Abstract:

Objective To set the allowable total error（TEa），allowable imprecision [coefficient of variation（CV）] and allowable bias（Bias） for 22 endocrine analytes，and to recommend performance specifications for related items. Methods The data，including external quality assessment（EQA） data and internal quality control（IQC） data，of the National Center for Clinical Laboratories from 2020 to 2022 were collected. According to the performance specification setting mode newly determined at the Milan conference in Italy，the performance specification was derived based on biological variation（BV）and current technology level. For the analytes with BV data，the percentage difference of EQA data and the in-control CV of month IQC data were compared with the 3-level evaluation criteria derived based on BV，and the percentage difference passing rate and CV passing rate of all-batch quality control materials were calculated. When the passing rate reached 80%，the performance specifications of this level met the requirements of the recommended performance specifications of the analyte. For the analytes without BV data or the analytes whose performance specifications at 3-level evaluation criteria derived based on BV could not be used as recommended performance specifications，the recommended TEa and allowable CV may be derived based on the current technology level. Based on the current technology level，the recommended TEa and allowable CV were derived，and then the allowable Bias was derived. Results TEa/allowable CV recommended for 22 endocrine analytes were as follows：free triiodothyronine 18.9%/6.5%，triiodothyronine 17.4%/7.1%，free thyroxine 25.0%/6.2%，thyroxine 20.0%/7.0%，thyroid-stimulating hormone 24.6%/8.9%，cortisol 26.3%/8.2%，estradiol 26.0%/7.5%，follicle-stimulating hormone 21.2%/6.2%，luteinizing hormone 25.0%/6.8%，progesterone 26.2%/9.3%，prolactin 18.7%/7.4%，testosterone 16.5%/6.3%，C-peptide 20.8%/8.3%，folate 29.5%/8.9%，insulin 25.0%/6.4%，thyroglobulin 28.2%/8.0%，parathyroid hormone 30.0%/11.8%，aldosterone 21.4%/9.2%，dehydroepiandrosterone sulfate 25.0%/7.5%，vitamin B₁₂ 25.0%/7.5%，growth hormone 25.0%/7.0% and adrenocorticotropic hormone 27.4%/9.1%. Conclusions For 22 endocrine analytes，the TEa，allowable CV and allowable Bias that meet the current technology level of Chinese clinical laboratories are recommended.

Key words: Biological variation, Allowable total error, Allowable imprecision, Allowable bias, Endocrine, Performance specification