|The impact of new diagnostic tools for TB on the public health system|
|Initial versus new tool||Use||Staffing impact/advantage||Patient impact/advantage||Laboratory advantage||Reading||Public health impact of second tool|
|TST versus gamma interferon release||Latent TB||Qualified nurse to apply and read TST vs phlebotomist||Two versus one visit||Low versus higher specificity||Moderately standardized versus more precise cut-off||Fewer referrals due to more specific diagnosis LTBI.|
|Solid versus liquid culture||Active TB||Unchanged||Improved sensitivity||Higher sensitivity for detection (but offset if higher contamination)||Non-automated versus automated cut-off||Identification of all TB cases reduce transmission|
|Smear* versus Xpert® MTB/RIF system or LPA||Active TB||Arguably less trained staff needed||Greater sensitivity; but no indicator of infectivity||Low versus high sensitivity and specificity||Variable versus cut-off||Fewer false positive results|
|Due to inactivation lower risk of staff infection|
|Smear *versus Xpert® MTB/RIF system or LPA, for example, GenoType® MDRTBPlus||Drug resistance||Less qualified personnel initially for interpretation||Short turnaround time for marker antibiotic||No versus one key marker antibiotic (rifampicin) and also isoniazid for LPA||Variable versus exact cut-off||Immediate availability of marker antibiotic results; poor PPV in low prevalence areas|
|Phenotypic versus GenoType® MTBDRsl line probe assay (LPA) for FQ, injectable agents||Drug resistance||Unchanged for qualification of staff, reduced risk for staff infection||In areas with high MDR rates shorter turnaround for XDR-TB detection||Earlier XDR-TB screen and set-up of other drug testing for treatment||Simpler cut-off; limited drug range||Immediate preliminary screening for MDR- and XDR-TB and aid planning contact investigation|
* “Smear” means the microscopic examination of sputum.
LPA, line prove assay; PPV, positive predictive value; MDR-TB, Multidrug-resistant tuberculosis; TST, tuberculin skin testing; XDR-TB, extensively drug-resistant TB; LTBI, Latent TB infection.
Drobniewski et al.
Drobniewski et al. BMC Medicine 2013 11:190 doi:10.1186/1741-7015-11-190