Table 2 In vitro CO measures (ppm) provided by B&K and PiCO+ on four standards

5 ppm

5.1 (0.1)

6.7 (0.4)

<0.01

9.9 ppm

10. 00 (0.1)

12. 0 (0.9)

<0.05

20 ppm

19. 00 (0.1)

18. 5 (0.6)

0.59

50 ppm

47. 9 (0.2)

47. 0 (1.0)

0.28