Department of Army lymphocyte immunophenotyping quality assurance program.

Area of Science:

• Clinical immunology
• Flow cytometry
• Quality assurance in laboratory medicine

Background:

• The human immunodeficiency virus (HIV) epidemic necessitates accurate lymphocyte immunophenotyping for patient management.
• The Department of the Army established a quality assurance program for lymphocyte immunophenotyping in 1986.
• Proficiency testing is crucial for assessing the precision and reproducibility of lymphocyte subset analysis.

Purpose of the Study:

• To evaluate the precision and reproducibility of lymphocyte subset determinations within a multicenter Army program.
• To assess the performance of lymphocyte immunophenotyping across various Army laboratories.
• To compare the variability of Army laboratories with external studies.

Main Methods:

• Implementation of a monthly proficiency testing program for lymphocyte immunophenotyping.
• Analysis of cumulative average standard deviation and coefficient of variation for multiple lymphocyte subsets (CD2, CD3, CD4, CD8, CD8*CD3, CD19/20, NK cells).
• Comparison of Army laboratory results with data from 49 external laboratories.

Main Results:

• Low interlaboratory variability was observed within the Army program.
• Cumulative average coefficients of variation for key lymphocyte subsets ranged from 3.9% to 26.5%.
• Army laboratories demonstrated approximately half the interlaboratory variability compared to other multicenter studies.

Conclusions:

• The Army's multicenter lymphocyte immunophenotyping quality assurance program achieved high precision and reproducibility.
• The established proficiency testing program effectively monitors and ensures the quality of lymphocyte subset analysis.
• The findings support the reliability of flow cytometry-derived lymphocyte subset values in clinical management.