External quality control study of lymphocyte subset tests in Japan

Area of Science:

• Immunology
• Clinical Laboratory Science
• Medical Diagnostics

Background:

• Lymphocyte subset analysis is critical for diagnosing and monitoring various immunodeficiencies and autoimmune diseases.
• External quality assurance (EQA) programs are essential for ensuring the accuracy and comparability of laboratory test results.

Purpose of the Study:

• To evaluate the external quality assurance of lymphocyte subset testing across medical laboratories in Japan.
• To identify factors contributing to variability in lymphocyte subset test results.

Main Methods:

• Analysis of data from an external quality assurance program for lymphocyte subset testing in Japan.
• Assessment of variability in different lymphocyte markers, including CD3, CD19/20, NK markers, CD4, and CD8.

Main Results:

• Significant variability was observed in lymphocyte subset values among Japanese medical laboratories.
• CD19/20 and NK markers showed wider variation compared to CD3, CD4, and CD8.
• Lower coefficients of variation (CV) were noted in commercial laboratories and when using specific reagents and instruments (Ortho-Clinical Diagnostics).
• Reduced cell washing times and the use of self-made lytic agents were associated with lower CV in some instances.

Conclusions:

• External quality assurance highlights substantial variability in lymphocyte subset testing in Japan.
• Standardization of methods, reagents, and instruments is recommended to improve the consistency of lymphocyte subset analysis.
• Further investigation into the impact of pre-analytical factors like cell washing and lysis methods on test variability is warranted.