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45
You may still have a variation from the result because
blood glucose levels can change significantly over short
periods, especially if you have recently eaten, exercised,
taken medication, or experienced stress*
2
. In addition, if
you have eaten recently, the blood glucose level from a
finger stick can be up to 70 mg/dL (3.9 mmol/L) higher than
blood drawn from a vein (venous sample) used for a lab
test*
3
. 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 (severe dehydration) may also cause a
meter result to be different from a laboratory result.
References
*2: Surwit, R.S., and Feinglos, M.N.: Diabetes Forecast (1988), April,
49-51.
*3: Sacks, D.B.: “Carbohydrates. “ Burtis, C.A., and Ashwood, E.R.( ed.),
Tietz Textbook of Clinical Chemistry. Philadelphia: W.B. Saunders Com
pany (1994), 959.
