Plasma Glucose Meters and Whole Blood Meters
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, or ask a diabetes educator to find out how your meter reads.
As of July, 2002, the Joslin Web site is listing target blood glucose levels on its Online Diabetes Library as plasma glucose levels to reflect this change. For individuals who use the Online Diabetes Library as a resource to refer to on a regular basis, this is the reason for slight changes in certain target levels presented in this material.
Attention visitors from outside the US: You can easily convert US to non-US blood glucose levels by clicking here.
Page last updated: May 24, 2019