Hi found this at
www.joslin.org
Until the last couple of years, all blood glucose (blood sugar) meters read the glucose level in your blood sample as whole blood. Then several years ago one manufacturer developed a meter calibrated to read the blood glucose sample as if it were plasma. Why? Because the results of blood samples taken from your vein at your doctor's office or lab are reported as plasma. By having the meter record results as plama glucose, you and your healthcare team can more easily compare your lab tests with your blood glucose meter results. Several other meter manufacturers subsequently followed suit, so that today most newer meters provide blood glucose (sugar) readings as plasma glucose readings.
What's the difference?" you might ask. The difference is that plasma numbers read about 10 - 12% higher than the older whole blood numbers. So if your fasting and pre-meal blood glucose target is 90 - 130 mg/dl plasma glucose, it would be 80 - 120 mg/dl if your meter reads whole blood.
So, it's important for you to know what your meter reads, and then what your targets are for the meter you are using. Check your instruction book, contact the manufacturer of your meter
And this from Wikipedia
Glucose is measured in whole blood,
plasma or
serum. Historically, blood glucose values were given in terms of whole blood, but most laboratories now measure and report plasma or serum glucose levels. Because
red blood cells(erythrocytes) have a higher concentration of protein (e.g., hemoglobin) than serum, serum has a higher water content and consequently more dissolved glucose than does whole blood. To convert from whole-blood glucose, multiplication by 1.15 has been shown to generally give the serum/plasma level.