Abstract：
BACKGROUND: Diagnosing hemophilia B (HB) carrier status is important to manage bleeding in carriers and to prevent bleeding in potential offspring. Without a family history of hemophilia, diagnosing HB carrier status is challenging. Genetic testing is the gold-standard, however it is reserved for individuals with a high suspicion of carrier status.
OBJECTIVE: To describe the distribution of activated partial thromboplastin time (aPTT) and factor IX coagulant (FIX:C) levels in HB carriers and assess the ratio of FIX:C to other Vitamin K dependent factors (FII:C, FVII:C, FX:C) as an indicator of HB carrier status.
METHODS: In this retrospective, single-centre cohort study, subjects were included if they were obligate or genetically proven HB carriers. Distributions of aPTT and FIX:C were described and the relationship between FIX:C levels in carriers and severity of familial HB was analysed. Ratios of FIX:C to FII:C, FVII:C, FX:C were calculated.
RESULTS: Seventy-two female HB carriers (median age: 34 years; IQR 24-43) were included. Median aPTT and FIX:C levels were 33.0 s [IQR 30.0-37.0] and 57 IU/dL [IQR 43-74]. Fifteen carriers (21%) had mild HB (FIX:C levels of 10-40 IU/dL). FIX:C levels trended higher in carriers of mild HB versus carriers of moderate/severe HB. In six carriers, the median ratio of FIX:C to other Vitamin K dependent factors was 0.44, with 92% of ratios being ≤ 0.75.
CONCLUSIONS: aPTT and FIX:C levels were unreliable in diagnosing HB carrier status. A low ratio of FIX:C to other Vitamin K dependent factors may be a useful marker of HB carrier status.
OBJECTIVE: To describe the distribution of activated partial thromboplastin time (aPTT) and factor IX coagulant (FIX:C) levels in HB carriers and assess the ratio of FIX:C to other Vitamin K dependent factors (FII:C, FVII:C, FX:C) as an indicator of HB carrier status.
METHODS: In this retrospective, single-centre cohort study, subjects were included if they were obligate or genetically proven HB carriers. Distributions of aPTT and FIX:C were described and the relationship between FIX:C levels in carriers and severity of familial HB was analysed. Ratios of FIX:C to FII:C, FVII:C, FX:C were calculated.
RESULTS: Seventy-two female HB carriers (median age: 34 years; IQR 24-43) were included. Median aPTT and FIX:C levels were 33.0 s [IQR 30.0-37.0] and 57 IU/dL [IQR 43-74]. Fifteen carriers (21%) had mild HB (FIX:C levels of 10-40 IU/dL). FIX:C levels trended higher in carriers of mild HB versus carriers of moderate/severe HB. In six carriers, the median ratio of FIX:C to other Vitamin K dependent factors was 0.44, with 92% of ratios being ≤ 0.75.
CONCLUSIONS: aPTT and FIX:C levels were unreliable in diagnosing HB carrier status. A low ratio of FIX:C to other Vitamin K dependent factors may be a useful marker of HB carrier status.
摘要：
背景：诊断B型血友病（HB）携带者状态对于控制携带者的出血和预防潜在后代的出血非常重要。没有血友病家族史,诊断HB携带者状态具有挑战性。基因检测是黄金标准,然而，它是为高度怀疑承运人身份的个人保留的。
目的：描述活化部分凝血活酶时间（aPTT）和因子IX促凝剂（FIX：C）水平在HB携带者中的分布，并评估FIX：C与其他维生素K依赖性因子（FII：C，FVII:C,FX：C）作为HB承运人状态的指标。
方法：在本回顾性研究中，单中心队列研究，如果受试者是专性或经遗传证实的HB携带者，则将其包括在内。描述了aPTT和FIX：C的分布，并分析了携带者中FIX：C水平与家族性HB严重程度之间的关系。FIX：C与FII：C的比率，FVII:C,计算FX:C。
结果：纳入72名女性HB携带者（中位年龄：34岁；IQR24-43）。中位数aPTT和FIX：C水平分别为33.0s[IQR30.0-37.0]和57IU/dL[IQR43-74]。15个携带者(21%)具有轻度HB(FIX:10-40IU/dL的C水平)。修复:与中度/重度HB的携带者相比,轻度HB的携带者中的C水平趋于更高。在六艘航母中，FIX:C与其他维生素K依赖因子的中位比值为0.44,92%的比值≤0.75.
结论：aPTT和FIX：C水平在诊断HB携带者状态方面不可靠。FIX：C与其他维生素K依赖性因子的低比率可能是HB携带者状态的有用标记。
目的：描述活化部分凝血活酶时间（aPTT）和因子IX促凝剂（FIX：C）水平在HB携带者中的分布，并评估FIX：C与其他维生素K依赖性因子（FII：C，FVII:C,FX：C）作为HB承运人状态的指标。
方法：在本回顾性研究中，单中心队列研究，如果受试者是专性或经遗传证实的HB携带者，则将其包括在内。描述了aPTT和FIX：C的分布，并分析了携带者中FIX：C水平与家族性HB严重程度之间的关系。FIX：C与FII：C的比率，FVII:C,计算FX:C。
结果：纳入72名女性HB携带者（中位年龄：34岁；IQR24-43）。中位数aPTT和FIX：C水平分别为33.0s[IQR30.0-37.0]和57IU/dL[IQR43-74]。15个携带者(21%)具有轻度HB(FIX:10-40IU/dL的C水平)。修复:与中度/重度HB的携带者相比,轻度HB的携带者中的C水平趋于更高。在六艘航母中，FIX:C与其他维生素K依赖因子的中位比值为0.44,92%的比值≤0.75.
结论：aPTT和FIX：C水平在诊断HB携带者状态方面不可靠。FIX：C与其他维生素K依赖性因子的低比率可能是HB携带者状态的有用标记。
