Evaluation of serum adenosine deaminase assays of different manufacturers and harmonization of test results

Objective To Evaluate the performance of serum adenosine deaminase assays of different manufacturers and explore the approach for harmonization of test results. Methods It was evaluated the indice including the limit of blank,precision,linearity range and reference interval of 10 test systems.It was as the reference system by Mindray test system to evaluate the comparability and the difference of ADA results among 10 different systems.The evaluation was performed before and after calibration by a selected fresh serum assigned by the reference system.A commercial calibrator of the minimum matrix effect was selected from 8 different calibrators as the long-term calibrator to harmonize the ADA results of 10 systems. Results The results of LoB were 0.1-6.3 U/L,respectively.The within-run CVs and total CVs of 10 systems were all less than 5% and actual linearity ranges were conformed to claims of manufacturers.After calibration with fresh serum calibrator,the averaged difference of 10 test systems was reduced from 14% to 3.0%,and the average difference was 1.8% after calibration with long-term calibrator.The common reference interval of all test systems was 5-24 U/L identically. Conclusions The comparability of ADA measurements can be improved by using a common human serum calibrator and the commutable commercial calibrator.And it is necessary and feasible to develop the standardzation of ADA. （Chin J Lab Med，2014,37：439-443） Key words: Adenosine deaminase; Reproducibility of results; Reference values