Sigma metrics in laboratory medicine: A call for harmonization.
Clin Chim Acta
; 532: 13-20, 2022 Jul 01.
Article
em En
| MEDLINE
| ID: mdl-35594921
ABSTRACT
BACKGROUND AND AIM:
Sigma metrics are applied in clinical laboratories to assess the quality of analytical processes. A parameter associated to a Sigma > 6 is considered "world class" whereas a Sigma < 3 is "poor" or "unacceptable". The aim of this retrospective study was to quantify the impact of different approaches for Sigma metrics calculation. MATERIAL ANDMETHODS:
Two IQC levels of 20 different parameters were evaluated for a 12-month period. Sigma metrics were calculated using the formula (allowable total error (TEa) (%) - bias (%))/(coefficient of variation (CV) (%)). Method precision was calculated monthly or annually. The bias was obtained from peer comparison program (PCP) or external quality assessment program (EQAP), and 9 different TEa sources were included.RESULTS:
There was a substantial monthly variation of Sigma metrics for all combinations, with a median variation of 32% (IQR, 25.6-41.3%). Variation across multiple analyzers and IQC levels were also observed. Furthermore, TEa source had the highest impact on Sigma calculation with proportions of Sigma > 6 ranging from 17.5% to 84.4%. The nature of bias was less decisive.CONCLUSION:
In absence of a clear consensus, we recommend that laboratories calculate Sigma metrics on a sufficiently long period of time (>6 months) and carefully evaluate the choice of TEa source.Palavras-chave
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Gestão da Qualidade Total
/
Laboratórios
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article