How the T-SPOT.TB test works

1 small tube. 1 million ways to find the truth.2

The immune response to infection with Mycobacterium tuberculosis (MTB) is mediated predominantly through T cell activation. As part of this response, T cells are sensitised to MTB antigens and the activated effector T cells, both CD4 and CD8, produce the cytokine interferon-gamma when stimulated by these antigens. The T-SPOT.TB test uses T-SPOT technology, a modified version of the enzyme-linked immunospot (ELISPOT) methodology to enumerate M. tuberculosis-sensitised T cells by capturing interferon-gamma in the vicinity of CD4 and CD8 T cells from which it was secreted.2

When your test looks for signs of TB infection using T cells, it matters how many T cells you include. The T-SPOT.TB test, unlike other tests, uses the same number each time. And it’s a big number: 250,000 cells per well, four wells per test.2 That’s a million witnesses to infection – and a moment of truth for TB.

The principles of the T-SPOT.TB test:

T-SPOT.TB test technology

Step 1

A blood specimen is collected using routine phlebotomy and a standard blood collection tube from which a subset of white blood cells, known as peripheral blood mononuclear cells (PBMC), are isolated. The cells are washed, counted and normalised to create a standard cell suspension.

T-SPOT.TB test technology

Step 2

A standard number of cells are added into specially designed plates and stimulated with TB-specific antigens, ESAT-6 and CFP10. Cells responding to these antigens release interferon-gamma.

Step 3

Interferon-gamma antibodies are used to directly capture interferon-gamma as it is released by the cells. A secondary enzyme labeled antibody is added and binds to the captured interferon-gamma.

Step 4

A detection reagent is added and reacts with the enzyme labeled antibody. This reaction produces spots, which are a footprint of where the interferon-gamma was released. Spots are then enumerated.

All of the above can now be automated. Improve your workflow efficiency, reduce your hands-on time and simplify your SOPs with modular automation solutions to fit your needs.

Liquid handling steps of the plate development process can be automated
Each result should be individually validated before reporting

Learn more about the T-SPOT.TB test