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Controlling laboratory variables to improve precision and accuracy of CD4+ T-cell enumeration across flow cytometry methods

MSc (Med), Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, 2009 / This study assessed the effect that certain logistical and methodological factors in the
laboratory could have on influencing precision and accuracy of enumeration of CD4+ cells.
The efficacy of a new blood stabiliser to extend the window of CD4 testing, was also
evaluated.
CD4+ counts were derived using the 2-colour Pan-leucogating, 4-colour TetraONE and
MultiTEST/TruCount protocols on the EPICS-XL, FC-500 or FACSCalibur flow
cytometers. Statistical analyses included the paired-t-test, Spearman’s correlation and
Bland Altman comparisons.
The results showed that the reliability of CD4+ count results was heavily dependent on
how blood samples were handled prior to and after receipt into the laboratory and on how
samples were processed and analysed. The factors, motion, operator pipetting and analysis
skills, storage temperature, use of different protocols, different gating strategies and the use
of different flow cytometers, were found to influence accurate and precise enumeration of
CD4+ counts.

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/7975
Date13 April 2010
CreatorsMandy, Wilja Mirembe
Source SetsSouth African National ETD Portal
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Formatapplication/pdf

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