Requires prior approval from Haematologists - contact via LabLink/Hospital Operator.
0.5ml (minimum) frozen serum
- Haemolysed and lipaemic samples cannot be used.
Results are reported as Positive or Negative.
Note: This test is performed 0800 - 1600 Monday - Friday only .
ELISA - microtitre plate wells are coated with Heparin-PF4 antigen, which captures the antibody in patient's serum if present. A second antibody conjugated to horse radish peroxidase is added and binds to captured Hep-PF4 antibody. Addition of TMB/H2O2 causes colour development in proportion to the amount of captured Hep-PF4 antibody.
At LabPlus this test is performed as part of our HIT testing algorithm. Heparin-PF4 ELISA testing is performed as a follow-up test on all samples with positive HITS Screen. A small percentage of patients receiving Heparin/LMWH may develop antibodies to a Heparin-PF4 antigen, leading to platelet activation, thrombocytopaenia with or without thrombotic events. A negative result has a high predictive value for HIT.
A thrombocytopenic thrombotic syndrome has been described in a proportion of patients exposed to COVID19 vaccinations (AstraZeneca and Janssen). Antibodies against platelet antigens (PF4) post vaccination have been detected with some similarity to Heparin induced thrombocytopenia (HIT)but with a distinct profile on immune and functional testing .This immune thrombosis syndrome is currently being called several names :
"VIPIT": Vaccine induced Prothrombotic Immune thrombocytopenia
"TTS": Thrombosis with thrombocytopenia syndrome
"VITT": Vaccine induced immune thrombotic thrombocytopenia.
Antibodies against PF4 or PF4/Polyanion complexes have been detected using ELISA methods, but no other platforms used for HIT testing.
For further information contact the Haematology laboratory (Ext 22067) or:
| Dr Nicola Eaddy | Ext 22005 | |
| Dr Peter Bradbeer | Ext 22062 | |
| Dr Anna Ruskova | Ext 22137 | |
| Dr Nikhil Rabade | Ext 22071 | |
Minimum 0.5ml frozen serum, to arrive frozen.