Glucose · high result
What does a high Glucose mean?
Short answer
A high fasting glucose (100–125 mg/dL is impaired fasting glucose; 126 mg/dL or higher on two occasions is diabetes) usually reflects insulin resistance or insufficient insulin. A non-fasting sample, stress, illness, steroids and a poor night's sleep raise it too, so the first step is to confirm it was truly fasting and repeat, or check A1c.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
When does this result need same-day care?
- Glucose above 250–300 mg/dL with vomiting, abdominal pain, drowsiness or rapid breathing — emergency care
What is the normal range for Glucose?
- age 18+, fasting: 70.0 – 99.0 mg/dL
Fasting values above 100 mg/dL can indicate prediabetes; above 125 mg/dL on two separate tests suggests diabetes.
Full reference table, citations and testing options: Glucose biomarker page.
What are the common causes of high Glucose?
- Not actually fasting (food, sugary drinks, coffee with milk within 8 hours)
- Prediabetes or diabetes
- Acute illness, pain or stress (adrenaline and cortisol raise glucose)
- Glucocorticoids and some other medications
- Pancreatic disease, Cushing's syndrome (rare)
What symptoms go with high Glucose?
- Often none
- Thirst, frequent urination, fatigue, blurred vision at higher levels
What do clinicians usually check next?
- Repeat fasting glucose or hemoglobin A1c to confirm
- Fasting insulin to gauge insulin resistance
- Lipid panel and kidney function as part of the metabolic picture
Follow-up tests available at TestWell: Lipid Panel ($24.99), Hemoglobin A1c ($21.99).
The ADA suggests re-screening at least every 3 years when fasting glucose is normal, and at least once a year with prediabetes (100–125 mg/dL). A single fasting result at or above 126 mg/dL is confirmed with a repeat test — or an A1c — before it counts as diabetes.
How do you recheck Glucose?
Prices are cash-pay; every order adds one $6 lab processing fee. Physician authorization is included; no insurance or referral needed.
| Test or panel | Type | Price | Fasting | Results |
|---|---|---|---|---|
| Basic Metabolic Panel | Test · 8 biomarkers | $20.99 | Yes | 1–3 business days |
Common questions
Is 105 mg/dL fasting glucose bad?
It falls in the impaired fasting glucose (prediabetes) range of 100–125 mg/dL. It's a signal to confirm with an A1c and act on diet, activity and weight — the range where change works best.
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.