Sepulveda W, Be C, Youlton R, Gutierrez J, Carstens E
Fetal Medicine Center, Department of Obstetrics and Gynecology, Clinica Las Condes, Santiago, Chile.
Prenat Diagn. 1999 Oct;19(10):927-9.
The haemoglobin alkaline denaturation test was routinely performed in 183 fetal blood samples obtained by cordocentesis for prenatal karyotyping by adding 0.1 ml of the blood into a glass test tube containing 5 ml of water and 0.3 ml of 10 per cent KOH as the alkali reagent. The mixture was agitated gently and read at 2 minutes, at which time it was interpreted as a pure fetal blood sample or contaminated with maternal blood according to the change in colour. In order to determine the accuracy of this test to detect maternal blood contamination, the results were compared with the number of fetal and maternal cells detected by standard cytogenetic techniques in those blood samples obtained from male fetuses (n=97). Among these samples, the haemoglobin alkaline denaturation test gave an adult haemoglobin reaction in two cases (2.1 per cent); both samples showed different degrees of maternal 46,XX cells in the metaphases examined (29 of 30 cells in one case and 2 of 31 cells in the other). Conversely, of the 95 samples which gave a fetal haemoglobin reaction, the cytogenetic analysis did not reveal any maternal cells in the metaphases analysed (median 30 cells, range 20-65). We concluded that the haemoglobin alkaline denaturation test is an accurate method for excluding clinically significant maternal blood contamination of fetal blood samples obtained for prenatal karyotyping. This simple, inexpensive technique provides immediate information and, therefore, can be safely incorporated as a bedside test for analysis during fetal blood sampling procedures.
通过脐静脉穿刺获取183份胎儿血样用于产前核型分析，常规进行血红蛋白碱性变性试验。方法是将0.1 ml血液加入含有5 ml水和0.3 ml 10%氢氧化钾（作为碱性试剂）的玻璃试管中。轻轻搅拌混合物，2分钟时读取结果，此时根据颜色变化判断为纯胎儿血样或被母体血液污染。为了确定该试验检测母体血液污染的准确性，将结果与通过标准细胞遗传学技术在从男性胎儿获取的血样（n = 97）中检测到的胎儿和母体细胞数量进行比较。在这些样本中，血红蛋白碱性变性试验在两例（2.1%）中出现成人血红蛋白反应；在检查的中期相中，两个样本均显示不同程度的母体46,XX细胞（一例30个细胞中有29个，另一例31个细胞中有2个）。相反，在95份出现胎儿血红蛋白反应的样本中，细胞遗传学分析在分析的中期相中未发现任何母体细胞（中位数30个细胞，范围20 - 65）。我们得出结论，血红蛋白碱性变性试验是排除产前核型分析所获胎儿血样中具有临床意义的母体血液污染的准确方法。这种简单、廉价的技术可提供即时信息，因此可安全地作为胎儿采血过程中床边分析试验采用。
