Table 1.

Sensitivity & Specificity of Diagnostic Tools

Diagnostic Tool	Sensitivity	Specificity	Pros	Cons
Symptom Screening	Variable, up to 93%	Variable	Cheap, easy to implement	Large tradeoff between sensitivity and specificity, performance depends on setting
Chest X-ray	73–95%	63%	Already implemented in many centers, cheap to perform	Requires expertise to interpret, high inter-observer variability
Sputum Microscopy	60%	95%	Cheap	Time consuming, low sensitivity in HIV coinfection
Solid Media Culture	Reference standard	Reference standard	Cheap	Requires significant lab infrastructure, requires up to 8 weeks
IGRA*	69–83%	52–61%	Does not require sputum	Poor performance for active disease
Fluorescence Microscopy	70%	95%	Higher sensitivity and faster than conventional microscopy	Requires specialized equipment
Liquid Media Culture	10% more than solid media	Reference standard	Faster than solid media but still requires weeks	Specialized equipment and highly trained technicians
PCR*	10–100%	5–100%	Rapid turn-around, most are highly specific	Expensive, highly variable performance, need highly trained personnel
Xpert MTB/RIF	89%	99%	Rapid turn-around, good performance in HIV positive, moderately priced, rifampin resistance testing included	Unclear impact on mortality
LPA*	66–95%	99%	Can be performed directly on patient samples	Expensive

^*IGRA – Interferon-gamma release assay, PCR – Polymerase chain reaction, LPA - Line Probe Assay