Final answer:
Prior to an oral glucose tolerance test, a patient must follow a carbohydrate-rich diet for three days and fast for 12-14 hours. After fasting, the patient drinks a glucose solution, and their blood glucose levels are monitored to assess glucose tolerance and potential diabetes mellitus.
Step-by-step explanation:
Preparation for an Oral Glucose Tolerance Test (OGTT)
Before undergoing an oral glucose tolerance test (OGTT), a patient must adhere to a specific dietary and fasting protocol to ensure accurate results. This includes consuming a carbohydrate-rich diet, with more than 150 grams of carbohydrates per day, for three days prior to the test. This is crucial as it ensures that the patient's carbohydrate metabolism is at a normal level.
On the day of the test, the patient must fast for 12-14 hours. Following the fasting period, the patient is given an oral dose of glucose to drink. The standard dose is 75 grams of glucose dissolved in 300 ml of water for adults in developed countries, or a dose adjusted to body weight (0.75 grams per kilogram body weight for Indian adult males).
After ingesting the glucose solution, the patient's blood glucose levels are measured at regular intervals, usually every half hour. This enables healthcare providers to assess how well the patient's body handles the influx of glucose and to identify potential diabetes mellitus. If the patient's blood glucose levels rise significantly and fail to return to normal within 2-2.5 hours after ingestion, it may indicate a glucose intolerance or diabetes mellitus.