The process of VWD diagnosis (or, in a wider context, the evaluation of a possible mild bleeding disorder) may start either from the clinical assessment of a subject referred for bleeding symptoms (i.e., a symptom-driven diagnosis) or from the laboratory study of an abnormal laboratory test (i.e., a laboratory-driven diagnosis, such as in a preoperative screening).10 The laboratory-driven diagnosis is often unsatisfactory, because of the poor correlation between plasma VWF levels and severity of bleeding symptoms, resulting in a scarce predictive value of VWF measurement. This evidence concerns the gene VWF and hemorrhagic disease.