Laboratory Medicine ›› 2021, Vol. 36 ›› Issue (3): 263-269.DOI: 10.3969/j.issn.1673-8640.2021.03.007

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Isotope dilution mass spectrometry applied in measurement uncertainty of serum creatinine concentration

ZHANG Weiwei, JING Rongrong, JI Huoyan, WANG Jianxin, WANG Feng, WANG Huimin()   

  1. Department of Clinical Laboratory,Affiliated Hospital of Nantong University,Nantong 226001,Jiangsu,China
  • Received:2020-12-01 Online:2021-03-30 Published:2021-03-30
  • Contact: WANG Huimin

Abstract:

Objective To investigate the evaluation method for measurement uncertainties of serum creatinine concentration by isotope dilution mass spectrometry(ID-MS). Methods We established a reference measurement procedure for the serum creatinine concentration by ID-MS. The uncertainty was evaluated according to the strict Guide to the Expression of Measurement Uncertainty(GUM) method. The strict GUM method meant that each uncertain component was analyzed and quantified in detail according to the measurement model. The calculation was based on the principle that relative values should be used in multiplication and division,and absolute values should be used in addition and subtraction. Meanwhile,traditional evaluation method and the Monte Carlo method(MCM) were used to evaluate the uncertainties of serum creatinine concentration. Results The measured specific serum creatinine concentration was 347.4 μmol/L. The combined standard uncertainty was 0.89% according to ID-MS measurement model and strict GUM principle. The uncertainty evaluated by the traditional method was 0.93%,which was 4.8% higher than that evaluated by the GUM method. The combined standard uncertainty was 0.64% by MCM,which was 27.9% lower than that evaluated by the strict GUM method. The 95% confidence interval of the measurement result by MCM was 343.1-351.8 μmol/L. Conclusions The result of uncertainty evaluated by the traditional method is higher than that of the strict GUM method,while the result of the MCM is lower than that of the strict GUM method. It is suggested that each uncertainty component should be strictly quantified and combined according to the GUM method. If possible,the MCM could be used to evaluate the uncertainty.

Key words: Isotope dilution mass spectrometry, Serum creatinine concentration, Measurement uncertainty, Monte Carlo method

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