Table 5: Estimated total precision for between–laboratory variability.

Process Control BCW MED SFG
Mean %CV(UL) Mean %CV(UL) Mean %CV(UL)
CD4 Low 137.97 5.23 (6.39) 138.77 5.79 (7.06) 140.07 5.12 (6.24)
CD4 Normal 844.67 2.87 (3.50) 844 2.49 (3.04) 856.30 1.88 (2.29)
- Mean SD(UL)/
%CV(UL)
Mean SD(UL)/
%CV(UL)
Mean SD(UL)/
%CV(UL)
%CD4 Low 12.65 0.62 (0.79) 12.85 0.59 (0.76) 12.76 0.56 (0.72)
%CD4 Normal 43.96 1.82 (2.22) 44.08 1.79 (2.19) 44.42 1.59 (1.93)
- Mean %CV(UL) Mean %CV(UL) Mean %CV(UL)
Hb Level 1 7.20 3.11 (3.79) 7.26 2.18 (2.66) 7.23 2.83 (3.46)
Hb Level 2 12.93 1.52 (1.86) 12.94 1.32 (1.61) 12.94 1.71 (2.08)
Hb Level 3 17.11 1.34 (1.64) 17.06 1.30 (1.58) 17.20 1.02 (1.24)

%CV= Percent coefficient of variation; UL= Upper limit; BCW= BloodCenter of Wisconsin; MED= BD Biosciences MedLab; SFG= San Francisco General Hospital.