title: Inter- and intrainstitutional evaluation of automated volumetric capillary cytometry for the quantitation of CD4- and CD8-positive T lymphocytes in the peripheral blood of persons infected with human immunodeficiency virus. Site Investigators and the NIAID New CD4 Technologies Focus Group.
abstract: Volumetric capillary cytometry (VCC) is a new technology that involves the detection and enumeration of dually fluorochrome-labeled cells in a precise volume. We compared the accuracy and precision of VCC with the accuracy and precision of flow cytometry and hematology (F&H) for the measurement of the absolute numbers of CD4 and CD8 T cells in the whole blood of patients infected with human immunodeficiency virus. Five laboratories, each with a different F&H system and certified by the National institute of Allergy and Infectious Diseases flow cytometry proficiency testing program, were shipped aliquots of the same samples from a central site in addition to procuring samples locally. In general, the VCC technology generated CD4 and CD8 T-cell counts which were lower than those obtained with F&H. Intralaboratory variability of replicate CD4 T-cell determinations was similar for both technologies except in the local samples with CD4 counts less than 200/microliters, where the VCC variability was higher than the F&H variability. Interlaboratory variability on replicate CD4 T-cell counts made by VCC was significantly less than that when counts were made by F&H. The VCC instrument has automated CD4 and CD8 T-cell enumeration in whole blood and has consolidated the process to a single platform. Its performance in this evaluation indicates that it may represent a viable alternative to F&H for obtaining absolute T-cell subset counts.
authors.affiliation: Children's Memorial Hospital, Northwestern University Medical School, Chicago, Illinois 60614, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: O'Gorman
authors.forename: R
authors.initials: R
authors.lastname: Gelman
mesh_terms: D000704:Analysis of Variance; D018791:CD4 Lymphocyte Count / Q000295:instrumentation / Q000379:methods*; D018414:CD8-Positive T-Lymphocytes; D003592:Cytophotometry / Q000295:instrumentation / Q000379:methods*; D005069:Evaluation Studies as Topic; D005434:Flow Cytometry; D015658:HIV Infections / Q000097:blood* / Q000276:immunology; D006405:Hematology; D006801:Humans; D018655:Lymphocyte Count / Q000295:instrumentation / Q000379:methods*