74280-9

LOINC code 74280-9 identifies "Mitogen stimulated gamma interferon positive control spot count [#] in Blood". The count of mitogen-stimulated (e.g. phytohemagglutinin, PHA) spots (0 to >50) in a patient's T cells which serves as serves as an IFN-gamma positive control and indicates cell functionality. This term is created for, but not limited in use to, Oxford Immunotec's T-SPOT.TB assay, used to diagnose M. tuberculosis. T-SPOT.TB assay uses enzyme-linked immunospot (ELISPOT) methodology to enumerate M. tuberculosis-sensitized T cells by capturing interferon-gamma (IFN-y) in the vicinity of T cells in the patient's whole blood. In the T-SPOT test, the positive control spot count should be greater than or equal to 20 or show saturation (too many spots to count). When the spot count is <20, the result should be considered invalid unless Panel A (ESAT-6) or Panel B (CFP10) are positive or borderline.

This code measures Mitogen stimulated gamma interferon.positive control spot count in Bld. It belongs to the MICRO class in the LOINC classification.

LOINC (Logical Observation Identifiers Names and Codes) is a universal standard for identifying laboratory and clinical observations. It is maintained by the Regenstrief Institute and used worldwide for health data exchange.