How often should blood gas calibration verification by control media take place?

a. At least one level of control media should be analyzed every 8 hr.
b. At least two levels of control media should be analyzed every day.
c. At least two levels of control media should be analyzed every 8 hr.
d. At least two levels of control media should be analyzed every hour.

ANS: C
As a general recommendation, at least two levels of control media should be analyzed during every 8-hr shift.