The performance of the platelet function analyzer is insufficient to reliably diagnose an increased bleeding tendency in children and adult patients

Despite widespread use of the Platelet Function Analyzer-100 closure time (PFA) as alternative to the bleeding time (BT) for the analysis of primary hemostasis defects, the predictive value is highly variable. This may partly be due to the lack of larger studies, especially in children. We assessed the sensitivity and specificity of the PFA and BT in a large number of patients with increased bleeding tendency due to von Willebrand disease (vWD) and other platelet function disorders (PFD). In addition, we analysed the effect of desmopressin on the PFA in these patients. Methods: PFA and/or BT were measured in a total of 1027 patients (484 children) with increased bleeding tendency. The final diagnosis was ascertained by measurement of specific platelet function tests or clotting factor levels. We also analysed the effect of treatment with 0.3 ig/kg desmopressin on the PFA. Results: Sensitivity and specificity of the PFA were moderate, with no clear differences between children and adults with vWD (Table). The detection of PFD with the PFA was better in children than in adults. The sensitivity of the BT was comparable to the PFA, but the specificity in children was very low. In 54 patients, desmopressin treatment significantly shortened PFA except for one patient with M. Glanzmann and one with vWD. Table represented. Conclusion: Based on this large cohort, the predictive value of the PFA and BT for PFD and vWD in children and adults with increased bleeding tendency is insufficient. The BT had a comparable sensitivity, whereas its specificity was lower than that for PFA, especially in children. PFA seems suitable for measuring the effect of desmopressin