SAT-387 Testing for Parathyroid Hormone: Performances of a Novel Fully Chemiluminescent Automated Assay

Background: Parathyroid hormone (PTH) is one of the key regulators of the bone and mineral metabolism. Testing for PTH is essential for the management of hyper- or hypo calcemia. Measurement of PTH is also an important tool for the monitoring of patient with chronic kidney diseases. Our study objective was to determine the performances of a novel fully automated chemiluminescent assay for testing of intact PTH. Methods: We evaluated the Maglumi® (Snibe) PTH assay a fully automated two-sites immunoluminometric method based on a solid-phase, paramagnetic microbeads, coated with a monoclonal antibody targeting PTH epitopes. Assay imprecision was assessed with two levels of control materials. Reference values were determined with samples of 24 healthy volunteers. Method comparison was performed with an electrochemiluminescent immunoassay (ECLIA) (Roche diagnostics) with 24 patients’ samples. Results: The between-run coefficients of variation of the Maglumi® PTH assay were 5.1 and 3.7 % for concentrations of 33 and 992 pg/mL, respectively. The median PTH levels were 121 pg/mL (range: 18 - 369) with the Maglumi assay and 117 pg/mL with the ECLIA method (range: 10 - 482). The upper limit of the reference interval in the healthy volunteers was 63 pg/mL. The correlation between the both methods was good (r=0.87, p<0,001). Passing-Bablok regression analysis showed a slope of 0.96 (95% confidence interval (CI): 0.83 to 1.35) and an intercept of -2.14 (95% CI: -20.49 to -10.47). Bland-Altman plot evidenced a bias between the methods with a mean bias of 4.6 pg/mL. Conclusions: Our preliminary data showed excellent concordance and analytical performances for the PTH fully automated immunoassay associated to perspectives of automation and reduction of turn-around time of analysis.