Reproducibility of platelet function testing

Area of Science:

• Hematology
• Clinical Pathology
• Diagnostic Testing

Background:

• Platelet aggregation and release studies are vital for diagnosing bleeding disorders.
• Establishing normal variability in these tests is essential for accurate interpretation.
• Previous data on intra-individual variability in platelet function assays is limited.

Purpose of the Study:

• To evaluate the intra-individual variation in platelet aggregation and release testing over a two-year period.
• To determine the intra-run variation for specific agonists and adenosine triphosphate (ATP) standards.
• To provide a basis for understanding the significance of abnormal results in patient testing.

Main Methods:

• Longitudinal study involving 5 subjects with 59 observations over 2 years.
• Platelet aggregation assays performed with various agonists.
• Platelet release studies, including adenosine triphosphate (ATP) release, were conducted.
• Intra-run variability was assessed for specific agonists and ATP standards.

Main Results:

• Average coefficients of variation (CV) for most agonist-induced platelet aggregations were below 17%.
• Significant variability was observed for ristocetin (1.0 mg/mL), with CVs ranging from 42% to 160%.
• Average CVs for platelet release tests exceeded 30%, with adenosine diphosphate (ADP) at 5 and 10 µM showing CVs of 56% and 42%, respectively.

Conclusions:

• Platelet aggregation and release tests exhibit considerable intra-individual variability.
• High variability, particularly with ristocetin and ADP, necessitates careful interpretation of results.
• Understanding this variability is critical for accurately diagnosing bleeding disorders and avoiding misinterpretation of patient data.