Lifescan OneTouch Basic Basic Blood Glucose Monitoring System Owner's Booklet page 52

recently, the blood glucose level from a
fingerstick can be up to 70 mg/dL
higher than blood drawn from a vein
7
(venous sample) used for a lab test.
Therefore it is best to fast for four to
eight hours before doing comparison
tests. Factors such as the amount of
red blood cells in the blood (a high or
low hematocrit) or the loss of body
fluid (severe dehydration) may also
give a meter result different from a
laboratory result.
44