Comparison of two alternative methods for CD4+ T-cell determination (Coulter manual CD4 count and CyFlow) against standard dual platform flow cytometry in Uganda.
BACKGROUND
In this study we evaluated alternative CD4(+) T-cell counting methods in clients of a PMTCT Programme in rural Uganda.


METHODS
The Coulter Manual CD4 Count method for CD4(+) T-cell enumeration (Cyto-Spheres) and an automated method (volumetric, single-platform flow cytometry; CyFlow) were compared with a standard, dual-platform flow cytometry protocol (DPFC, FACScan).


RESULTS
Correlation and precision of agreement were higher for the CyFlow method (r = 0.929 and eta = 0.08) when compared to DPFC than for the Cyto-Spheres method (r = 0.725 and eta = 0.3). Multiple linear regression analysis showed that CD4(+) cell counts by the CyFlow method were a stronger predictor for results of DPFC than those of the Cyto-Spheres method (r(2) = 0.864 and r(2) = 0.552, respectively). When compared to DPFC the CyFlow method generated higher CD4(+) cell counts than the Cyto-Spheres method, as expressed by a higher median and mean difference (+70 and +90 cells for CyFlow, +28 and -1.4 cells for Cyto-Spheres).


CONCLUSIONS
Both, the manual Cyto-Spheres method and the CyFlow method can be used for the enumeration of CD4(+) cells in resource-limited settings. Under supervised conditions, the CyFlow method produced results more consistent with the reference method than the Cyto-Spheres method.
German Technical Cooperation (GTZ), PMTCT Project Berlin. pmtct.gtz3@t-online.de
Heiko
H
Karcher
Dankmar
D
Böhning
Robert
R
Downing
Silver
S
Mashate
Gundel
G
Harms
D000465:Algorithms; D018791:CD4 Lymphocyte Count / Q000191:economics / Q000295:instrumentation / Q000379:methods*; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D007958:Leukocyte Count / Q000191:economics / Q000295:instrumentation / Q000379:methods; D016014:Linear Models; D008297:Male; D012372:ROC Curve; D015203:Reproducibility of Results; D014454:Uganda