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A North American multilaboratory study of CD4 counts using flow cytometric panleukogating (PLG): A NIAID‐DAIDS Immunology Quality Assessment Program Study
Author(s) -
Denny Thomas N.,
Gelman Rebecca,
Bergeron Michele,
Landay Alan,
Lam Lee,
Louzao Raul,
Mandy Frank F.,
Schmitz John,
Spira Thomas,
Wilkening Cindy,
Glencross Deborah K.
Publication year - 2008
Publication title -
cytometry part b: clinical cytometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 61
eISSN - 1552-4957
pISSN - 1552-4949
DOI - 10.1002/cyto.b.20417
Subject(s) - predicate (mathematical logic) , external quality assessment , medicine , human immunodeficiency virus (hiv) , quality assessment , immunology , statistics , mathematics , computer science , pathology , programming language
Background The global HIV/AIDS pandemic and guidelines for initiating anti‐retroviral therapy (ART) and opportunistic infection prophylaxis demand affordable, reliable, and accurate CD4 testing. A simple innovative approach applicable to existing technology that has been successfully applied in resource‐challenged settings, PanLeukogated CD4 (PLG), could offer solutions for cost saving and improved precision. Methods Day‐old whole blood from 99 HIV+ donors was simultaneously studied in five North‐American laboratories to compare the performance of their predicate methods with the dual‐platform PLG method. The predicate technology included varying 4‐color CD45/CD3/CD4/CD8 protocols on different flow cytometers. Each laboratory also assayed eight replicate specimens of day‐old blood from 10 to 14 local donors. Bias and precision of predicate and PLG methods was studied between‐ and within‐participating laboratories. Results Significantly ( P < 0.0001) improved between‐laboratory precision/coefficient of variation (CV%) was noted using the PLG method (overall median 9.3% vs. predicate median CV 13.1%). Within‐laboratory precision was also significantly ( P < 0.0001) better overall using PLG (median 4.6% vs . predicate median CV 6.2%) and in 3 of the 5 laboratories. PLG counts tended to be 11% smaller than predicate methods ( P < 0.0001) for shipped (median of predicate—PLG = 31) and local specimens (median of predicate—PLG = 23), both overall and in 4 of 5 laboratories (median decreases of 4, 16, 20, and 21% in shipped specimens); the other laboratory had a median increase of 5%. Conclusion Laboratories using predicate CD4 methods similar to those in this study could improve their between‐laboratory and their within‐laboratory precision, and reduce costs, by switching to the PLG method after adequate training, if a change (usually, a decrease) in CD4 counts is acceptable to their health systems. © 2008 Clinical Cytometry Society