乙型肝炎表面抗原定性测定室内质控物浓度的选择方法

目的 建立定性酶联免疫吸附法(ELISA)测定室内质量控制质控物浓度选择和Levey-Jennings质控图在不同批试剂间连续作图的方法。 方法 以乙型肝炎表面抗原(HBsAg)的ELISA测定为例,先按NCCLs EP5文件评价方法对系列质控血清(含量分别为0.2、0.5、1.0、2.0和5.0 ng/ml)的批内和批间测定精密度,并根据任一次测定值(S/CO)最好的线性相关确定回归直线方程(y=bx a),选择计算得到的S/CO值减去精密度测定中得到的3倍批间CV％与该S/CO值的乘积(意即3倍SD)仍大于1的质控物,作为室内质控使用。不同批试剂间质控图的连续,则在换用新批号试剂时,用新批号试剂测定上述系列质控血清,得到一新的直线方程(y2=b2x2 a2)。原批号试剂同样也可得一直线方程(y1=b1x1 a1)。根据两个直线方程即可得到y2/y1之间的换算因子,从而可以将新批号试剂对相同室内质控血清的测定值换算回去,在原质控图上继续作图。结果 所用的HBsAg ELISA测定方法测定含量分别为0.2、0.5、1.0、2.0和5.0ng/ml质控血清的批内变异分别为11.08％、9.49％、9.83％、9.18％和7.25％,批间变异分别为13.25％、14.03％、15.11％、13.29％和9.92％。任选一次测定的具有最好相关的回归直线方程y=3.509x 0.180,可选择的室内质控血清浓度可为0.5或1.0ng/ml。换用其它两批

Selecting methods of controls concentration for internal quality control and continuity of control chart between different reagent lots for HBsAg qualitative detection

Objective To establish a model for one choosing controls with a suitable concentration for internal quality control (IQC) with qualitative ELISA detection, and a consecutive plotting method on Levey-Jennings control chart when reagent kit lot is changed. Methods First, a series of control serum with 0.2, 0.5, 1.0, 2.0 and S.O ng/ml HBsAg respectively were assessed for within-run and between-run precision according to NCCLs EPS document. Then, a linear regression equation (y=bx a) with best correlation coefficient (r>0.99) was established based on S/CO values of the series of control serum. Finally, one could choose controls with S/CO value calculated from the equation (y = bx a) minus the product of the S/CO value multiplying three-fold between-run CV to be still more than 1.0 for IQC use. For consecutive plotting on Levey-Jennings control chart when ELISA kit lot was changed, the new lot kits were used to detect the same series of HBsAg control serum as above. Then, a new linear regression equation (y2= b2x2 a2) with best correlation coefficient was obtained. The old one (y1 =b1x1 a1) could be obtained based on the mean values from above precision assessment. The S/CO value of a control serum detected by new lot kit could be changed to that detected by old kit lot based on the factor of y2/y1. Therefore, the plotting on primary Levey-Jennings control chart could be continued. Results The within-run coefficient of variation CV of the ELISA method for control serum with 0.2, 0.5, 1.0, 2.0 and 5.0 ng/ml HBsAg were 11.08%, 9.49%, 9.83%, 9.18% and 7.25%, respectively, and between-run CV were 13.25%, 14.03%, 15.11%, 13.29% and 9.92%. The linear regression equation with best correlation coefficient from a test at random was y = 3.509x 0.180. The suitable concentration of control serum for IQC could be 0.5 ng/ml or 1.0 ng/ml. The linear regression equation from the old lot and other two new lots of the ELISA kits were y1 = 3.550x1 0.226, y2 = 3.238x2 0.388, and y3=3.428x3 0.148, respectively. Then, the transferring factors of 0.960 (y2/y1) and 0.908 (y3/y1) were obtained. Conclusion The results shows that the model established for IQC control serum concentration selecting and for consecutive plotting on control chart when the reagent lot is changed is effective and practical.