核酸检测室内质控评价和关键控制点分析

Application of control chart in the internal quality control of NAT

目的探讨核酸扩增检测(nucleic acid amplification test,NAT)的室内质控评价方法及关键控制点。方法对NAT阳性标本病毒载量的自然对数(lnc)与Ct值进行相关性分析,利用"即刻法转L-J质控图法"对Ct值进行质控。将低浓度质控品按4℃保存时间不同分为7组,进行核酸检测,分析4℃保存时间对Ct值的影响。结果NAT阳性标本的Ct值与lnc的相关系数r=-0.901(P<0.01)。质控品在4℃保存72 h后与0 h组比较,差异有统计学意义。结论应用质控图法进行NAT室内质控是可行的,4℃长时间保存对质控品的Ct值影响较大。

Objective To discuss the evaluation methods of internal quality control and critical control points in nucleic acid amplification test （NAT）. Methods The correlation between NAT positive samples of viral load natural logarithm （lnc） and the Ct value were analyzed. An approach of ＂instant method to L-J control chart＂ was employed to control the quality of Ct value. The low concentration of control materials were stored at 4℃ for different amount of time and divided into seven groups to perform NAT test. The impact of time on the Ct values was analyzed. Results The correlation coefficient （r） between Ct value and lnc of NAT positive samples was equal to - 0. 901 （ P 〈 0. 01 ）. Comparing the materials stored at 4℃ for 72 h and 0 h in control, the difference was statistically significant. Conclusion It is feasible that the ＂control chart method＂ was used in NAT internal quality control. The Ct value of control material exhibited significant change with the in- crease of storage time at 4℃.