Table 2.

Comparative performance of capillary and venous CD4+ T-lymphocyte counts on Pima™ POC and FACSCalibur™ by laboratory technicians and lay-counselors in Western Kenya.

	Statistic	FACS Calibur Venous CD4 Count	FACS Calibur Capillary CD4 Count	PIMA Lab Venous CD4 Count	PIMA Lab Capillary CD4 Count	PIMA lay-counselors Venous CD4 Count	PIMA lay-counselors Capillary CD4 Count
FACS Calibur Venous CD4 Count	Accuracy (Ca)	1.0	0.993	0.950	0.953	0.915	0.941
	Precision (r)	1.0	0.968	0.960	0.963	0.954	0.958
	CCC (rc)	1.0	0.962 0.947, 0.972	0.912 0.885, 0.932	0.918 0.893, 0.937	0.873 0.838, 0.900	0.902 0.873, 0.925
	Bias	0.0	−26.9 −37.5, −16.4	−65.7 −78.4, −53.0	−63.0 −75.3, −50.6	−86.4 −100.4, −72.4	−71.2 −82.3, −58.2
FACS Calibur Capillary CD4 Count	Accuracy (Ca)		1.0	0.979	0.981	0.953	0.973
	Precision (r)		1.0	0.944	0.961	0.947	0.956
	CCC (rc)		1.0	0.924 0.898, 0.943	0.943 0.924, 0.957	0.902 0.872, 0.926	0.930 0.908, 0.948
	Bias		0.0	−38.8 −52.2, −25.3	−36.0 −47.5, −24.6	−59.5 −73.0, −45.9	−44.3 −56.5, −32.1
PIMA Lab Venous CD4 Count	Accuracy (Ca)			1.0	0.9999	0.994	0.9996
	Precision (r)			1.0	0.963	0.956	0.956
	CCC (rc)			1.0	0.963 0.949, 0.973	0.950 0.932, 0.964	0.955 0.939, 0.968
	Bias			0.0	2.7 −6.9, 12.4	−20.7 −31.2, −10.3	−5.5 −16.0, 5.0
PIMA Lab Capillary CD4 Count	Accuracy (Ca)				1.0	0.993	0.999
	Precision (r)				1.0	0.963	0.970
	CCC (rc)				1.0	0.956 0.939, 0.968	0.970 0.958, 0.978
	Bias				0.0	−23.5 −33.1, −13.9	−8.3 −16.9, 0.4
PIMA lay-counselors Venous CD4 Count	Accuracy (Ca)					1.0	0.997
	Precision (r)					1.0	0.957
	CCC (rc)					1.0	0.954 0.937, 0.967
	Bias					0.0	15.2 5.0, 25.4
PIMA lay-counselors Capillary CD4 Count	Accuracy (Ca)						1.0
	Precision (r)						1.0
	CCC (rc)						1.0
	Bias						0.0

Note to Table 2: CCC: concordance correlation coefficient. Bias (in units of cells/μl) was estimated using the Bland-Altman method. All comparisons to FACSCalibur™venous for CD4 counts are comparing to the reference. Comparisons for non-FACSCalibur™ venous have neither as a reference.