结膜印迹细胞法检查维生素A缺乏能力的确证研究

Study on the method of conjunctival impression cytology to detect vitamin A deficiency

１９９５年８月至１９９６年１月，作者先后三次（基线时、补充后三个月及补充后五个月）用结膜印迹细胞法（ＣＩＣ）及血清学方法调查了河北省易县山区两所中学２８３名学生的维生素Ａ营养状况及补充后的变化情况，以验证ＣＩＣ用于现场检查维生素Ａ缺乏的能力。结果显示：ＣＩＣ的灵敏度、特异度和阳性预测值分别为：５１．４％、７２．２％及２３．５％。因此，它不宜用于检查个体维生素Ａ缺乏。但是，当用它来评价群体维生素Ａ的营养状况时，发现它能够将维生素Ａ营养状况良好的群体和维生素Ａ缺乏的群体区分开，而且，它的这一能力相对稳定。补充２０×１０４ＩＵ的维生素Ａ后，补充组的ＣＩＣ异常率在第二次调查时显著降低且低于对照组（Ｐ＜０．０１）。然而，此时补充组仍有１７．４％的受试者ＣＩＣ异常，第三次调查时仍维持于这一水平。试验结果提示结膜炎可能是影响ＣＩＣ结果的混杂因素。但是，没有发现砂眼和ＣＩＣ结果间存在相关关系。结膜印迹细胞转移法（ＩＣＴ）和ＣＩＣ结果的一致率高达９４．４％。单眼的ＣＩＣ异常率显著高于双眼的结果。但是，单眼的ＣＩＣ结果也能将相对剂量反应（ＲＤＲ）异常率相差较大的群体分开。

From August 1995 to January 1996, 283 middle school students were irivestigated for three times(baseline, three months and five months after supplementation )in a mountainous areas in Yi county, Hebei province to validate conjunctival imbression cytology(CIC) as an objective and field applicable method to detect vitamin A deficiency with the relative dose response(RDR)test as the' golden standard'. Results showed that CIC presented a sensitivity of 51.4%, a specificity of 72.2%and a positive predicition value of 23.5%. It can discriminate population who has high RDR abnormality from those who had a lower one with statistical significance, which was stable in populations of the same vitamin A status. After supplimentated with 200000 IU vitamin A,the abnormal CIC rate in supplementation group decreased significantly in the second survey, and it was also significantly lower than that of the control group (P<0. 01). But there was still a 17.4%abnormality in the supplementation group and remained in the last survey. Conjunctivitis was likely to be a confounding factor when using CIC in the survey, but no relationship was found between the active trachoma and abnormal CIC. The results of in1pression cytology with transfer (ICT)showed a high conformity rate, 94.4%with CIC. The abnormality of CIC on single eye, no matter right or left, was significantly higher than that on two eyes . However, single eye results could also distinguish population with high RDR abnormality from that with normal RDR.