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24 Mar

Blood Glucose Tests

How to read your medical test report: Blood glucose tests

 All you need to know about reading your blood glucose test report.


Glucose is a type of sugar that is produced by the digestion of dietary carbohydrates. It is transported by the blood to all parts of the body and is body’s main source of energy. Insulin, a hormone produced by the pancreas, transfers extra glucose from the blood to muscle, fat, and liver cells where it is stored. Blood glucose levels changes indicate abnormal digestion process. People with diabetes often have high levels of glucose in their blood.

Prediabetes is a condition where the blood glucose is higher than normal but not high enough to be confirmed as diabetes. It could lead to diabetes if appropriate measures are not taken.

Blood glucose tests – what are they?

Blood glucose tests measure the amount of sugar (glucose) in your blood sample. The glucose may be measured randomly (any time of the day), in the morning before breakfast or after a meal (postprandial). In glucose tolerance test, your blood sugar levels are measured a short time after you drink an oral glucose solution. Depending on the purpose of the test, you may be required not to eat for 8-10 hours before the test. You can measure your blood sugar level at home with an electronic blood glucose meter.

When is the test recommended?

Blood glucose tests are used to screen the blood for undetected hyperglycemia (high blood sugar) or hypoglycemia (low blood sugar). They help diagnose diabetes and monitor glucose levels in diabetics. Routine screening for diabetes is recommended for adults above the age of 45 and people with high-risk factors like excessive weight, sedentary lifestyle, unhealthy diet, history of gestational diabetes, a family history diabetes, etc. In overweight children, starting at age 10, and in overweight adults (BMI > 25) screening every 2 years for diabetes is recommended.

Reading your blood glucose test report

Blood glucose levels do not remain constant throughout the day. The levels are lowest in the morning before food consumption. The levels rise for 1-2 hours after meals. The normal blood glucose level ranges between 80-110 mg/dl. The average blood glucose level is 90 mg/dl. Several tests that check blood sugar levels help diagnose diabetes. Each of these tests usually needs to be repeated before confirming the diagnosis. You are at a risk of developing diabetes if your test reports show prediabetes. Progression of prediabetes to diabetes can be slowed down or prevented with lifestyle modifications like low-fat, low-calorie diet and regular physical activity. If you are diagnosed with diabetes, you need to change your lifestyle to manage your diabetes. Yoga asanas can help reduce blood sugar level.

1. Routine blood sugar

Your blood sample is taken at any random time of the day with no preparation. With repeated tests, a random glucose level higher 200 mg/dL may indicate diabetes.

Normal range: 80 to 110 mg/dL

Shortly after eating: up to 140 mg/dL

High: > 200 mg/dL

2. Postprandial sugar

The test determines the amount of glucose in your blood after a meal. Blood glucose measured exactly 2 hours after eating a meal is called a 2-hour postprandial blood sugar. If you are healthy, your blood sugar usually goes back down in 2 hours.  It may still be elevated if you have diabetes. A blood sugar value between 140 and 200 mg/dL is termed ‘impaired glucose tolerance’. Greater than 200 mg% of blood sugar two hours after a meal on two separate occasions may indicate diabetes. The test also serves to monitor whether blood sugar levels are successfully being controlled in a diabetic person.

Normal: < 140 mg/dL

Impaired glucose tolerance: 140-200mg/dL

High: > 200mg/dL

3. Fasting blood sugar (pre-prandial)

The test determines your blood sugar level after an overnight fast. You should not eat anything for 8-10 hours before the test. Usually, this test is done first thing in the morning. Diabetes is diagnosed when two separate blood tests show you are fasting blood glucose level greater than 125 mg/dL.

Normal range: 70 to 100 mg/dL

Prediabetes: 100 to 125 mg/dL

Diabetes: > 125 mg/dL (on two separate testing)

4. Oral glucose tolerance test

This test also requires you to fast for at least 8 hours after which you have to drink a glass of water mixed with 75g of glucose. After 2 hours of taking the fluid, your blood is checked for sugar level.

Normal: <140 mg/dL

Prediabetes: 140 to 199 mg/dL

Diabetes: > 200 mg/dL (on two separate testing)

5. Glycated hemoglobin test (HbA1C)

HbA1C test measures the quantity of glucose attached to hemoglobin in red blood cells. It detects your average blood glucose levels over the period of three months. The test is used for diagnosing type 2 diabetes. It also tells how well your diabetes is managed over time and checks if the blood sugar reducing treatment is effective. If you have been diagnosed with diabetes, then you should get HbA1c levels tested twice a year. An A1C above 7% implies that you are susceptible to diabetic complications like diabetic ketoacidosis, diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, erectile dysfunction, etc.

Normal: < 5.7%

Prediabetic: 5.7 to 6.4%

Diabetes: > 6.4% (on two separate testing)