Confirmatory assay used in the evaluation of heparin-induced thrombocytopenia (HIT).

Gold serum separator (SST) tube

Immediately following collection, thoroughly mix sample by gently inverting 5 times

1. Allow sample to clot for a minimum of 30 minutes
2. Spin within two (2) hours of sample collection
3. Transfer serum to a Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp), labelled as serum
4. Freeze

Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp)

Red serum vial/tube, 5 mL

1. Allow sample to clot
2. Spin 
3. Transfer serum to a Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp), labelled as serum, within two (2) hours of sample collection
4. Freeze

Frozen

Room temperature specimen received; grossly hemolyzed, icteric, and lipemic samples

The SRA employs washed donor platelets and detects their activation by measuring the release of endogenous serotonin induced by addition of patient serum. The serotonin levels are measured by a highly sensitive liquid chromatography/ tandem mass spectroscopy method. Therapeutic levels of heparin included in the assay mix allow for the formation of PF4/heparin complexes on the donor platelet surface to provide an antigen target for the HIT antibodies. The specificity of the assay is increased by assessing the inhibition of platelet activation by adding heparin in excess, thus proving the heparin dependency of the serotonin release.

An interpretive report will be provided