Glucose Tolerance Test:This test assesses the body's ability to process glucose. It involves fasting overnight for at least 8 hours and no more than 16 hours. Initially, the fasting blood glucose level is checked. Afterward, the individual consumes 75 grams of glucose (100 grams for pregnant women), typically in a sweetened liquid form. Blood samples are collected up to four times to monitor glucose levels.To ensure accurate results, the person should be healthy, without any illnesses like a cold, and should maintain normal activity levels, avoiding prolonged rest such as hospitalization. Medications that could influence blood glucose should be avoided. Three days leading up to the test, the individual should consume a diet high in carbohydrates (150-200 grams daily). On the test day, smoking or drinking is not allowed.The test measures blood glucose levels five times over three hours. In individuals without diabetes, glucose levels rise and fall rapidly. In those with diabetes, glucose peaks higher than usual and does not decrease swiftly. Those with glucose levels between normal and diabetic are said to have "impaired glucose tolerance" (IGT). People with IGT aren't diabetic, and only 1-5% progress to diabetes annually. Upon retesting, up to half of those with IGT may have normal glucose levels. Weight loss and exercise can help normalize glucose levels in IGT individuals.Oral glucose tolerance relies on several factors, such as the intestine's glucose absorption ability, the liver's capacity to store glucose, the pancreas's insulin production, the effectiveness of the insulin produced, and the body's cellular sensitivity to insulin.Test outcomes may show:- Normal glucose tolerance- Abnormal glucose tolerance- Reduced glucose tolerance, where blood glucose spikes sharply before gradually returning to normal, as seen in conditions like: - Hemochromatosis - Excess growth hormone (acromegaly) - Insulin-producing tumors - Liver damage- Enhanced glucose tolerance, where glucose levels peak lower than normal, as in: - Addison's disease (adrenocortical insufficiency) - Insulinoma (an insulin-producing tumor) - Hypopituitarism (pituitary gland underactivity) - Hypothyroidism (thyroid underactivity)
