Serotonin release assay

A gold standard diagnostic test for detecting heparin-induced thrombocytopenia antibodies

Heparin-induced thrombocytopenia (HIT) is a rare but serious immune-mediated reaction to the drug heparin that can cause potentially fatal thromboembolism. While infrequent, HIT typically occurs within the first one to two weeks of a patient receiving heparin treatment, or rapidly upon heparin exposure in some patients with recent heparin therapy. Warning signs of HIT include a 50% or greater drop in platelet counts with or without thrombosis. 

Due to a number of clinical conditions that may mimic HIT and poor specificity of frontline HIT (PF4-polyanion) ELISAs, confirmation of diagnosis with a trusted functional assay is important to ensuring that only patients with HIT receive HIT-directed therapies, such as non-heparin anticoagulants.

Identifying only clinically relevant antibodies

Mayo Clinic Laboratories’ Serotonin Release Assay is the gold standard diagnostic test for detecting clinically relevant (platelet-activating) HIT antibodies. With high levels of sensitivity and specificity and timely turnaround times, our validated serotonin release assay is designed to help guide care and improve outcomes for patients suspected of having HIT.

Key testing


Nonradioactive assay helps diagnose heparin reaction [Test in focus]

Rajiv Pruthi, M.B.B.S., explains how Mayo Clinic Laboratories’ serotonin release assay achieves high sensitivity and specificity while avoiding the use of radioactive materials. Serotonin release testing is an important tool in the diagnosis of heparin induced thrombocytopenia, or HIT, which can have devastating consequences for patients.

Learn more about how to order these tests at your institution.

Additional resources