Association between presence of a platelet function defect and the ISTH bleeding assessment tool score. Ninety-fifth percentile (score of 4) calculated from healthy volunteers and represented by horizontal dotted line. The line represents the median and the whiskers represent the interquartile range. (A) Presence and absence of a platelet defect defined by lumi-aggregometry. (B) Presence and absence of a platelet defect defined by the Optimul assay.