ISAC XX Abstracts on Disc Presented by Purdue University Cytometry Laboratories

CD4+ T-CELL DETERMINATIONS WITH THE MULTI-PLATFORM METHOD - SOME CONTROL MEASURES

Ricardo Teixeira, Cristina Duarte, Ana Jesus, Fernanda Guerreiro, Graþa Lourenþo Laborat¾rio de Hematologia Hospital de Santa Maria Lisbon, Portugal

Abstract Number: 6171     Clinical Cytometry  –  Immunology and AIDS

In our routine practice, absolute CD4+ T cells in HIV-infected persons are measured in whole blood by the conventional multi-platform, three stage process. The white blood cell (WBC) count and the automated lymphocyte diferential are collected from an hematology analyzer (Coulter STKS). Immunophenotyping by flow cytometry (FC) is performed in an EPICS XL MCL after sample preparation with TQ-Prep (blood sample + CD45/CD4/CD8/CD3 + FlowCount). Beads are used to have a FC WBC count (CD45/SS öAll WBC gateö). Some internal control steps adopted are: 1.Validation of hematology test results is simultaneous with FC analysis. 2.10000 gated lymphocytes are counted in each sample. 3.WBC counts: Results from STKS and by FC must agree. (variation <10%). 4.Lymphocyte diferential: Results from STKS and by FC must agree (variation <10%) (ôautogate++ö). 5.Variations in 3 and 4 cannot produce a cumulative variation >10%. Corrective measures are frequently necessary and will be presented.

Keywords: flow cytometry; lymphocyte immunophenotyping; Quality control; HIV infection