34
You may still have a variation from the result because blood
glucose levels can change significantly over short periods of time,
especially if you have recently eaten , exercised, taken medication,
or experienced stress*
3
. In addition, if you have eaten recently, the
blood glucose level from a finger prick can be up to 70 mg/dL higher
than blood drawn from a vein (venous sample) used for a lab test.*
4
Therefore, it is best to fast for 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 (dehydration) may
also cause a meter result to be different from a laboratory result.
*3: Surwit, R.S., and Feinglos, M.N.: Diabetes Forecast (1988), April, 49-51.
*4: Sacks, D.B.: “Carbohydrates. “ Burtis, C.A., and Ashwood, E.R.( ed.),
Tietz Textbook of Clinical Chemistry. Philadelphia: W.B. Saunders
Company (1994), 959.