Abstract:

Objective To discuss the influence of different-brand calibrators and matrix on the comparability of alkaline phosphatase（ALP） determination,and to provide a reference for further standardization of serum ALP determination and clinical result mutual accreditation. Methods ALP was calibrated on AU5800 analyzer and cobas c501 analyzer by 2 commonly used calibrators（AU calibration and C.f.a.s. calibration） and ALP national secondary reference material. Totally,25 fresh clinical samples and 5 concentration level samples of routine chemistry of Shanghai external quality assessment were determined for 2 times. Taking the test value after calibration of the reference material as the reference system,the bias and correlation between determination values after calibrating the matching calibration and reference material were calculated. Taking the determination value of the c501 as the reference system,the bias and correlation between determination values obtained by the 2 instruments after the same calibrator were calculated and calibrated. Results Taking the determination value after calibration of the reference material as the reference system,the absolute value of the bias of the 2 systems was <10%. The c501 had a negative bias,while the AU5800 had a positive bias. There was no statistical significance in the bias between the external quality assessment samples and the clinical samples. Taking c501 determination value as the reference system,after using reference material to calibrate clinical serum samples,the differences between the systems were reduced. After the calibration of the non-matching system,the differences between the systems were increased. The external quality assessment samples presented the opposite results from the serum samples. Conclusions The use of traceability and commutability reference materials is beneficial to the consistency and comparability of the determination results between different determination systems and laboratories. The use of non-matching system calibrators will increase the differences between systems and will not be interchangeable. In addition,the external quality assessment samples with matrix effect can not fully show the real determination results of each system.

Key words: Alkaline phosphatase, Calibrator, Comparability, Commutability