Glucose Level of Blood Vs. Plasma

Glucose is a simple carbohydrate that serves as the primary source of energy for living organisms. Glucose levels are measured by blood and urine tests, and like any other body chemistry, it has normal and abnormal ranges.

Background

• Before the invention of the blood glucose meter more than 20 years ago, blood glucose levels were ordered by your physician and tested in a hospital lab or other clinical laboratory. Normal--and abnormal--glucose ranges were established using plasma.

Considerations

• The invention of the blood glucose meter provided diabetics with the opportunity to monitor their own glucose levels at home any time of the day or night, without being first seen by their physician.

Specimen Collection

• Most clinical laboratories use plasma or serum from blood obtained by venipuncture for glucose testing. The blood glucose meter uses a drop of whole blood, usually obtained by finger puncture.

Comparison

• Fasting, whole-blood glucose levels in individuals with normal hematocrits is approximately 10 percent to 12 percent lower than fasting plasma glucose levels. In his chapter on "carbohydrates," Dr. David B. Sacks offers the following as sample reference intervals for fasting glucose levels: plasma/serum: 74 to 99 mg/dL; whole blood: 65 to 95 mg/dL.

Features

• The fasting plasma glucose is the most common marker for diabetes mellitus. Many of the glucose meters on the market use whole blood samples but report the glucose result in the plasma phase.