Abstract:

Objective To analyze the external quality assessment（EQA） results for 25-hydroxyvitamin D[25（OH）D] in Shanghai from 2015 to 2019,and to provide experimental data for the improvement of 25（OH）D testing. Methods Ten rounds of EQA results for 25（OH）D in Shanghai Center for Clinical Laboratory（SCCL） from 2015 to 2019 were collected. The means（x）, standard deviation（s） and coefficient of variation（CV） were calculated after eliminating outliers. Results The number of laboratories participating in EQA increased from 41 in 2015 to 83 in 2019. The percent of pass of the 10 EQA in the 5 years were 65.85%,74.70%,82.00%,83.67%,90.91%,87.50%,86.67%,91.89%,92.68% and 92.77%,respectively. The main detection methods were electrochemical luminescence and chemiluminescence,and enzyme-linked immunosorbent assay and liquid chromatography tandem-mass spectrometry were used in a few laboratories. A total of 50 batches were tested in 5 years,among which 33 batches showed a CV less than 20%,6 batches were between 20% and 30%,and the rest were more than 30%. Conclusion There is a large variation of 25（OH）D testing results among different laboratories in Shanghai. It is needed to strengthen the laboratory quality management,to impel the standardization of 25（OH）D testing and to promote the mutual recognition of laboratory test results.

Key words: External quality assessment, 25-hydroxyvitamin D, Quality control