Good to knowOne result rarely tells the whole story. Your provider looks at your results together with your symptoms, exam, and other tests.
What the test is
Glucose is also part of the basic and comprehensive metabolic panels.
Why it's done
- Screening for diabetes or prediabetes
- Symptoms of high blood sugar, like thirst and peeing a lot
- Symptoms of low blood sugar, like shakiness, sweating, or confusion
Getting ready and what happens
- For a fasting test, have nothing but water for at least 8 hours.
How the test is done
- A health worker cleans the skin, puts a band around your arm, and draws blood from a vein with a small needle. It takes a few minutes.
What the results mean
| Result | Typical range for adults |
|---|---|
| Normal fasting | 70 to 99 mg/dL |
| Prediabetes (fasting) | 100 to 125 mg/dL |
| Diabetes (fasting) | 126 mg/dL or higher on two tests |
| Random test suggesting diabetes | 200 mg/dL or higher with symptoms |
| Low blood sugar | Below 70 mg/dL |
Normal ranges vary from lab to lab and can differ by age, sex, and pregnancy. Your report lists your lab's own range next to each result. A result a little outside the range is often not a problem.
High
May mean prediabetes or diabetes. Stress, illness, and steroid medicines can also raise it.
Low
Most often from diabetes medicines. Without diabetes, low sugar needs more testing.
When a result needs quick action
Call 911Blood sugar below 54 mg/dL with confusion or passing out, or over 300 mg/dL with vomiting, confusion, or fast breathing
Questions to ask your provider
- What do my results mean for me?
- Do I need to repeat this test or have other tests?
- Do I need an A1C or glucose tolerance test?
- What should my home readings be?
Risks
A blood draw is very safe. You may have slight pain or a small bruise where the needle went in.
Related conditions
Related medicines
Related tests
Sources
Last updated 2026-11-13.