问题5:疑似1型VWD的患者初始VWD筛查异常[VWF∶Ag和(或)VWF血小板依赖性活性降低]时,能够确诊的VWF∶Ag和(或)VWF血小板依赖性活性结果的阈值是<0.3 IU/ml还是<0.5 IU/ml? The gene discussed is VWF; the disease is von Willebrand disease (hereditary or acquired).