Lab Med Qual Assur.  2022 Mar;44(1):48-54. 10.15263/jlmqa.2022.44.1.48.

Application of Geometric Mean Criteria for AntiBlood Group Antibody Proficiency Testing in the Korean External Quality Assurance Program

• Yang JJ
• Youk HJ
• Chung Y
• Kim H
• Hwang SH
• Oh HB
• Ko DH

• KMID: 2527805
• DOI: http://doi.org/10.15263/jlmqa.2022.44.1.48

Abstract

Background
The geometric mean criteria (GC) is an alternative for assessing proficiency testing (PT) acceptability. A recent study applied GC to the PT results provided by the College of American Pathologists. We assessed the feasibility of using GC for anti-blood group antibody titration testing (ABT) in the Korean PT program.
Methods
The results of the ABT performed in 2019 were reviewed using GC. GC was calculated as geometric mean (GM)±multiples of geometric standard deviation (GSD). The number of acceptable results obtained using GC was compared to that of the conventional mode criteria (MC, mode±1 second). Only the results with 30 or more peer group responses were included in the analyses.
Results
A total of 27 PT results (anti-A: 13, anti-B: 14) were analyzed. The acceptable proportions from MC were 82.9%–100.0% for anti-A and 76.2%– 100.0% for anti-B. The GC criteria yielded acceptable results of 46.9%–97.6% (1 GSD), 88.6%–100.0% (2 GSD), and 97.3%–100.0% (3 GSD) for anti-A. For anti-B, 1 GSD, 2 GSD, and 3 GSD criteria resulted in 44.7%–90.6%, 90.6%– 100.0%, and 97.4%–100.0%, respectively. In general, acceptable results using MC were found to be distributed between 1 GSD and 2 GSD.
Conclusions
The GC can be used as an alternative assessment criterion with a more robust statistical rationale. While conventional MC struggles with representing the central tendency of data, GC provide better visualization of the central tendency.

Keyword

Laboratory proficiency testing; Geometric mean; Mode; Accep tability