The performance evaluation of four Lp-PLA2 activity assays / 中华检验医学杂志

ABSTRACT

Objective To evaluate the analytical performance of four lipoprotein associated phospholipase A2(Lp-PLA2)activity reagents on Beckman AU5800 automatic biochemical analyzer. Methods The remaining serum samples of 214 patients and 140 apparently healthy individuals were collected from March to July 2017 in Peking Union Medical College Hospital.These samples were used for method comparison and reference interval evaluation.According to the guidelines of EP15-A,EP6-A,EP-17 and EP7-P from Clinical and Laboratory Standards Institute(CLSI)standards,the precision, linearity, sensitivity and common interferences(e.g free bilirubin, conjunct bilirubin, hemoglobin and chyle)were assessed.According to EP9-A2,method comparisons of differents regents(Evermed,DiaSys,Hengxiao and Zhongyuan were labeled as A,B,C and D,respectively)were conducted and the differences were estimated at medical decision levels(328U/L,391U/L and 485U/L).Results The precision of four reagents were acceptable.The repeatability(CV%)of A to D were 0.5%-1.7%, 0.7%-3.0%, 0.9%-2.0% and 0.5%-3.3%,respectively.The reproducibility(CV%)were 0.7%-2.9%, 1.4%-3.2%, 1.3%-1.9%and 0.8%-4.1%,respectively.Both of those achievedlaboratory defined quality objective(<5%).The linearity of A to D were 44 -1 992 U/L,39 -1 798 U/L,13 -540 U/L and 75-1 717U/L,respectively.The regression coefficient R2 was between 0.997 and 1.000, and the correlation coefficient(r)was between 0.998 and 1.000.The interference of chyle were acceptable among these four reagents andmet the manufacturer′s requirementsor clinical needs.In a low level of Lp-PLA2,bilirubin had an obvious interferenceonreagent C;B and C were negatively affected when the hemoglobin was 4.5 g/L; and D was positively affected when the hemoglobin was 2.45 g/L.The regression coefficients R2 of A,C,D compared with B were between 0.978 and 0.995,and the correlation coefficients(r)were between 0.989 and 0.998. The expected differences at medical decision levels ranged from -240 U/L to 113 U/L.For A to D,the Lp-PLA2 activity results of 131(93.6%), 140(100%), 82(58.6%), and 128(91.4%)cases were analysed within the manufacturer′s claimed reference intervals.Conclusion The precision and linearity of the four Lp-PLA2 activity detection reagents used in automatic biochemical analyzer are good, but the anti-interference ability needs to be improved.