Repeatability imprecision from analysis of duplicates of patient samples and control materials
| Autor: | Elvar Theodorsson, Anders Kallner |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Automation
Laboratory Observer Variation Quality Control Analysis of Variance Reproducibility Clinical Laboratory Medicine Clinical Biochemistry Uncertainty Reproducibility of Results Dahlberg formula analysis of variance components repeatability reproducibility total variance bias 030206 dentistry General Medicine Repeatability 03 medical and health sciences Klinisk laboratoriemedicin 0302 clinical medicine Bias Reference Values Case-Control Studies Chemistry Clinical Humans Control material 030212 general & internal medicine Biomedical engineering Mathematics |
| Popis: | Measurement imprecision is usually calculated from measurement results of the same stabilized control material(s) obtained over time, and is therefore, principally, only valid at the concentration(s) of the selected control material(s). The resulting uncertainty has been obtained under reproducibility conditions and corresponds to the conventional analytical goals. Furthermore, the commutability of the control materials used determines whether the imprecision calculated from the control materials reflects the imprecision of measuring patient samples. Imprecision estimated by measurements of patient samples uses fully commutable samples, freely available in the laboratories. It is commonly performed by calculating the results of routine patient samples measured twice each. Since the duplicates are usually analysed throughout the entire concentration interval of the patient samples processed in the laboratory, the result will be a weighted average of the repeatability imprecision measured in the chosen measurement intervals or throughout the entire interval of concentrations encountered in patient care. In contrast, the uncertainty derived from many measurements of control materials over periods of weeks is usually made under reproducibility conditions. Consequently, the repeatability and reproducibility imprecision play different roles in the inference of results in clinical medicine. The purpose of the present review is to detail the properties of the imprecision calculated by duplicates of natural samples, to explain how it differs from imprecision calculated from single concentrations of control materials, and to elucidate what precautions need to be taken in case of bias, e.g. due to carry-over effects. |
| Databáze: | OpenAIRE |
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