<unk>  are medical tests used in the diagnosis of some infectious diseases, especially tuberculosis.<unk>  rely on the fact that T-lymphocytes will<unk> <unk> -γ when exposed to specific antigens.  These tests are mostly developed for the field of tuberculosis diagnosis, but in theory, may be used in the diagnosis of other diseases which rely on cell-mediated immunity, e.g. cytomegalovirus and leishmaniasis.  For example, in patients with cutaneous adverse drug reactions, challenge of peripheral blood lymphocytes with the drug causing the reaction produced a positive test result for half of the drugs tested.
There are currently two<unk>  available for the diagnosis of tuberculosis:
QuantiFERON-TB Gold (licensed in US, Europe and Japan); and
T-SPOT.TB, a form of ELISPOT (licensed in Europe).
The former test quantitates the amount of gamma<unk>  produced in response to the ESAT-6 and CFP-10 antigens from Mycobacterium tuberculosis, which are distinguishable from those present in BCG and most other non-tuberculous mycobacteria.  The latter test determines the total number of individual effector T cells expressing gamma<unk> .
The indications for the test are still disputed.  It has been evaluated for the diagnosis of latent tuberculosis in HIV patients (who frequently have a negative Mantoux test).
Interferon-γ release assays
Heterophile antibody test
Enzyme linked immunosorbent assay 
Drug susceptibility testing
Mantoux test
Skin allergy testing
Direct fluorescent antibody
Molecular microbiology