The T-SPOT®.TB test is the cellular blood test that detects the immune response of T cells found in peripheral blood mononuclear cells (PBMC) that have been stimulated by Mycobacterium tuberculosis.
The immune response to infection with Mycobacterium tuberculosis is mediated predominately through T cell activation. As part of this response, T cells are sensitized to M. tuberculosis antigens. Stimulated by these antigens, the activated effector T cells, both CD4+ and CD8+, produce the cytokine interferon gamma (IFN-γ). T-SPOT.TB uses the enzyme-linked immunospot (ELISpot) methodology to enumerate M. tuberculosis-sensitized T cells by releasing interferon-gamma (IFN-γ) in the vicinity of T cells.
The T-SPOT.TB Test
- Removes background interferon gamma to maximize sensitivity
- Utilizes a standard number of PBMCs to correct for patient's immune status
- Uses TB specific antigens (ESAT-6 and CFP 10) not present in BCG and most non-tuberculosis mycobacteria to prevent cross-reactivity
Performing the T-SPOT.TB test involves the following steps using standard lab equipment: