Am I Prediabetic or Diabetic?

If you think your blood sugar level may be higher than normal or just want to find out what it is you can test using a blood glucose meter. Blood glucose meters can be purchased at a pharmacy or some Drs will give you a meter for free. These meters record results as plama glucose.

You need to test your blood sugar levels after eating a meal which is high in carbohydrates (75 grams or more). Potatoes, rice, pasta or bread are all high in carbohydrates but you can calculate the exact amount of carbs at the Calorie King website.

Testing your blood glucose level with a meter.

  • Read the meter instructions carefully before testing so you are familiar with how the meter and test strips work.
  • Test you level first thing in the morning before you eat any food. This reading will be your “Fasting Blood Sugar”.
  • Eat a meal with about 75 grams of carbohydrates (1 large potato, 1 large bagel or 1-2 cups of cooked white rice).
  • Test your blood sugar level with the meter 1 hour after eating.
  • Test your blood sugar level again 2 hours after eating.

What these numbers mean.

Most meters are accurate to within a 10-20% margin of error. If your meter reads 100 mmol/L (5.5 mg/dl) the actual reading could be between 90-110 mmol/L (5-6.1 mg/dl). You should read your meter instructions before testing to find out its accuracy.

Normal blood sugar level

If your numbers never went past 100 mmol/L (5.5 mg/dl) at 1 hour post-meal or at any other times then your numbers are normal and there is nothing to worry about.

If your blood sugar level never went past 140 mmol/L (7.8 mg/dl) one hour after your 75 gram carb meal and was below 120 mmol/L ( two hours after your meal then these numbers are within the normal range for blood glucose. The following table from the Joslin Diabetes Center outlines the usual blood glucose ranges for a person who does and does not have diabetes.

Time of Check Goal plasma blood glucose ranges for people without diabetes (mmol/L)
Goal plasma blood glucose ranges for people with diabetes (mmol/L)
Before breakfast (fasting) < 100 70 – 130
Before lunch, supper and snack < 110 70 – 130
Two hours after meals < 140 < 180
Bedtime < 120 90- 150
A1C (also called glycosylated hemoglobin A1c, HbA1c or glycohemoglobin A1c) < 6% < 7%

< = less than > = greater than
> = greater than or equal to
< = less than or equal to

Impaired Glucose Tolerance (IGT)

If your blood glucose levels went past 140 mmol/L (7.8 mg/dl) at one hour and were higher than 120 mmol/L (6.6 mg/dl) at two hours then you might have Impaired Glucose Tolerance (IGT). Another name for IGT is Prediabetes.

Impaired Glucose Tolerance (IGT) is the name given to define blood glucose levels that are higher than normal, but below the level of a person with diabetes. IGT is a combination of:

  • Impaired secretion of insulin
  • Reduced insulin sensitivity (insulin resistance)

In people with IGT, the rise in blood glucose that occurs after consuming 75 g glucose is greater than normal, but not as high as in people with type 2 diabetes.