Evaluation of performance of NM-BAPTA method in detecting serum calcium

Objective To evaluate the performance of the reagent kit for detecting serum calcium by NM-BAPTA method. Method According to Clinical and Laboratory Standards Institute (CLSI) evaluation protocols——EP15-A2, EP9-A2, EP6-A, and C28-A2, the precision, accuracy, linearity, and reference interval of NM-BAPTA method in detecting serum calcium by Hitachi 7180 biochemistry analyzer were validated. Results The repeatability and within-laboratory precision standard deviation (SD) of both high and low levels of serum calcium quality control were 0.03 mmol/L, 0.02 mmol/L, and 0.08 mmol/L, 0.06 mmol/L, respectively. During the accuracy test, the relative bias was less than 12.5%, r2=0.954 8, which accorded with reference system. The results showed that the linearity slop was 0.971 and r2=0.999. It had a good linearity from 1.00 to 4.70 mmol/L. The biotic reference intervals 100% matched with the current biotic reference intervals. Conclusion The NM-BAPTA method in detecting serum calcium by Hitachi 7180 biochemistry analyzer shows a good performance and can be widely used in clinical laboratory. Key words: Total calcium; NM-BAPTA method; Hitachi 7180 biochemistry analyzer; Performance evaluation