BACKGROUND: IDS-iSYS intact parathyroid hormone (iPTH) assay was evaluated. Two automated second generation assays for measuring iPTH were also compared to each other. The compared assays detected PTH fragments 1-84 and 5-84. METHODS: The iPTH was analyzed from controls (n = 88) and samples of patients with chronic kidney disease (CKD) (n = 100) on the IDS-iSYS (iSYS) and Siemens ADVIA Centaur (Centaur) immunoanalyzers. RESULTS: In controls, the iSYS method mean value (95% CI ranges) was 37.1 pg/mL (34.3 to 39.9) and the Centaur was 39.3 pg/mL (36.3 to 42.3). The regression coefficient (r) between the iSYS and the Centaur was 0.850 in controls. Correspondingly, in CKD patients the iSYS method mean value (95% CI ranges) was 183.3 pg/mL (154.3 to 212.4) and the Centaur was 199.7 pg/mL (170.4 to 229.0). In CKD patients the regression coefficient (r) between the iSYS and the Centaur was 0.964. With Passing-Bablok analysis, the automated iPTH methods gave clinically similar results in controls and in CKD patients. However, in the difference blots, the iSYS gave lower concentrations when the mean concentration increased. CONCLUSIONS: The IDS-iSYS iPTH assay is precise. The iSYS concentrations of iPTH were clinically similar with those determined by Centaur.
BACKGROUND:IDS-iSYS intact parathyroid hormone (iPTH) assay was evaluated. Two automated second generation assays for measuring iPTH were also compared to each other. The compared assays detected PTH fragments 1-84 and 5-84. METHODS: The iPTH was analyzed from controls (n = 88) and samples of patients with chronic kidney disease (CKD) (n = 100) on the IDS-iSYS (iSYS) and Siemens ADVIA Centaur (Centaur) immunoanalyzers. RESULTS: In controls, the iSYS method mean value (95% CI ranges) was 37.1 pg/mL (34.3 to 39.9) and the Centaur was 39.3 pg/mL (36.3 to 42.3). The regression coefficient (r) between the iSYS and the Centaur was 0.850 in controls. Correspondingly, in CKDpatients the iSYS method mean value (95% CI ranges) was 183.3 pg/mL (154.3 to 212.4) and the Centaur was 199.7 pg/mL (170.4 to 229.0). In CKDpatients the regression coefficient (r) between the iSYS and the Centaur was 0.964. With Passing-Bablok analysis, the automated iPTH methods gave clinically similar results in controls and in CKDpatients. However, in the difference blots, the iSYS gave lower concentrations when the mean concentration increased. CONCLUSIONS: The IDS-iSYS iPTH assay is precise. The iSYS concentrations of iPTH were clinically similar with those determined by Centaur.