Service developments

Introduction of HITAlert platelet activation assay for investigation of heparin induced thrombocytopenia (HIT) from 1 April 2021

The PF4 / heparin antibody detection by ELISA is a useful tool for diagnosis of HIT, however a functional assay would determine if the patient’s serum is capable of activating platelets.

A functional assay is advantageous in the following circumstances:

  • Confirmation where a high 4T score strongly suggest HIT but the ELISA assay is negative or where a positive non-inhibitable result is obtained with the ELISA assay
  • Functional assay detecting only those antibodies capable of activating platelets
  • Able to detect antibodies reacting with all heparin complexes (IL-8, NAP-2) not only heparin / platelet factor 4 complex
  • HITAlert has a high negative predictive value (99.1%) and high positive predictive value (88.2%) toward final clinical diagnosis 
  • Reduction in the requirement for pre-procedure conditioning, for example plasmapheresis

Please refer to the BSH guidelines for information on the diagnosis and management of heparin induced thrombocytopenia.

The assay will only be performed subsequent to an initial ELISA test and after discussion with the H&I laboratory. Please refer to section 5.8, page 38 of the user guide for information.

Contact details

NHSBTHIFilton.Enquiries@nhsbt.nhs.uk
0117 921 7532 / 7531