Document 0463
 DOCN  M9650463
 TI    Standardization of absolute CD4+ lymphocyte counts across laboratories:
       an evaluation of the Ortho CytoronAbsolute flow cytometry system on
       normal donors.
 DT    9605
 AU    Connelly MC; Knight M; Giorgi JV; Kagan J; Landay AL; Parker JW; Page E;
       Spino C; Wilkening C; Mercolino TJ; Immunocytometry Research and
       Development, Ortho Diagnostic; Systems, Raritan, New Jersey 08869, USA.
 SO    Cytometry. 1995 Sep 15;22(3):200-10. Unique Identifier : AIDSLINE
       MED/96106603
 AB    The Ortho CytoronAbsolute is a flow cytometer designed to provide direct
       absolute counts of lymphocytes and their subsets from a single
       instrument. This study was designed to determine the performance of four
       geographically separated CytoronAbsolute instruments using 24-h-old,
       shipped, whole blood samples and to compare the results obtained on the
       CytoronAbsolute to those obtained using combinations of hematology
       instruments and other flow cytometers. The absolute count feature of the
       CytoronAbsolutes located at the four sites were cross calibrated and
       gave across-site coefficients of variation (CVs) of <4.0% for absolute
       count and 8.2% for absolute lymphocyte count. The calibration was stable
       for at least 2 months. Absolute lymphocyte counts and lymphocyte
       percentage immunophenotypes were determined on blood from 50 healthy
       human immunodeficiency virus (HIV)-seronegative donors. There were no
       significant site-to-site differences (each P > .05) in CD3+/CD4+
       absolute lymphocyte counts determined on the CytoronAbsolute. In
       contrast, there was a significant site-to-site difference (P < .001)
       between sites 2 and 3 and sites 3 and 4 in the absolute CD3+/CD4+
       lymphocyte counts determined via the conventional method of combining a
       flow cytometry-derived percentage with a hematology instrument-derived
       lymphocyte count. There was no significant difference (P = .388) in
       CD3+/CD4+ lymphocyte percent determinations between the CytoronAbsolute
       and the FACScan or Profile II flow cytometers used in this study. These
       results demonstrate that different operators can cross calibrate
       CytoronAbsolutes for absolute CD3+/CD4+ lymphocyte subset
       determinations, even over large geographic distances.
 DE    Calibration  CD4 Lymphocyte Count/*METHODS  Evaluation Studies  Flow
       Cytometry/*INSTRUMENTATION  Human  Reproducibility of Results  Tissue
       Donors  JOURNAL ARTICLE

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