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The Immunology Quality Assessment Proficiency Testing Program for CD3⁺4⁺ and CD3⁺8⁺ lymphocyte subsets: a ten year
J Bainbridge1, C L Wilkening2, W Rountree1
1Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC, USA.
Insights
Proficiency in T-cell subset measurements improved significantly over ten years in North American laboratories. Single-platform technology generally offered greater precision and accuracy in flow cytometry assessments.
Area of Science:
- Immunology
- Clinical Laboratory Science
- Flow Cytometry
Background:
- The National Institute of Allergy and Infectious Diseases Division of AIDS (NIAID DAIDS) established the Immunology Quality Assessment (IQA) Program to ensure consistent T-cell subset measurements in HIV clinical trials.
- Variability in interlaboratory and intralaboratory measurements can impact the reliability of HIV clinical trial data.
Purpose of the Study:
- To analyze ten years of T-cell subset measurement data from the IQA Program (2003-2012).
- To assess trends in laboratory proficiency, interlaboratory agreement (accuracy), and intralaboratory variability (precision).
- To evaluate the impact of single-platform technology (SPT) versus dual-platform technology (DPT) on measurement performance.
Main Methods:
- Longitudinal analysis using mixed-effects models to examine trends over time.
- Evaluation of accuracy and precision based on repeated measures variance and fixed/random effects.
- Comparison of performance metrics between SPT and DPT systems.
Main Results:
- A significant increase in the accuracy of T-cell subset measurements was observed over the ten-year period for both SPT and DPT (p<0.001).
- Single-platform technology demonstrated greater precision (p<0.001) and accuracy for CD3(+)4(+)% and CD3(+)8(+)% assessments (p<0.05 and p<0.001, respectively).
- Dual-platform technology showed potential for increased accuracy in specific cases, indicated by interlaboratory random effects variance.
Conclusions:
- Overall laboratory proficiency in T-cell subset immunophenotyping has improved significantly.
- Differences in performance exist between SPT and DPT, with SPT generally offering superior precision and accuracy.
- Continued monitoring and quality assessment are crucial for maintaining reliable HIV clinical trial data.
Abstract:
Since 1999, the National Institute of Allergy and Infectious Diseases Division of AIDS (NIAID DAIDS) has funded the Immunology Quality Assessment (IQA) Program with the goal of assessing proficiency in basic lymphocyte subset immunophenotyping for each North American laboratory supporting the NIAID DAIDS HIV clinical trial networks. Further, the purpose of this program is to facilitate an increase in the consistency of interlaboratory T-cell subset measurement (CD3(+)4(+)/CD3(+)8(+) percentages and absolute counts) and likewise, a decrease in intralaboratory variability. IQA T-cell subset measurement proficiency testing was performed over a ten-year period (January 2003-July 2012), and the results were analyzed via longitudinal analysis using mixed effects models. The goal of this analysis was to describe how a typical laboratory (a statistical modeling construct) participating in the IQA Program performed over time. Specifically, these models were utilized to examine trends in interlaboratory agreement, as well as successful passing of proficiency testing. Intralaboratory variability (i.e., precision) was determined by the repeated measures variance, while fixed and random effects were taken into account for changes in interlaboratory agreement (i.e., accuracy) over time. A flow cytometer (single-platform technology, SPT) or a flow cytometer/hematology analyzer (dual-platform technology, DPT) was also examined as a factor for accuracy and precision. The principal finding of this analysis was a significant (p<0.001) increase in accuracy of T-cell subset measurements over time, regardless of technology type (SPT or DPT). Greater precision was found in SPT measurements of all T-cell subset measurements (p<0.001), as well as greater accuracy of SPT on CD3(+)4(+)% and CD3(+)8(+)% assessments (p<0.05 and p<0.001, respectively). However, the interlaboratory random effects variance in DPT results indicates that for some cases DPT can have increased accuracy compared to SPT. Overall, these findings demonstrate that proficiency in and among IQA laboratories have, in general, improved over time and that platform type differences in performance do exist.
