The Immunology Quality Assessment Proficiency Testing Program for CD3⁺4⁺ and CD3⁺8⁺ lymphocyte subsets: a ten year review via longitudinal mixed effects modeling.

Thumbnail Image



Journal Title

Journal ISSN

Volume Title

Repository Usage Stats


Citation Stats


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.





Published Version (Please cite this version)


Publication Info

Bainbridge, J, CL Wilkening, W Rountree, R Louzao, J Wong, N Perza, A Garcia, TN Denny, et al. (2014). The Immunology Quality Assessment Proficiency Testing Program for CD3⁺4⁺ and CD3⁺8⁺ lymphocyte subsets: a ten year review via longitudinal mixed effects modeling. Journal of Immunological Methods, 409. pp. 82–90. 10.1016/j.jim.2014.05.017 Retrieved from

This is constructed from limited available data and may be imprecise. To cite this article, please review & use the official citation provided by the journal.



Thomas Norton Denny

Professor in Medicine

Thomas N. Denny, MSc, M.Phil, is the Chief Operating Officer of the Duke Human Vaccine Institute (DHVI), Associate Dean for Duke Research and Discovery @RTP, and a Professor of Medicine in the Department of Medicine at Duke University Medical Center. He is also an Affiliate Member of the Duke Global Health Institute. Previously, he served on the Health Sector Advisory Council of the Duke University Fuquay School of Business. Prior to joining Duke, he was an Associate Professor of Pathology, Laboratory Medicine and Pediatrics, Associate Professor of Preventive Medicine and Community Health and Assistant Dean for Research in Health Policy at the New Jersey Medical School, Newark, New Jersey. He has served on numerous committees for the NIH over the last two decades and currently is the principal investigator of an NIH portfolio in excess of 65 million dollars. Mr. Denny was a 2002-2003 Robert Wood Johnson Foundation Health Policy Fellow at the Institute of Medicine of the National Academies (IOM). As a fellow, he served on the US Senate Health, Education, Labor and Pensions Committee with legislation/policy responsibilities in global AIDS, bioterrorism, clinical trials/human subject protection and vaccine related-issues.

As the Chief Operating Officer of the DHVI, Mr. Denny has senior oversight of the DHVI research portfolio and the units/teams that support the DHVI mission. He has extensive international experience and previously was a consultant to the U.S. Centers for Disease Control and Prevention (CDC) for the President’s Emergency Plan for AIDS Relief (PEPFAR) project to oversee the development of an HIV and Public Health Center of Excellence laboratory network in Guyana. In September 2004, the IOM appointed him as a consultant to their Board on Global Health Committee studying the options for overseas placement of U.S. health professionals and the development of an assessment plan for activities related to the 2003 PEPFAR legislative act. In the 1980s, Mr. Denny helped establish a small laboratory in the Republic of Kalmykia (former Soviet Union) to improve the care of children with HIV/AIDS and served as a Board Member of the Children of Chernobyl Relief Fund Foundation. In 2005, Mr. Denny was named a consulting medical/scientific officer to the WHO Global AIDS Program in Geneva. He has also served as program reviewers for the governments of the Netherlands and South Africa as well as an advisor to several U.S. biotech companies. He currently serves as the Chair of the Scientific Advisory Board for Grid Biosciences.

Mr. Denny has authored and co-authored more than 200 peer-reviewed papers and serves on the editorial board of Communications in Cytometry and Journal of Clinical Virology. He holds an M.Sc in Molecular and Biomedical Immunology from the University of East London and a degree in Medical Law (M.Phil) from the Institute of Law and Ethics in Medicine, School of Law, University of Glasgow. In 1991, he completed a course of study in Strategic Management at The Wharton School, University of Pennsylvania. In 1993, he completed the Program for Advanced Training in Biomedical Research Management at Harvard School of Public Health. In December 2005, he was inducted as a Fellow into the College of Physicians of Philadelphia, the oldest medical society in the US.

While living in New Jersey, Mr. Denny was active in his community, gaining additional experience from two publicly elected positions. In 2000, Mr. Denny was selected by the New Jersey League of Municipalities to Chair the New Jersey Community Mental Health Citizens’ Advisory Board and Mental Health Planning Council as a gubernatorial appointment.

Unless otherwise indicated, scholarly articles published by Duke faculty members are made available here with a CC-BY-NC (Creative Commons Attribution Non-Commercial) license, as enabled by the Duke Open Access Policy. If you wish to use the materials in ways not already permitted under CC-BY-NC, please consult the copyright owner. Other materials are made available here through the author’s grant of a non-exclusive license to make their work openly accessible.