Evaluation of analytical performance of two iPTH immunoassay methods in hemodialysis patients

INTRODUCTION: Renal excretion of parathormone (PTH) C-terminal fragments can cause an accumulation of the C-terminal form in the blood in chronic kidney disease patients. Thus, the measurement of the active form of PTH has become important. This study was designed to compare the Architect iPTH test measured using the Architect i2000SR System (Abbott Laboratories, Lake Bluff, IL, USA) and the Beckman iPTH test measured using the Beckman Coulter Dxi 800 (Beckman Coulter, Brea, CA, USA), which are 2 immunoassay systems commonly used in routine laboratory analyses, and to evaluate the analytical performance in hemodialysis patients.
METHODS: The immunoassays were assessed for accuracy, precision, limit of blank (LoB), limit of detection (LoD), and limit of quantification (LoQ).
RESULTS: A total of 86 samples were run on both systems and the correlation between the methods was evaluated. The i2000SR and Dxi 800 assays demonstrated good performance in terms of precision, accuracy, LoB, LoD, and LoQ. Intraclass correlation coefficient analysis revealed a difference of 0.912 (0.489-0.968) with a y=2.58+1.53x equation.
DISCUSSION AND CONCLUSION: It was confirmed that these analyzers widely used for iPTH measurement operate at an acceptable level of analytical performance. It was observed that the measurements obtained from both analyzers were consistent, but the Abbott Architect i2000SR provided higher results than the Beckman Coulter Dxi800. For consistency, is suggested that patient follow-up should be performed using the same kits, the same analysis system, and in the same laboratory.