通过对中南地区１５７７例正常人的血清α_１－抗胰蛋白酶（α_１－ＡＴ）水平的测定，结果２０～４０岁组正常值为１３６．９ｍｇ％，４１～６０岁组正常值为１２９．３ｍｇ％，男女性别间的α_１－ＡＴ水平差异无显著意义。而两个年龄组间差异有显著意义。并对测定结果作了分型。 By measuring the level of serum α 1 -antitrypsin (α 1 -AT) in 1577 normal people in the central and southern regions, the normal value in the 20 to 40 year old group was 136.9 mg%, and the normal value in the 41 to 60 year old group was 129.3 mg%. There was no significant difference in the level of α_1-AT between men and women. The difference between the two age groups was significant. The test results were typed.