Torres Eneida, Baloy Arlenys, Frómeta Amarilys, Fernández Lianny
Laboratorio de Pesquisaje Neonatal, Centro de Inmunoensayo, Ciudad de La Habana, Cuba.
Biomedica. 2002 Mar;22(1):22-9.
Neonatal screening programs for metabolic disorders are recommended especially for phenylketonuria and congenital hypothyroidism. The present study was designed to adapt, develop and evaluate a SUMA method for total galactose (Gal) and phenylalanine (Phe) measurement on filter paper blood specimens. A single 5 mm disk with blood was deproteinized with methanol-acetone and eluted with distilled water. Ten microliters of the extract was transferred to one well of a ultramicroELISA plate, and the reaction solution was added to determine Phe level. The remaining extract was used for the GAL determinations. The method showed good linearity in a 0-50 mg/dl concentration range for Phe and 0-60 mg/dl for Gal. The detection limit was 0.14 mg/dl for Phe and 0.9 mg/dl for Gal. Reproducibility was assessed with filter paper blood specimens containing Gal and Phe at low, middle and high levels. Intraassay coefficients of variation were 10%, 7.5%, 6.22%, and 8.5%, 7%, 5%, respectively, whereas interassay coefficients of variation were 9.54%, 6%, 7% and 6%, 4.6%, 5.6%, respectively. In 1,000 samples from newborns, four samples of Phe and two samples of Gal showed a concentration below the threshold set for each assay. This method provides a rapid means to survey for a low incidence disease (i.e., galactosaemia: incidence, 1/30,000), in existing phenylketonuria analysis programs, where an incidence of 1/10,000), easily justifies the cost of mass screening.
推荐针对代谢紊乱开展新生儿筛查项目，尤其是苯丙酮尿症和先天性甲状腺功能减退症。本研究旨在调整、开发和评估一种用于测定滤纸血样中总半乳糖（Gal）和苯丙氨酸（Phe）的SUMA方法。用含血的单个5毫米圆盘，经甲醇 - 丙酮进行脱蛋白处理，并用蒸馏水洗脱。将10微升提取物转移至超微量酶联免疫吸附测定板的一个孔中，并加入反应溶液以测定苯丙氨酸水平。剩余提取物用于半乳糖测定。该方法在苯丙氨酸浓度范围为0 - 50mg/dl和半乳糖浓度范围为0 - 60mg/dl时显示出良好的线性。苯丙氨酸的检测限为0.14mg/dl，半乳糖的检测限为0.9mg/dl。使用含低、中、高水平半乳糖和苯丙氨酸的滤纸血样评估重现性。批内变异系数分别为10%、7.5%、6.22%和8.5%、7%、5%，而批间变异系数分别为9.54%、6%、7%和6%、4.6%、5.6%。在1000份新生儿样本中，有4份苯丙氨酸样本和2份半乳糖样本的浓度低于各检测设定的阈值。该方法为在现有的苯丙酮尿症分析项目中筛查低发病率疾病（即半乳糖血症：发病率为1/30,000，而苯丙酮尿症发病率为1/10,000）提供了一种快速手段，很容易证明大规模筛查的成本是合理的。
