Improve the consistency of C-reactive protein test results using trueness control material / 中华检验医学杂志

ABSTRACT

Objective To explore the CRP harmonization by calibration using commutable trueness verification materials. Methods High and low level of CRP concentrations trueness verification materials(H and L) were prepared by Beijing center for clinical laboratories. Thesetrueness verification materials were diluted to 5 calibration points(5L, 4L+1H, 3L+2H, 1L+4H, 5H) by weighing method, respectively. These 5 points were used to calibrate four different brands of CRP detection system (Diasys, Leadman, Siemens and Roche) instead of the original procedure. Sera from 21 patients and the international standard ERM DA-474/IFCC were used to compare harmonization and trueness after calibration. Each sample above was measured twice. Results After calibration, the median of CV was reduced from 19.33％ to 2.92％ among 21 patient samples, less than the optimal CV based on biological variability (CV=10.6％). Compared with Desai, the slopes were closer to 1 from 0.90-1.09 to 0.93-0.96 after calibration. Meanwhile, if ERM-DA474/IFCC was used as the trueness verification materials, the absolute bias wasreduced from 3.08-11.07 mg/L to 0.52-2.97 mg/L which was close to theuncertainty of itself (2.5 mg/L). Conclusions Afterthe calibration which contained five linear concentration points of CRP trueness verification materials by weighing method, both harmonization and trueness of CRP were improved.