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

Table 1 Laboratory Pima™ testing using venous blood

Phase I EDTA venous blood	Pima #1	Pima #2	Pima #3	Pima #4	All Pima DATA
N	53	61	59	58	100**
Range of CD4 counts*	2-1297	4-1217	5-1190	7-972	4.5-1235
Mean CD4 count*	349	334	354	317	318
%Similarity to Predicate ( *%SIM* Mean ± SD)	99.26 ± 5.34	99.15 ± 5.35	99.64 ± 6.42	97.17 ± 5.01	98.17 ± 4.57
%SIM CV ^#	5.38%	5.40%	6.44%	5.16%	4.66%
BA Bias* ± 1 STDev (PIMA - PLG) (95% CI of bias mean)	-14.38 ± 37.9 (-23.8 to -3.9)	-11.05 ± 42.4 (-21.9 to 0.19)	-13.6 ± 53.3 (-27.5 to 0.22)	-22.6 ± 40.3 (-33.2 to -12.0)	-17.3 ± 36.7 (-24.0 to -10.03)
BA 95% LOA*	-88.7 to 59.9	-94.1 to 72.1	-118.2 to 90.8	-101.6 to 56.4	-89.4 to 54.7

Statistical analyses across four Pima™ analysers tested in the laboratory during Phase 1 using a fixed 20 mm³ volume of manually pipetted EDTA venous blood and compared against predicate flow cytometry (PLG/CD4). 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
**The average Pima/CD4 value was used for comparison to predicate CD4 where more than two simultaneous Pima values were obtained.