- Diseases, Disorders & Conditions
Measuring Blood Glucose Levels: What are mg/dL and mmol/L?
What are mg/dL and mmol/L?
There are two measurement systems for measuring blood glucose levels. Blood glucose levels are measured using either mg/dL or mmol/L. The traditional unit for measuring blood glucose is mg/dL (milligrams per deciliter) which is used in the U.S and a number of other countries. The Systeme International (SI) or world standard unit for measuring blood glucose is mmol/L(millimoles per liter) which is used in many areas of the world, specifically Europe.
Most glucose meters have a switch or option that allows you to select which system you want to use. Check the manual that came with your glucose meter or visit the glucose meter manufacturer’s website for instructions on how to switch the settings.
Convert Between mg/dL and mmol/L
To convert mg/dL to mmol/L, divide by 18.
130 mg/dL would be 7.2 mmol/L
To convert mmol/L to mg/dl, multiply by 18.
6.5 mmol/L would be 117 mg/dL
This conversion rule refers only to glucose.
Units of Measure
mmmol/L refers to the number of molecules in a substance; the count of glucose molecules(moles) per liter of blood.
mg/dL refers to the ratio of weight to volume; the weight of the glucose per deciliter.
The units of measurement are different but they do measure the same thing, blood glucose levels.
need to eat something quickly
4.5 to 7.0
80 to 125
5 to 7.2
70 to 130
normal before eating for diabetics
What Is Being Measured?
Most blood home glucose meters give a glucose result that is a plasma value.
Laboratories use the plasma portion of blood to measure blood glucose. Home glucose meters work with a sample of whole blood. Most home glucose meters are plasma calibrated. Whole blood is measured then the reading is converted to a plasma scale. It makes it easier to compare the home glucose meter results to the blood results from a laboratory test.
Blood glucose concentration is slightly higher in blood plasma than in whole blood which generally means about 11% higher plasma values than whole blood values. Neither number is wrong; the blood glucose concentration is just slightly different in plasma than whole blood.
When converting mg/dL to mmol/L don’t be concerned about the hundredths place.
140mg/dL is 7.777777…..mmol/L round of to 7.8.
150mg/dL is 8.33333…..mmol/L round off to 8.3.
4.2mmol/L is 75.6 mg/dL either 75 or 76 mg/dL is appropriate.
Round off to make values easier to comprehend.