Platelets are essential blood elements to maintain hemostasis. Quantitative or qualitative defects can be responsible of hemorrhagic (platelet disorders) or thrombotic (heparin induced thrombocytopenia [HIT]) troubles. Diagnosis of these pathologies is sometimes urgent and consists in delicate platelet functional assays that are mostly made in expert centers. These platelets functional assays measure platelets activation and/or aggregation in response to diverse inductors and may lack sensitivity. The investigators would like to propose a new diagnostic tool with the use of imaging flow cytometry which provides much more information than classic cytometer on cell morphology thanks to images collected by the optical channel of the ImageStream cytometer. The use of this cytometer offers an innovative approach.

This study is a monocentric prospective and non-interventional study. The investigators will analyze patient samples with the ImageStream cytometer and reference laboratory tests (light transmission aggregometry and serotonin release assay) in parallel and compare results from the different techniques. This new diagnostic technique will demonstrate a non-inferiority diagnosis compared to reference tests and maybe a better sensibility.

Inclusion Criteria:

• male or female patient for whom a blood test was prescribed in a context of diagnosis of platelet dysfunction or HIT

Exclusion Criteria:

• minor patients
• patients who have opposed the use of their personal data for research work.

Male or female patient for whom a blood test was prescribed in a context of diagnosis of platelet dysfunction or HIT.