Evaluation of the analytical performances of six measurands for thyroid functions of Mindray CL-2000i system

Abstract

Background: Diagnosis and monitoring of thyroid diseases are based on laboratory testing of thyroid stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4). Other thyroid markers, such as thyroglobulin (Tg), antibody against Tg (TgAb) and thyroperoxidase (TPOAb), are also widely utilized by physicians. The present study aimed to evaluate the analytical performances of the Mindray CL-2000i compared to other immunoassay systems. Methods: Analytical precision of CL-2000i was evaluated by using both third-part and manufacturer’s internal quality controls (IQC). One hundred fifty specimens were used for comparing TSH, FT3, FT4, Tg, TgAb, TPOAb in Mindray CL-2000i, Roche Cobas e601, Beckman Coulter Access Immunoassay system and LIAISON Diasorin systems. Method limit of detection (LOD) and linearity, as well as matrix exchange effects, were also evaluated. Results: At the most clinically relevant levels, Mindray CL-2000i repeatability results obtained by IQC were 3.52%, 1.29%, 3.62%, 2.07%, 4.31% and 4.34% for TSH, FT3, FT4, Tg, TPOAb and TgAb, respectively. Method comparison showed a full comparability between the Mindray CL-2000i and the Roche Cobas e601 for TSH and FT3, while a slight to moderate bias was present for the other measurands. Matrix effect was negligible for TSH and linearity assays demonstrated a good linearity for TSH and Tg. LOD were 0.0005 mUI/L (CV% =9.46) and 0.0936 (CV% =10.76) for TSH and Tg, respectively. Conclusions: Considering the current state-of-the-art of thyroid testing, the present study results support the comparability of the Mindray CL-2000i automated system with respect to other immunoassay methods. Additional features of CL-2000i were the good assays linearity and the very low LOD.