Analyses of quality assessment studies using CD45 for gating lymphocytes for CD3(+)4(+)%

Area of Science:

• Clinical immunology
• Flow cytometry techniques
• Quality assessment in diagnostics

Background:

• Flow cytometry is crucial for immunophenotyping, particularly in monitoring HIV/AIDS.
• Accurate lymphocyte subset quantification (CD3, CD4, CD8) is vital for patient management.
• Quality assessment (QA) programs ensure laboratory reliability.

Purpose of the Study:

• To compare the performance of laboratories using CD45 gating versus those not using CD45 (non-CD45) in flow cytometry QA studies.
• To determine if CD45 gating impacts the accuracy and reproducibility of CD3(+)4(+)% and CD3(+)8(+)% measurements.

Main Methods:

• Analysis of data from 35 laboratories participating in the NIAID DAIDS Flow Cytometry QA Program over two years.
• Comparison of inter-laboratory and intra-laboratory variability for CD3(+)4(+)% and CD3(+)8(+)% between CD45 and non-CD45 laboratories.
• Inclusion of blood specimens from 62 donors, including 50 HIV-positive individuals.

Main Results:

• Non-CD45 laboratories had significantly higher rates of unacceptable inter-laboratory results for both CD3(+)4(+)% (5.6% vs 1.5%) and CD3(+)8(+)% (10.4% vs 5.0%).
• Intra-laboratory reproducibility was significantly worse in non-CD45 laboratories for CD3(+)8(+)% (14.5% vs 3.5%).
• These findings persisted despite non-CD45 laboratories having longer experience with three-color flow cytometry.

Conclusions:

• Utilizing CD45 gating in flow cytometry is associated with improved accuracy and reproducibility in lymphocyte subset analysis.
• Laboratories relying on a single CD3/CD4/CD8 tube without CD45 gating may compromise diagnostic precision.
• Implementing CD45 gating is recommended for enhancing the reliability of flow cytometry-based immunophenotyping.