PMID- 35594921
OWN - NLM
STAT- MEDLINE
DCOM- 20220621
LR  - 20220621
IS  - 1873-3492 (Electronic)
IS  - 0009-8981 (Linking)
VI  - 532
DP  - 2022 Jul 1
TI  - Sigma metrics in laboratory medicine: A call for harmonization.
PG  - 13-20
LID - S0009-8981(22)01146-9 [pii]
LID - 10.1016/j.cca.2022.05.012 [doi]
AB  - 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 AND METHODS: 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.
CI  - Copyright (c) 2022 Elsevier B.V. All rights reserved.
FAU - Wauthier, Loris
AU  - Wauthier L
AD  - Department of Laboratory Medicine, Clinique St-Luc Bouge, Namur, Belgium. 
      Electronic address: loris.wauthier@icloud.com.
FAU - Di Chiaro, Laura
AU  - Di Chiaro L
AD  - Department of Laboratory Medicine, Clinique St-Luc Bouge, Namur, Belgium.
FAU - Favresse, Julien
AU  - Favresse J
AD  - Department of Laboratory Medicine, Clinique St-Luc Bouge, Namur, Belgium; 
      Department of Pharmacy, Namur Research Institute for LIfe Sciences, University of 
      Namur, Namur, Belgium. Electronic address: julien.favresse@slbo.be.
LA  - eng
PT  - Journal Article
DEP - 20220517
PL  - Netherlands
TA  - Clin Chim Acta
JT  - Clinica chimica acta; international journal of clinical chemistry
JID - 1302422
SB  - IM
MH  - Bias
MH  - Humans
MH  - *Laboratories
MH  - Research Design
MH  - Retrospective Studies
MH  - *Total Quality Management/methods
OTO - NOTNLM
OT  - Analytical performance specification
OT  - Bias
OT  - Imprecision
OT  - Quality controls
OT  - Sigma metrics
OT  - Total error
EDAT- 2022/05/21 06:00
MHDA- 2022/06/22 06:00
CRDT- 2022/05/20 19:23
PHST- 2022/04/07 00:00 [received]
PHST- 2022/04/27 00:00 [revised]
PHST- 2022/05/13 00:00 [accepted]
PHST- 2022/05/21 06:00 [pubmed]
PHST- 2022/06/22 06:00 [medline]
PHST- 2022/05/20 19:23 [entrez]
AID - S0009-8981(22)01146-9 [pii]
AID - 10.1016/j.cca.2022.05.012 [doi]
PST - ppublish
SO  - Clin Chim Acta. 2022 Jul 1;532:13-20. doi: 10.1016/j.cca.2022.05.012. Epub 2022 
      May 17.