明确直接测定羊水中由神经组织特异分泌的AchE 活力诊断NTD_s,比间接了解从血液通过开放性病变进入羊水的AFP 更为特异与精确。与定量法相比,定性法分析羊水AchE 可更有效地克服AFP 的二个主要缺点:血污染及孕龄诊断困难者的误诊率增高。正常羊水(包括血污染)的AchE 可减少AFP 假阳性率88.7%(134/151)～94%(117/125)。NTD_S 的AchE 假阴性率1.0%(3/314)低于AFP4.1%(13/314)。显然,AchE 可作为羊水AFP 的辅助测定。最后推荐自16孕周起筛选NTD_s 的具体计划,以提高有效筛选率。 It is more specific and precise to directly determine the activity of AchE secreted by neural tissue in amniotic fluid to diagnose NTD_s, which is more specific and accurate than to indirectly understand the AFP that enters the amniotic fluid from the blood through open lesions. Compared with the quantitative method, qualitative analysis of amniotic fluid AchE can be more effectively overcome the two main drawbacks of AFP: blood contamination and gestational age diagnosed patients with increased misdiagnosis. AchE in normal amniotic fluid (including blood contamination) reduced the false-positive rate of AFP by 88.7% (134/151) to 94% (117/125). The AchE false negative rate of NTD_S was 1.0% (3/314) less than AFP4.1% (13/314). Obviously, AchE can be used as adjunctive determination of amniotic fluid AFP. Finally, we plan to screen specific programs of NTD_s from the 16th week of pregnancy to improve the effective screening rate.