The first stage involved demonstrating the agent responsible for this autoimmune reaction (known as allergy to heparin), namely PF4, a platelet cytokine that forms a complex with heparin resulting in sensitisation in certain patients.
Stago subsequently developed an immunological test to detect the corresponding antibodies, thus providing laboratory staff and clinicians alike with reliable tests: Asserachrom? HPIA and, more recently, Asserachrom? HPIA IgG.
The risk of HIT is greater with unfractionated heparin (UFH ?3%) than with low molecular-weight heparin (LMWH ?1%). A retrospective American study shows that of 12 million patients treated annually, 1 to 5% present HIT, with thrombosis occurring as a complication in half of these patients and resulting in death in 20 to 30% of cases (i.e. up to 90 000 deaths/year) - Levine RL Chest 2005;127:1488-1490 .
Given the high number of patients receiving heparin on a daily basis, HIT is a serious public health concern that is now easier to diagnose accurately thanks to these laboratory tests in particular.