Preliminary assigning values of reference materials for AST and α-Amy

Objective To assign the activity values of the reference materials for AST and α-Amy.Methods The activities of the two enzymes were determined using the method proposed by IFCC.The collaborative study involved 8 laboratories in Nanjing city Their instruments were checked and the actual K values were determined just before assay.Results Between-vial variability was less than 1.1%(CV). The between-lab variance was greater than either the within-day within-lab or the between-day between-lab variance.The assigned catalytic concentration for α-Amy and AST in the reconstituted lyophilized materials with a 0.95 confidence interval were 1048±42U/L and 182±5 U/L respectively .Similarly the materials of liquid form were 1198±43 U/L and 172±3 U/L.When the reconstituted and liquid materials of Amy were diluted with equal volume of water,the assigned values were 598±22 U/L and 537±20 U/L respectively.Conclusion The preliminary assigned values of reference materials for AST and α-Amy are valuable for both trial use and certification campaign.