Role of interferon-gamma release assays in the diagnosis of pulmonary tuberculosis in patients with advanced HIV infection

Table 3 Clinical utility of T-SPOT.TB in addition to AFB smear microscopy

Test Result	Likelihood Ratio	Post-test Probability of Tuberculosis
AFB Smear Positive Patients*
T-SPOT.TB +	1.56	96%
T-SPOT.TB -	0.44	87%
AFB Smear Negative Patients^†
T-SPOT.TB +	1.48	47%
T-SPOT.TB -	0.6	26%

Abbreviations: AFB, acid-fast bacilli.
* Pre-test probability of tuberculosis = 94% (tuberculosis prevalence in AFB smear positive patients)
† Pre-test probability of tuberculosis = 37% (tuberculosis prevalence in AFB smear negative patients)

ISSN: 1471-2334