The CLIA TEa for AST is 20%. The standard deviation of the assay as determined last month's data (30 Level 1 controls with a mean of 20 IU/L) was 2.0 IU/L. Determine whether the new method be acceptable at a concentration of 20 IU/L. This data came from a study serum versus plasma for normal subjects; thus, the limited range of concentration. Also, what problem is evident from the scatterplot?

This is a linear regression analysis from the study comparing heparin to serum (the reference) for aspartate aminotransferase to see if they are equivalent (attached). The CLIA TEa for AST is 20%. The standard deviation of the assay is 2.0 IU/L. Determine whether the new method is acceptable at a concentration of 20 IU/L. Discuss two limitations of this study evident from the scatterplot.

AST y = 17.92 + 0.50x 35 30 HEPARIN IU/L 25 20 15 20 25 30 35 40 SERUM IU/L