Abstract：
Beta-thalassaemia is characterized by a decrease (β(+)) or absence (β(0)) in the synthesis of β-globin chains of human haemoglobin. The heterozygous state for β(+) or β(0) result in β-thalassaemia trait in which the hallmark is the presence of an elevated level of Haemoglobin (Hb) A(2) (α(2)δ(2)). In the past, the traditional methods such as cellulose acetate electrophoresis with elution and microcolumn chromatrography have been the techniques used by the majority of the laboratories in Malaysia for the estimation of (Hb) A(2) levels. The recommended method currently is high performance liquid chromatography which has only been introduced in a few laboratories in the country.
OBJECTIVE: To determine the cut-off level for (Hb) A(2) when estimated by high performance liquid chromatography (HPLC) in the diagnosis of classical beta-thalassaemia trait, a condition in the homozygous state that results in beta-thalassaemia major and red blood cell transfusion dependency.
RESULTS: High performance liquid chromatography (HPLC) as a method for the measurement of (Hb) A(2) was rapid, and technically easy. A cut-off level of (Hb) A(2) >4.0 % predict the majority of carriers of classical beta-thalassaemia.
CONCLUSIONS: A full blood count (FBC), together with red blood cell indices generated on an automated blood counter in conjunction with the measurement of Hb A(2) on the VARIANT-BioRad, an automated HPLC machine and the beta-thal short program is an appropriate approach for the screening and presumptive identification of carriers of classical beta-thalassaemia prior to DNA studies for definitive diagnosis. In carriers for classical beta-thalassaemia, the MCV and MCH are <75 fl and <27 pg respectively with a Hb A(2) cut-off level > 4.0% [range 5.9 (4.5-8.1)] on the VARIANT-BioRad.
OBJECTIVE: To determine the cut-off level for (Hb) A(2) when estimated by high performance liquid chromatography (HPLC) in the diagnosis of classical beta-thalassaemia trait, a condition in the homozygous state that results in beta-thalassaemia major and red blood cell transfusion dependency.
RESULTS: High performance liquid chromatography (HPLC) as a method for the measurement of (Hb) A(2) was rapid, and technically easy. A cut-off level of (Hb) A(2) >4.0 % predict the majority of carriers of classical beta-thalassaemia.
CONCLUSIONS: A full blood count (FBC), together with red blood cell indices generated on an automated blood counter in conjunction with the measurement of Hb A(2) on the VARIANT-BioRad, an automated HPLC machine and the beta-thal short program is an appropriate approach for the screening and presumptive identification of carriers of classical beta-thalassaemia prior to DNA studies for definitive diagnosis. In carriers for classical beta-thalassaemia, the MCV and MCH are <75 fl and <27 pg respectively with a Hb A(2) cut-off level > 4.0% [range 5.9 (4.5-8.1)] on the VARIANT-BioRad.
摘要：
β-地中海贫血的特征是人血红蛋白的β-珠蛋白链的合成减少（β（））或不存在（β（0））。β(+)或β(0)的杂合状态导致β-地中海贫血性状,其中标志是存在升高水平的血红蛋白(Hb)A(2)(α(2)δ(2))。在过去,传统的方法，如醋酸纤维素电泳与洗脱和微柱色谱已被马来西亚的大多数实验室用于估计（Hb）A（2）水平的技术。目前推荐的方法是高效液相色谱法，仅在该国的一些实验室中引入。
目的：为了确定通过高效液相色谱法（HPLC）估算的（Hb）A（2）在经典β-地中海贫血特征诊断中的截止水平，一种纯合子状态的疾病，导致β-地中海贫血和红细胞输血依赖。
结果：高效液相色谱（HPLC）作为测量（Hb）A（2）的方法是快速的，技术上容易。（Hb）A（2）>4.0％的截止水平预测了大多数典型β-地中海贫血的携带者。
结论：全血计数（FBC），连同在自动血液计数器上产生的红细胞指数，以及在VARIANT-BioRad上测量的HbA（2），在进行DNA研究以明确诊断之前,自动HPLC机器和β-thal短程序是筛选和推定鉴定经典β-地中海贫血携带者的适当方法.在典型β-地中海贫血的携带者中，MCV和MCH分别<75fl和<27pg,在VARIANT-BioRad上HbA(2)截止水平>4.0%[范围5.9(4.5-8.1)]。
目的：为了确定通过高效液相色谱法（HPLC）估算的（Hb）A（2）在经典β-地中海贫血特征诊断中的截止水平，一种纯合子状态的疾病，导致β-地中海贫血和红细胞输血依赖。
结果：高效液相色谱（HPLC）作为测量（Hb）A（2）的方法是快速的，技术上容易。（Hb）A（2）>4.0％的截止水平预测了大多数典型β-地中海贫血的携带者。
结论：全血计数（FBC），连同在自动血液计数器上产生的红细胞指数，以及在VARIANT-BioRad上测量的HbA（2），在进行DNA研究以明确诊断之前,自动HPLC机器和β-thal短程序是筛选和推定鉴定经典β-地中海贫血携带者的适当方法.在典型β-地中海贫血的携带者中，MCV和MCH分别<75fl和<27pg,在VARIANT-BioRad上HbA(2)截止水平>4.0%[范围5.9(4.5-8.1)]。
