Performance evaluation of the Pima™ point-of-care CD4 analyser using capillary blood sampling in field tests in South Africa

Table 2 Hospital antenatal Pima™ field testing using capillary blood

Phase II	Laboratory Pima™ vs. Predicate			Clinic Pima™ vs. Predicate
	Venous EDTA blood			Capillary blood
	*Pima #1	*Pima #4	Mean Pima #1 and #4*	Pima #3	Pima #2	All values
N	91	91	91	43	34	77
Range of CD4 counts*	32 - 1186	23 - 1299	28 - 1243	28 - 1092	50 - 1056	28 - 1092
Mean CD4 count*(median)	385.6 (341.0)	399.8 (357.0)	392.7 (347.0)	335.0 (405.0)	350.2 (290.0)	380.8 (329.0)
%Similarity to Predicate ( *%SIM* Mean ± SD)	96.9% ± 7.89	98.3% ± 7.05	97.6% ± 6.5	98.6% ± 28.45	96.1% ± 16.8	98.7 ± 23.02
%SIM CV ^#	8.1%	7.2%	6.7%	28.8%	17.6%	23.3
BA bias* ± 1 STDev (PIMA - PLG) (95% CI of bias mean)	-26.6 ± 73.3 (-41.9 to -11.4)	-12.4 ± 68.1 (-26.6 to 1.8)	-19.6 ± 66.1 (-33.3 to -5.8)	-31.79 ± 213.1 (-97.4 to 33.8)	-45.5 ± 127.7 (-90.1 to -1.0)	-37.9 ± 179.5 (-78.3 to 2.87)
BA 95% LOA*	-170.4 to 117.1	-145.8 to 121.0	-149.1 to 110.0	-147.4 to 385.9	-295.8 to 204.6	-389.1 to 309.8

Statistical analysis of Pima™ analysers field-tested in a hospital-based antenatal HCT clinic (N = 77) and in the laboratory (N = 91) during Phase II testing versus predicate reporting. A direct comparison of Pima performance using matched venous vs. capillary blood samples is shown. All values, with the exception of N, refer to CD4 cell counts in cells/mm³. BA = Bland-Altman statistical analysis. LOA = limits of agreement. #Precision of Pima™ to Predicate method expressed as %SIM CV.
*cells/mm³