Anti-PF4 testing for vaccine-induced immune thrombocytopenia and thrombosis (VITT): Results from a NEQAS, ECAT and SSC collaborative exercise in 385 centers worldwide.
J Thromb Haemost
; 20(8): 1875-1879, 2022 08.
Article
in English
| MEDLINE | ID: covidwho-1891645
ABSTRACT
BACKGROUND:
Vaccine-induced immune thrombocytopenia and thrombosis (VITT) following the administration of the AstraZeneca (AZ) ChAdOx1 nCOV-19 vaccine is a well recognized clinical phenomenon. The associated clinical and laboratory features have included thrombosis at unusual sites, thrombocytopenia, raised D-dimer levels and positivity for immunoglobulin G (IgG) anti-platelet factor 4 (PF4) antibodies.OBJECTIVES:
A collaborative external quality assessment (EQA) exercise was carried out by distributing five lyophilized samples from subjects with VITT and one from a healthy subject to 500 centers performing heparin-induced thrombocytopenia (HIT) testing.METHODS:
Participating centers employed their locally validated testing methods for HIT assays, with some participants additionally reporting results for VITT modified assays.RESULTS:
A total of 385 centers returned results for anti-PF4 immunoassay and functional assays. The ELISA assays used in the detection of anti-PF4 antibodies for the samples distributed had superior sensitivities compared with both the functional assays and the non-ELISA methods.CONCLUSION:
ELISA-based methods to detect anti PF4 antibodies have a greater sensitivity in confirmation of VITT compared with functional assays regardless of whether such functional assays were modified to be specific for VITT. Rapid immunoassays should not be employed to detect VITT antibodies.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Thrombocytopenia
/
Thrombosis
/
Platelet Factor 4
/
Purpura, Thrombocytopenic, Idiopathic
/
ChAdOx1 nCoV-19
Type of study:
Diagnostic study
/
Prognostic study
Topics:
Vaccines
Limits:
Humans
Language:
English
Journal:
J Thromb Haemost
Journal subject:
Hematology
Year:
2022
Document Type:
Article
Affiliation country:
Jth.15766
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