Moore G I, Hochberg C J
South Med J. 1977 Sep;70(9):1093-5. doi: 10.1097/00007611-197709000-00025.
Several methods have been developed for analyzing amniotic fluid to aid in the management of rhesus isoimmunization. Because all methods attempt to predict the severity of fetal hemolysis based on the original findings of Bevis and on the amount of unconjugated bilirubin in amniotic fluid as measured by its optical density at 450 millimicron, they share two possible sources of error: calculation of exact gestational age and accurately reading bloody or contaminated amniotic fluid. The Ovenstone Factor measures the derivative of the bilirubin curve against wavelength and thereby avoids some of the contaminating pigments at 450 millimicron. This paper compares the predictive accuracy of two methods, Liley versus Ovenstone Factor, in 78 samples of fluid from 46 patients. Predictions were correct in 80% of infants using Ovenstone Factor and 67% using the Liley curve, and incorrect in only 7% and 13%, respectively. The Ovenstone Factor, with its simplicity and high predictive accuracy, is an excellent additional tool in the management of Rh-sensitized pregnancies.
已经开发出几种分析羊水的方法，以辅助管理恒河猴血型不合免疫。由于所有方法都试图根据贝维斯的原始发现以及通过羊水在450毫微米处的光密度测量的未结合胆红素量来预测胎儿溶血的严重程度，它们都有两个可能的误差来源：准确计算胎龄和准确读取血性或受污染的羊水。奥文斯通因子测量胆红素曲线相对于波长的导数，从而避免了450毫微米处的一些污染色素。本文比较了两种方法，即利利法与奥文斯通因子法，对46例患者的78份羊水样本的预测准确性。使用奥文斯通因子法，80%的婴儿预测正确，使用利利曲线法为67%，分别只有7%和13%的预测错误。奥文斯通因子法操作简单且预测准确性高，是管理Rh致敏妊娠的优秀辅助工具。
