Analytical quality assessment and method comparison of immunoassaysfor the measurement of serum cobalamin and folate in dogs andcats

摘要

Serum cobalamin and folate are often measured in cats and dogs as part oflaboratory testing for intestinal disease, small intestinal dysbiosis, orexocrine pancreatic deficiency. We performed an analytical validation of humanimmunoassays for cobalamin and folate measurement (AIA-900 analyzer, TosohBioscience) and compared results with those obtained using chemiluminescenceassays (Immulite 2000 analyzer, Siemens Medical Solutions Diagnostics).Accuracy, precision, total observable error (TE %), and σ valueswere calculated for the immunoassays. Correlation and agreement were evaluatedwith Deming regression, Passing–Bablok regression, and Bland–Altman analysis.Cobalamin intra-assay and inter-assay CVs were 1.8–9.3% and 2.6–6.8%,respectively. Folate intra-assay and inter-assay CVs were 1.5–9.1% and 3.4–8.1%,respectively. TE (%) were ≤19 and ≤31 for cobalamin and folate,respectively. Sigma values were 3.60–11.50 for cobalamin and 2.90–7.50 forfolate. Regression analysis demonstrated very high or high correlations forcobalamin [ = 0.98 (dogs), 0.97 (cats)] and folate[ = 0.88 (dogs), 0.92 (cats)] but Bland–Altman analysisrevealed poor agreement for both. The immunoassays had good analyticalperformance for measuring cobalamin and folate in both species. Results obtainedby the 2 analyzers cannot be used interchangeably and should be interpretedusing instrument-specific reference intervals. Further studies are required toestablish immunoassay-specific reference intervals and to evaluate thediagnostic performance and clinical utility of the analyzer for theseanalytes.