Retrospection of Anti–Blood Group Antibody Proficiency Testing Data Using the Geometric Mean and Standard Deviation

• Published in: American journal of clinical pathology Vol. 153; no. 4; pp. 530 - 536
• Main Authors: Yang, John Jeongseok, Chung, Yousun, Kim, Hyungsuk, Ko, Dae-Hyun, Hwang, Sang-Hyun, Oh, Heung-Bum
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 09-03-2020
• Subjects: Analysis; Antibodies; Blood; Blood groups; Dispersion measures (Statistics); Hematology; Medical examination; Medical research; Medical statistics; Medicine, Experimental; Methods; Standard deviation; Statistical analysis; Statistics; Viral antibodies; South Korea; Standard deviation; Geometric mean; Anti–blood group antibody; Proficiency testing; Retrospection
• ISSN: 0002-9173; 1943-7722
• DOI: 10.1093/ajcp/aqz187

Abstract
Objectives
We reanalyzed the data from proficiency testing (PT) to assess the effect of the geometric mean in the statistical analysis of immunohematologic data.
Methods
Using the five most recent anti–blood group antibody titer participant summary results, the geometric mean (GM) ±2 × geometric standard deviation (GSD) was used as the comparative consensus criterion to mode ±2 titers.
Results
Using the PT evaluation criterion of mode ±2 titers, the mean percentages of participants with acceptable results were 97.5% and 97.8% for anti-A and anti-D, respectively. When applying GM ±2 GSD, the mean percentages of acceptable results were 96.1% (anti-A) and 96.1% (anti-D). The percentages of responses included in each consensus criterion were lower using GM ±2 GSD, with a few exceptions.
Conclusions
Geometric means are more robust and precise in visualizing the central tendency. This method can improve the statistical robustness of PT evaluations.