2017 ACVIM Forum Research Abstract Program

Intact PTH concentrations were measured using an immunoradiometric assay (IRMA) (Scantibodies) and a chemiluminescent assay (CLIA) (Immulite 2000) designed for human use, and a canine specific enzyme-linked immunosorbent assay (ELISA) (Immutopics). Samples, in duplicate, were assessed using each technique within 4 hours of each other. 45 and 48 samples, respectively, were available for comparison between IRMA and ELISA and IRMA and CLIA. Correlation between ELISA and IRMA was good (r = 0.90 (95% CI 0.83-0.95), P < 0.001). Bland-Altman difference plot revealed a bias with ELISA results greater than IRMA values by a mean AE sd of 80.74 AE 89.51% (95% CI -94.7-256.2)). Using CLIA, 39 (81.3%) samples had iPTH concentrations at or below the reported limit of detection of the assay (3.0 pg/mL). The remaining nine dogs had detectable but low concentrations ranging from 4.82-452.0 pg/mL. By comparison these values were higher by IRMA (range, 125.55 -867.73 pg/mL).