Calculating your MPG, or mean plasma glucose, is a useful method for glycemic monitoring (see references 1, 2 and 5). Mean plasma glucose, in simpler terms, is your blood sugar level averaged over a given period of time (see references 6 and 2). In a study on short-term hyperglycemia or raised blood-sugar levels in hospital patients, Dr. Prem Thomas concludes that the single-day MPG is the most useful calculation interval (see references 2). However, in an ADA journal paper, Dr. Richard J. Schrot states that most practitioners agree that A1C, a hemoglobin-glucose test that profiles three to four months and correlates with MPG, is the gold standard for glycemic control (see references 1).
Take regular blood sugar readings over the desired interval of time. For example, to calculate a single-day MPG, take blood sugar readings after each meal and before bed (see references 1 and 5). Log these readings for later reference. These readings are usually valued in mg/dl or milligrams per deciliter.
Add up all the logged blood sugar readings for the period to be calculated.
For example, if your four readings came out as 200 mg/dl, 300 mg/dl, 220 mg/dl and 240 mg/dl, add 200 + 300 + 220 + 240 = 960.
Divide the sum of the readings by the number of readings logged. This answer is your MPG level for the calculated period.
Continuing with the above example, 960 ÷ 4 = 240. Your MPG for this day is 240.
A1C Correlation Method
Have an A1C test performed by a licensed health practitioner. The A1C test usually uses a seven-point reading method, testing before and after each of three meals as well as before bed. (see reference 1)
Identify the result of your A1C test. Your A1C level is valued as a percentage. Your health practitioner/tester should provide this for you (see references 1 and 3).
Multiply your A1C level by 35.6. (see reference 4)
For example, if your A1C level was found to be 10.4 percent, multiply 10.4 X 35.6 = 370.24.
Subtract 77.3 from the product of your multiplication. The answer, rounded off, is your MPG for the period indicated by the A1C test. (see reference 4)
Continuing the above example, 370.24 – 77.3 = 292.94. In this case, once rounded off, 293 is your MPG level.
The American Diabetes Association’s Clinical Diabetes website offers a quick-reference chart of the correlations between A1C levels and MPG levels. (see resources 1)
- Clinical Diabetes: Targeting Plasma Glucose: Preprandial Versus Postprandial:
- Yale University: Glucometrics: Measuring Inpatient Glycemic Control
- Centers for Disease Control and Prevention: Diabetes Public Health Resource: Take Charge of Your Diabetes
- Pace Medical Applications: Hemoglobin A1C Calculator
- Net Doctor: Blood glucose levels
- Math Is Fun: How to Find the Mean
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