PMID- 34060592
OWN - NLM
STAT- MEDLINE
DCOM- 20211022
LR  - 20211022
IS  - 2576-9456 (Print)
IS  - 2475-7241 (Linking)
VI  - 6
IP  - 5
DP  - 2021 Sep 1
TI  - A Survey of Sigma Metrics across Three Academic Medical Centers.
PG  - 1264-1275
LID - 10.1093/jalm/jfab028 [doi]
AB  - BACKGROUND: Sigma metric calculations provide laboratories an objective means to 
      assess analytical method performance. Methods with higher sigma values are 
      desirable because they are more reliable and may use less frequent quality 
      control in order to maintain optimal performance. Sigma metrics can also serve as 
      a tool when comparing method performance across assay and manufacturer platforms. 
      METHODS: Sigma values were calculated for 28 common chemistry and 24 immunoassay 
      assays across 3 academic medical centers. Method imprecision and percent bias 
      relative to peer group means was tabulated from Bio-Rad quality control (QC) 
      data. Sigma values were calculated for each method using allowable total error 
      (TEa) from either the CLIA evaluation limits or desirable biological variation. 
      Average sigma values were generated for each site and graded as optimal: >6 
      sigma; good: 5-6 sigma; marginal: 3-5 sigma; or poor: <3 sigma. Analysis of NIST 
      SRM1950 standards for a subset of analytes allowed an estimation of absolute 
      bias. RESULTS: Clinical chemistry assays displayed similar method performance 
      across all 3 study sites. Immunoassays showed significant differences between 
      manufacturers, and a majority of assays failed to meet an optimal level of 
      performance. Different TEa values produced different sigma metrics with more 
      stringent TEa limits based on biological variation, resulting in poorer 
      performance estimates than the wider CLIA limits. Analysis of NIST standards 
      revealed similar performance. CONCLUSIONS: Sigma metrics are comparable for 
      chemistry but not immunoassay platforms. The selection of total allowable error 
      goals led to differences in sigma metrics.
CI  - (c) American Association for Clinical Chemistry 2021. All rights reserved. For 
      permissions, please email: journals.permissions@oup.com.
FAU - Feldhammer, Matthew
AU  - Feldhammer M
AD  - Department of Pathology and Laboratory Medicine, University of Florida College of 
      Medicine, Jacksonville, FL, USA.
FAU - Brown, Megan
AU  - Brown M
AD  - Department of Pathology and Laboratory Medicine, University of Florida College of 
      Medicine, Jacksonville, FL, USA.
FAU - Colby, Jennifer
AU  - Colby J
AD  - Department of Pathology, Microbiology and Immunology, Vanderbilt University 
      Medical Center, Nashville, TN, USA.
FAU - Bryksin, Janetta
AU  - Bryksin J
AD  - Department of Pathology and Laboratory Medicine, Emory University School of 
      Medicine, Atlanta, GA, USA.
FAU - Milstid, Bryan
AU  - Milstid B
AD  - University of Florida Health, Jacksonville, FL, USA.
FAU - Nichols, James H
AU  - Nichols JH
AD  - Department of Pathology, Microbiology and Immunology, Vanderbilt University 
      Medical Center, Nashville, TN, USA.
LA  - eng
PT  - Journal Article
PL  - England
TA  - J Appl Lab Med
JT  - The journal of applied laboratory medicine
JID - 101693884
SB  - IM
MH  - *Academic Medical Centers
MH  - Humans
MH  - Immunoassay
MH  - Quality Control
MH  - Reference Standards
MH  - *Total Quality Management
OTO - NOTNLM
OT  - clinical chemistry
OT  - immunoassay
OT  - method performance
OT  - sigma metrics
EDAT- 2021/06/02 06:00
MHDA- 2023/02/25 06:00
CRDT- 2021/06/01 08:47
PHST- 2020/12/29 00:00 [received]
PHST- 2021/03/22 00:00 [accepted]
PHST- 2021/06/02 06:00 [pubmed]
PHST- 2023/02/25 06:00 [medline]
PHST- 2021/06/01 08:47 [entrez]
AID - 6290665 [pii]
AID - 10.1093/jalm/jfab028 [doi]
PST - ppublish
SO  - J Appl Lab Med. 2021 Sep 1;6(5):1264-1275. doi: 10.1093/jalm/jfab028.