Glucose Blood Test
Below is a plain-language overview of the glucose blood test. The glucose blood test measures the amount of sugar (glucose) in your blood. It is commonly ordered to screen for diabetes or prediabetes, and to monitor blood sugar control in people already diagnosed with diabetes.
- Sample type
- blood
- Category
- Metabolic & Glucose
- Turnaround
- 1-3 business days
- Price
- $28
- Referral
- Not required
The glucose blood test measures the amount of sugar (glucose) in your blood. It is commonly ordered to screen for diabetes or prediabetes, and to monitor blood sugar control in people already diagnosed with diabetes.
What it measures
- Glucose (fasting) — Your blood sugar level after not eating for at least 8 hours.
- Glucose (random) — Your blood sugar level at any time, without fasting.
- Glucose (post-meal) — Your blood sugar level measured 1–2 hours after a meal or drink.
- Hemoglobin A1c — An estimate of your average blood sugar over the past 2–3 months.
Who it is for
A doctor or other healthcare provider typically orders this test during a routine checkup, if you have symptoms of high or low blood sugar, or if you have risk factors for diabetes.
Preparation
For a fasting glucose test, you will be asked not to eat or drink anything except water for 8–12 hours before the test. For a random or post-meal test, no special preparation is needed.
Results and what they mean
Results are usually reported as a number in milligrams per deciliter (mg/dL). A clinician interprets your result based on your medical history, symptoms, and other tests. This information is not medical advice; talk with your healthcare provider about what your results mean.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Availability by state
Direct-access online ordering for the glucose blood test is available in most states. It is currently unavailable in 6 states:
Everywhere else you can order confidentially and collect your sample at a certified site. Browse by state →
Frequently asked questions
Do I need to fast for a glucose blood test?
It depends on which type of glucose test you are having. A fasting glucose test requires 8–12 hours without food or drink except water. A random or post-meal test does not require fasting. Follow the instructions from your provider.
How long does it take to get results?
Results are typically available within 1–3 business days, though this can vary by lab and how the test was ordered.
Can I drink water before a fasting glucose test?
Yes, plain water is usually allowed. Avoid coffee, tea, juice, soda, and any other beverages that contain calories or caffeine unless your provider says otherwise.
What if my glucose result is high or low?
A single result outside the usual range does not always mean there is a problem. Your provider will consider your symptoms, other tests, and your overall health. Do not change any medication or diet based on a lab result alone—talk with your clinician first.