Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Oct 1;32(3):030402.
doi: 10.11613/BM.2022.030402. Epub 2022 Oct 1.

Bias, the unfinished symphony

Abdurrahman Coşkun  1   2
Affiliations

Bias, the unfinished symphony

Abdurrahman Coşkun. Biochem Med (Zagreb). .

Abstract

In laboratory medicine, mathematical equations are frequently used to calculate various parameters including bias, imprecision, measurement uncertainty, sigma metric (SM), creatinine clearance, LDL-cholesterol concentration, etc. Mathematical equations have strict limitations and cannot be used in all situations and are not open to manipulations. Recently, a paper "Bias estimation for Sigma metric calculation: Arithmetic mean versus quadratic mean" was published in Biochemia Medica. In the paper, the author criticized the approach of taking the arithmetic mean of the multiple biases to obtain a single bias and proposed a quadratic method to estimate the overall bias using external quality assurance services (EQAS) data for SM calculation. This approach does not fit the purpose and it should be noted that using the correct equation in calculations is as important as using the correct reagent in the measurement of the analytes, therefore before using an equation, its suitability should be checked and confirmed.

Keywords: bias; pooled variances; sigma metric.

PubMed Disclaimer

Conflict of interest statement

Potential conflict of interest None declared.

Figures

Figure 1
Figure 1
Bias is the mean of the replicate measurement results minus a reference quantity value. CI – confidence interval.
See this image and copyright information in PMC

Comment in

References

    1. Ercan Ş. Bias estimation for Sigma metric calculation: arithmetic mean versus quadratic mean. Biochem Med (Zagreb). 2022;32:030401. 10.11613/BM.2022.030401 - DOI - PMC - PubMed
    1. Keleş M. Evaluation of the clinical chemistry tests analytical performance with Sigma Metric by using different quality specifications - Comparison of analyser actual performance with manufacturer data. Biochem Med (Zagreb). 2022;32:010703. 10.11613/BM.2022.010703 - DOI - PMC - PubMed
    1. International vocabulary of metrology — Basic and general concepts and associated terms (VIM) 3rd ed. JCGM [Internet]. 2012. Available from: https://www.bipm.org/documents/20126/2071204/JCGM_200_2012.pdf/f0e1ad45-...
    1. Taylor BNKC. NIST Technical Note 1297. Guidelines for Evaluation and Expressing the Uncertainty of NIST Measurement Results. NIST; 1994.
    1. Coskun A, Serteser M, Ünsal I. The short story of the long-term Sigma metric: shift cannot be treated as a linear parameter. Clin Chem Lab Med. 2019;57:e211–3. 10.1515/cclm-2018-1139 - DOI - PubMed