Analyte comparisons between 2 clinical chemistry analyzers

Abstract

The purpose of this study was to assess agreement between a wet reagent and a dry reagent analyzer. Thirteen analytes (albumin, globulin, alkaline phosphatase, alanine aminotransferase, amylase, urea nitrogen, calcium, cholesterol, creatinine, glucose, potassium, total bilirubin, and total protein) for both canine and feline serum were evaluated. Concordance correlations, linear regression, and plots of difference against mean were used to analyze the data. Concordance correlations were excellent for 8 of 13 analytes (r > or = 0.90); the correlations for albumin, potassium, and calcium were clinically unreliable. The linear regression analysis revealed that several analytes had slopes significantly different from unity, which was likely related to methodological differences. Compared to the wet reagent analyzer, the dry reagent analyzer showed excellent agreement for alkaline phosphatase, alanine aminotransferase, amylase (feline), urea nitrogen, cholesterol, creatinine, glucose, total bilirubin (canine), and total protein. However, it showed only slight to substantial agreement for amylase (canine), calcium, albumin, potassium, and total bilirubin (feline).