructure.
- Culture and phenotypic DST using solid or liquid media should be available at this level. At a minimum, phenotypic DST for the new and repurposed drugs should be available.
AFB: acid-fast bacilli; DST: drug susceptibility testing; FL: first-line; LAMP: loop-mediated isothermal amplification; LF-LAM: lateral flow lipoarabinomannan assay; LPA: line-probe assay; NAAT: nucleic acid amplification test; SL: second-line; TB: tuberculosis.