Description

There are reports of vascular injury and platelet changes causing vascular- induced thrombotic thrombocytopenia(VITT). This testing typically comprises platelet counts, D‐dimer, fibrinogen, and various immunological and functional assays for platelet factor 4 (PF4) antibodies. In suspected VITT, there is a generally highly elevated level of D‐dimer, thrombocytopenia, and PF4 antibodies can be identified by ELISA‐based assays, but not by other immunological assays typically positive in HITT. In addition, in some functional platelet activation assays, standard doses of heparin have been identified to inhibit activation in suspected VITT, but they tend to augment activation in HITT. Conversely, it is also important to not over‐diagnose VITT, given that not all cases of thrombosis post vaccination will have an immune basis and not all PF4‐ELISA positive patients will be VITT.

The following test are included:

Anti-PF4

Complete Blood Count

D-dimer

Fibrinogen

Fasting not required.

Additional information about each test is listed below:

Antibodies against the chemokine platelet factor 4 (PF4) occur often, but only those that activate platelets induce severe prothrombotic disorders with associated thrombocytopenia. 

A Complete Blood Count (CBC) will evaluate the current platelet count as well as the white and red blood cell count.

Elevated D-dimer could cause the formation of pulmonary microthrombus, deep venous thrombosis, and disseminated intravascular coagulopathy

A fibrinogen panel is a group of tests that measure fibrinogen levels in the blood and evaluate its function. Fibrinogen is a protein produced in the liver that helps blood clot.