A 3-hour glucose test evaluates how your body processes sugar and is frequently used to identify conditions such as gestational diabetes. Receiving accurate results and ensuring a smooth experience during this lengthy test relies heavily on proper preparation. This article outlines the necessary steps to prepare for your 3-hour glucose test, from dietary adjustments to what you should expect on the day of the test.
Dietary Preparations Leading Up to the Test
For three days before your 3-hour glucose test, maintain your usual diet without intentionally restricting or increasing carbohydrate intake. This reflects your typical glucose metabolism. Some healthcare providers advise consuming at least 150 grams of carbohydrates daily to ensure accurate results.
Include carbohydrate-rich foods like breads, cereals, pasta, rice, potatoes, corn, bananas, and yogurt. You might also be encouraged to add extra carbohydrate servings, such as two slices of bread, a piece of cake, a candy bar, or a can of non-diet soda daily. Avoiding dieting before the test is important, as this could lead to inaccurate results.
Fasting and Medication Guidelines
A fasting period of 8 to 14 hours, usually overnight, is required before your initial blood draw. During this time, only plain water is permitted. Avoid all other beverages, including coffee, tea, diet sodas, and sugar-free drinks. Smoking, chewing gum, and eating cough drops or hard candy are also prohibited.
Discuss all current prescriptions, over-the-counter drugs, and supplements with your healthcare provider in advance. Your doctor will advise whether to continue or temporarily stop certain medications, as some can affect blood glucose levels. Some sources suggest avoiding over-the-counter medications for 12 hours before the test, and iron or vitamin pills might be discouraged the night before.
What to Bring and What to Expect on Test Day
On test day, bring your identification and insurance card. Since the test involves a significant waiting period, bringing a book, magazine, or other entertainment like a laptop with Wi-Fi can help pass the time. Also, bring a snack and water for after the test, as you will likely be hungry once it concludes.
The test begins with a fasting blood draw to measure your baseline glucose level. After this, you will drink a glucose solution, usually 100 grams, within five minutes. This solution is often described as very sweet, similar to a flat soda, and some individuals may experience nausea, lightheadedness, or sweating after consuming it. If you feel unwell, inform the lab staff.
Following the glucose drink, blood samples are drawn at 1 hour, 2 hours, and 3 hours. Remain at the testing facility for the entire test, as activity can interfere with results. Do not eat or drink anything other than plain water between draws. After the final blood sample, you may resume normal diet and activities.