To analyze differences of serum proteins measurements by different methods in different systems and investigate whether the assigned serum valued by ERM-DA470k/ IFCC can replace ERM-DA470k/IFCC in clinical measurements to promote the harmonization of serum proteins measurements.

Serum specimen was collected from 100 medical examination persons in Zhongshan Hospital (Jun 2012; age:27-73; 47 male and 53 female).Serum IgA,IgG,IgM,C3c,C4,TRF and PA of health persons,ERM-DA470k/IFCC and the assigned valued by ERM-DA470k/IFCC were measured by Hitachi 7600 (Roche and DiaSys reagents),Siemens BNⅡ (Siemens reagent) and Beckman IMMAGE (Beckman reagent),respectively.ERM-DA470k/IFCC was used as a calibrator to value the mixed serum.Serum proteins results obtained from the same methods were compared by T test and Wilcoxon test,and analysis of variance and Firendman test were used to compare results from different methods.The correlation of two groups was analyzed by linear regression.

The differences of serum proteins results measured by two immunonephelometries,two immunoturbidimetries and all assays were statistically significant (P<0.05),respectively.The serum proteins results measured by two immunoturbidimetries showed good correlation (R² were all above 0.97 except for C3c).In contrast,the serum proteins results measured by two immunonephelometries show poor correlation (R² were all ranged from 0.90 to 0.94) except for IgM (above 0.96).The serum Ig A,IgG and Ig M results measured by different methods show good correlation (R² were all above 0.95) Based on certified values of ERM-DA470k/IFCC,serum protein results measured by different methods could be harmonized,and got similar results from the assigned serum (P>0.05).

There is significant difference of serum proteins results detected by different methods.The ERM-DA470k/IFCC and certified serum can make serum protein results obtained from different methods harmonized.(Chin J Lab Med,2013,36:839-844)

Blood proteins; Reference standards; Reproducibility of results