Endocrine glands in the pancreas release the hormones insulin and glucagon. These hormones control the blood glucose (sugar) levels in our body. Insulin promotes the transport of blood sugar to body cells. The cells absorb the glucose from the blood and convert it into energy. Insufficient insulin production, or problem in absorption of glucose by cells can lead to diabetes. Abnormal fluctuations in blood sugar levels can lead to serious health complications.
Main Types of Diabetes
Diabetes due to severe deficiency of insulin is called type 1 diabetes, and it is more prevalent in adults. It is an autoimmune disorder. When body cells become immune to insulin, the condition is referred to as type 2 diabetes. As the cells develop insulin resistance, blood sugar levels increase. Pancreas produces more and more insulin to control the elevated levels. But due to insulin resistance, it becomes difficult to control those levels. Capacity of the pancreas to produce insulin is limited and the high levels of insulin produced by the pancreas also seem to be insufficient to lower the blood sugar. High blood sugar levels are termed as hyperglycemia and low blood sugar levels are known as hypoglycemia.
Tests to Measure Blood Sugar Levels
A simple blood test helps measure the level of sugar in blood. The amount of sugar in blood, before and after eating, is significantly different. So, normally, it is first checked after fasting for about 8 hours (usually overnight fasting) and then again two hours after taking a meal. The first reading is known as fasting blood sugar while the latter is known as postprandial blood sugar count. Sugar from blood, measured any time during the day, is referred to as random blood sugar level. Sometimes the doctor asks you to drink a mixture of water and glucose (with certain fixed proportion), and then measures the amount of sugar in blood, after regular intervals like 30 minutes, one hour, two hours, etc. This test is known as oral glucose tolerance test (OGTT). A woman who does not have diabetes, may develop it during pregnancy. This is called gestational diabetes. Slightly higher than normal blood glucose levels indicate that the person has prediabetes, and the person is said to have impaired glucose tolerance (IGT).
Normal Blood Sugar Levels
Type of Test Normal Range IGT Range Diabetic Range
Fasting 70 – 100 mg/dL 100 – 125 mg/dL Above 126 mg/dL
Postprandial Up to 140 mg/dL 140 – 200 mg/dL Above 200 mg/dL
Random Up to 140 mg/dL 140 – 200 mg/dL Above 200 mg/dL
Glucose Tolerance Test Less than 140 mg/dL (7.8 mmol/L) From 140 to 200 mg/dL (7.8 to 11.1 mmol/L) Over 200 mg/dL (11.1 mmol/L) on more than one testing occasion
Note: mg/dL = milligrams per deciliter and mmol/L = millimoles/liter.
In the above chart, the values for OGTT are the values for blood sample drawn 2 hours after having a 75 gram glucose drink.
Normal Blood Sugar Count During Pregnancy
The following chart shows normal values of glucose for OGTT (Oral Glucose Tolerance Test) samples taken after ingesting 100 gram glucose drink:
Sample Collection Normal Glucose Count
Fasting glucose level (before drinking glucose drink) 95 mg/dL (5.3 mmol/L)
One hour after having glucose drink 180 mg/dL (10.0 mmol/L)
Two hours after having glucose drink 155 mg/dL (8.6 mmol/L)
Three hours after having glucose drink 140 mg/dL (7.8 mmol/L)
Normal Blood Sugar Count in Adults and Children
The following chart will help you compare normal blood glucose levels of an adult and a child.
Blood Sugar Level Children Adults
Normal 70 – 100 mg/dL 70 – 140 mg/dL
Low Below 70 mg/dL Below 70 mg/dL
High Over 140 mg/dL Over 180 mg/dL
Diabetes detected at an early stage can be easily controlled with proper diet and regular exercises. Increased hunger and thirst, increased frequency of urination (especially at night), undesired weight loss, excessive tiredness, blurred vision, slow healing of wounds, tingling sensation in hands or legs, new incidences of bed-wetting in children are some of the commonly noticed symptoms of prediabetes. Those who have a family history should regularly undergo blood tests, and should follow the instructions of doctors religiously.