Evaluation platelet function by flow cytometry

Introduction: The laboratory diagnostics of (inherited) platelet function disorders mainly comprises aggregation and secretion assays, but is not reliable enough for diagnosing mild platelet function disorders with low platelet count. For diagnosis of patients with mild bleeding disorders, analysis of expression of platelet surface glycoproteins is essential.Methods: Flow cytometry enables studies of a number of different aspects of platelet function in response to a variety of platelet agonists and with just a few microliters of blood provide additional value during the diagnostic work-up of platelet function disorders. Platelet function can be investigated in patients with thrombocytopenia. As the surface expression of many of platelet receptors change upon platelet activation, we can use it for evaluation function of platelet. The most common choice for blood anticoagulation is still sodium citrate (3.2 or 3.8). In this protocol platelets first activated by addition of one or more platelet agonists (thrombin, PAR1-AP and etc.) to the diluted blood samples, after that markers include of GPIIb (CD41, integrin αIIb), GPIIIa (CD61, integrin β3), GPIbα (CD42b), and GPIX (CD42a) as a first step and GPIa/IIa (α2β1), GPIV, and GPVI as a second step analysed by flow cytometry. This test should not be performed on activated platelets.Results: Results from the analysis can be expressed either as the percentage of cells being positive for the marker or the median fluorescence intensity of the total platelet population.Conclusion: The increasingly challenging analysis needs to be dealt with before this can become reality. Some limitations have to be considered like standardization, validation, measure platelet function under shear stress and can only end-point measurements. These analyses can be implemented in clinical practice to improve the diagnostic armamentarium for patients with suspected platelet disorders that has dangerous complication such as brain haemorrhage.

Keywords:

platelet , flow cytometry , platelet function disorders