Glucose, found in carbohydrates is the body’s main source of energy. Insulin, released when glucose levels in the blood increase,  is the hormone that regulates glucose levels and helps cells use the glucose. When blood glucose levels remain high for a long period of time, it may cause damage to the eyes, kidneys, nerves and blood vessels.  High glucose levels that don’t return to normal after eating, may be a sign of diabetes. Therefore glucose testing is essential for diagnosing diabetes, and keeping track of the effectiveness of the treatment of diabetes.

Glucose testing

Testing for diabetes is highly recommended for people above 45 years old and anyone with high risk. These risks include: obesity, hereditary history of diabetes, a woman that delivered a baby weighing more than 4.1 kg or with a history of gestational diabetes,women with polycystic ovarian syndrome. Testing is also recommended for people with high blood pressure, low HDL cholesterol levels or high triglycerides levels and a history of cardiovascular disease.

  • Fasting blood sugar (FBS) is a blood test after fasting for at least 8 hours. It is the first test to perform when checking for prediabetes and diabetes.
  • If someone has diabetes then a Two-hour Oral Glucose Tolerance test is performed 2 hours after starting to eat a meal. This test will determine if the patient is taking the right amount of insulin with meals.
  • A casual blood glucose test is performed randomly throughout the day, regardless of food consumption, to show whether blood glucose levels vary widely which may be an indication of a problem.
  • The oral glucose tolerance test is used to diagnose prediabetes and diabetes. The test is a series of measurements taken after you drink a sweet liquid containing glucose. This type of testing is performed during pregnancy or after if high glucose levels were detected. The gestational diabetes one-step approach means that blood samples are collected after fasting, then 1-hour and 2- hours after you consume a 75-gram glucose drink. The gestational diabetes two-step approach means that a sample is taken 1 hour after a 50-gram glucose drink and a glucose challenge screening is performed (used during pregnancy).
  • Hemoglobin A1c testing is used to diagnose diabetes and how effective your medicine has been in controlling the diabetes the past 2-3 months. It does so by measuring how much glucose is stuck to red blood cells.

Test result parameters

Fasting blood sugar test

From 70-99 mg/dL (3.9 to 5.5 mmol/L) > Normal

From 100-125 mg/dL (5.6 to 6.9 mmol/L) > Prediabetes

Greater than or 126 mg/dL (7.0 mmol/L) on more than one testing > Diabetes

2-hour Oral Glucose Tolerance test

Less than 140 mg/dL (7.8 mmol/L) > Normal

From 140 to 199 mg/dL (7.8 to 11.1 mmol/L) > Prediabetes

Greater than or 200 mg/dL (11.1 mmol/L) on more than one testing occasion > Diabetes

Casual Blood Glucose Test

*Depends on when you last ate

Less than 125 mg/dL (6.9 mmol/L) > Normal

Greater than or 200 mg/dL (11.1 mmol/L) > Diabetes * We will order a fasting blood sugar test or A1c test to cross-reference the results.

Gestational Diabetes One-step Approach

Fasting: Greater than or 92 mg/dL (5.1 mmol/L)

1 hour: Greater than or 180 mg/dL (10.0 mmol/L)

2 hours: Greater than or 153 mg/dL (8.5 mmol/L)

Gestational Diabetes Two-step Approach

Less than 140 mg/dL (7.8 mmol/L) > Normal

Greater than 140 mg/dL (7.8 mmol/L) > Abnormal, further testing is advised.

Hemoglobin A1c

From 4%-5.6% > Normal

From 5.7%- 6.4% > Risk of diabetes

Greater than or 6.5% > Diabetes

People with diabetes ideal A1c measurement is below 7%.