Table 1. Mean and Median Bias Analysis of Pima Capillary and Venous Measurements.

Comparison	Reference method* (cells/µl)	Number of pairs (%)	Mean Bias (95%CI)	Median Bias (IQR)	P-value**
Pima CD4 Capillary	Overall	176	−66.3(−83.4, −49.2)	−41.0(−105.0, 4.5)	<0.001
	0–250	27	−10.8(−27.3, 5.6)	−6.0 (−32.0, 11.0)	0.198
	250–500	90	−47.3(−62.2, −32.5)	−40.5 (−76, −5.0)	<0.001
	>500	59	−120.6 (−162.8, −78.4)	−107.0 (−197.0, −10.0)	<0.001
Pima CD4 Venous	Overall	206	−68.5 (−79.6, −57.4)	−54.0 (−95.0, −17.0)	<0.001
	0–250	35	13.6 (2.5, 24.7)	−16.0 (−35.0, −1.0)	0.020
	250–500	107	−54.6 (−64.5, −44.7)	−53.0 (−79.0, −23.0)	<0.001
	>500	64	−121.7 (−147.9, −95.4)	−93.5 (−167.5, −64.5)	<0.001

^*BD FACSCalibur.

^** P-value using Wilcoxon Signed Rank Test.

CI = confidence interval, CD4 = CD4+ T cell count (cells/µL).