Table 2.

Interpretation of the T-Cell Activation Biomarker Test Results

M.tb-Specific Response Definition			Responder Definition	Recent M.tb Infection or TB Definition
IFN-γ+ TNF+ T Cells ESAT-6/CFP-10 vs. UNS (Fisher Exact Test)	IFN-γ+ TNF+ T Cells PHA vs. UNS (Fisher Exact Test)	Interpretation	IFN-γ+ TNF+ T Cells ESAT-6/CFP-10 over UNS (Ratio)	Δ HLA-DR MFI (IFN-γ+ TNF+)  − (Total T Cells)	Interpretation
P ≤ 0.01	Any	M.tb infection likely	Threefold or greater	− (<734)	Persistent M.tb infection likely
				+ (≥734)	Recent M.tb infection or TB likely
			Less than threefold	N/A	N/A
P > 0.01	P < 0.01	M.tb infection unlikely	N/A	N/A	N/A
P > 0.01	P > 0.01	Indeterminate	N/A	N/A	N/A

Definition of abbreviations: MFI = median fluorescent intensity; M.tb = Mycobacterium tuberculosis; N/A = not applicable; PHA = phytohemagglutinin positive control; TB = tuberculosis; UNS = unstimulated control.