Instrumentation Laboratory has received FDA clearance for the HemosIL HIT-Ab(PF4-H) assay for use on ACL TOP® Family Hemostasis Testing Systems. The first, fully automated, on-demand assay for Heparin-Induced Thrombocytopenia (HIT) on a hemostasis testing system, HemosIL HIT-Ab(PF4-H) detects antibodies associated with HIT. HIT is a severe immunologic adverse reaction to a heparin complex that paradoxically causes blood clots to form, leading to venous and/or arterial thrombosis, and can be fatal. Diagnosis of HIT is key to positive patient outcomes and may prompt initiation of alternative anticoagulants. Unlike existing manual processes, HemosIL HIT-Ab(PF4-H) is a liquid, ready-to-use immunoassay that delivers results in minutes—on-demand, 24/7—allowing clinicians to make timely, well-informed therapeutic decisions, essential in critical scenarios. Management of HIT involves cessation of heparin therapy and initiation of expensive alternative anticoagulants. Delays in diagnosis caused by prolonged test turnaround time can lead to speculative treatment, increasing bleeding risk for the patient and increasing drug costs, if replacement anticoagulant therapy is used unnecessarily. Conversely, if patients with HIT remain on heparin while awaiting laboratory confirmation of diagnosis, they may develop more serious complications leading to increased morbidity and mortality. Therefore, the availability of on-demand HIT antibody testing plays a critical role in better managing HIT, providing results when treatment decisions are needed, and ultimately minimizing patient risk and reducing costs.