The Relationship between Pre-Pandemic Interferon Gamma Release Assay Test Results and COVID-19 Infection: Potential Prognostic Value of Indeterminate IFN-γ Release Assay Results

Table 1

Evaluation of TBF test.

Results	Mitogen-nil value	TB-specific antigen-nil value (IU/mL)
TBF positive	≥0.5	≥0.35
TBF negative	≥0.5	<0.35
Indeterminate	<0.5	<0.35 vs nil ≤8.0