Moir M, Holbrook R H
Department of Gynecology and Obstetrics, Stanford University School of Medicine, California.
Obstet Gynecol. 1993 May;81(5 ( Pt 1)):793-6.
In funipuncture, fetal blood is collected by passing a needle transabdominally into an umbilical vessel under ultrasound guidance. The objective of this study was to develop an accurate, inexpensive test that immediately indicates the source of the blood during the umbilical sampling procedure, ie, before the needle is withdrawn. To distinguish fetal from adult blood, we used a modified version of the Apt test, which is based on the different alkaline denaturation properties of adult hemoglobin and fetal hemoglobin. We collected 18 blood samples from adult volunteers and 22 umbilical cord samples from deliveries occurring between 25-42 weeks' gestation. The samples were tested for character and time of color change upon addition of increasing concentrations of NaOH. We found 0.2N NaOH to be the ideal concentration to add to hemolyzed blood samples for a reliable determination of blood origin. All of the hemolysates tested in blinded trials using 0.2N NaOH were correctly identified as fetal or adult. The increase in adult hemoglobin due to the increase in gestational age alters the rate of color change, but the difference was not clinically important because it did not alter the efficacy of the alkaline denaturation test.
在脐静脉穿刺术中，在超声引导下经腹将针插入脐血管来采集胎儿血液。本研究的目的是开发一种准确、廉价的检测方法，能在脐血采样过程中，即在拔出针头之前，立即指示出血液来源。为了区分胎儿血和成人血，我们使用了改良版的阿普特试验，该试验基于成人血红蛋白和胎儿血红蛋白不同的碱性变性特性。我们从成年志愿者身上采集了18份血样，并从妊娠25至42周分娩的产妇身上采集了22份脐带血样。对样本添加不同浓度氢氧化钠后颜色变化的特征和时间进行了检测。我们发现0.2N氢氧化钠是添加到溶血血液样本中用于可靠确定血液来源的理想浓度。在使用0.2N氢氧化钠的盲法试验中检测的所有溶血产物都被正确鉴定为胎儿血或成人血。由于胎龄增加导致成人血红蛋白增加，这改变了颜色变化的速率，但这种差异在临床上并不重要，因为它没有改变碱性变性试验的效果。
