Cotton D B, Spillman T, Bretaudiere J P
Clin Chim Acta. 1984 Mar 13;137(3):299-304. doi: 10.1016/0009-8981(84)90118-9.
Amniotic phospholipid detection methods such as cupric acetate measure unsaturated lecithin whereas others such as phosphomolybdate detect both unsaturated and saturated lecithin. Because of the extreme unsaturation in serum and red blood cell lecithin, we compared lecithin (L) and sphingomyelin (S) content of maternal blood as well as the effect of blood contamination on amniotic fluid L/S ratios. L/S ratios were obtained by thin-layer chromatography utilizing both cupric acetate and phosphomolybdate for phospholipid detection. The L/S value (mean +/- SD) of maternal serum obtained by cupric acetate was 1.90 +/- 0.19 and that for phosphomolybdate 1.78 +/- 0.17. The results of increasing serum concentrations in amniotic fluid prior to analysis suggest that as little as 0.5% contamination alter results and by 2% contamination values approach the L/S ratio of actual serum whether the amniotic fluid was initially mature or immature by either method. The serum L/S ratio by cupric acetate equaled its maturity threshold of 2.0 while the serum L/S ratio by phosphomolybdate was below its threshold of 3.0. Whereas both methods would have falsely immature values in the presence of blood only phosphomolybdate would assure against false maturity.
羊膜磷脂检测方法，如醋酸铜法可测量不饱和卵磷脂，而其他方法，如磷钼酸盐法可检测不饱和及饱和卵磷脂。由于血清和红细胞卵磷脂的极度不饱和性，我们比较了母血中卵磷脂（L）和鞘磷脂（S）的含量以及血液污染对羊水L/S比值的影响。L/S比值通过薄层色谱法获得，同时使用醋酸铜和磷钼酸盐检测磷脂。用醋酸铜测得的母血L/S值（均值±标准差）为1.90±0.19，用磷钼酸盐测得的值为1.78±0.17。分析前在羊水中增加血清浓度的结果表明，低至0.5%的污染就会改变结果，而2%的污染时，无论羊水最初用哪种方法检测是成熟还是未成熟，其值都接近实际血清的L/S比值。用醋酸铜测得的血清L/S比值等于其成熟阈值2.0，而用磷钼酸盐测得的血清L/S比值低于其阈值3.0。虽然两种方法在有血液存在时都会得出假未成熟值，但只有磷钼酸盐法能确保不会出现假成熟。
