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Metabolic

Fasting Glucose: Normal Values and What a High Result Means

Fasting glucose is one of the most important screening markers for metabolic health. Regular testing supports early detection of pre-diabetes and diabetes prevention.

Doctor's Assessment Included

Reference Ranges

See the value that applies to you:

Choose male or female — this range differs by sex.

Enter your age — this range changes with age.

This range also depends on context such as cycle phase or sample material; the highlighted rows apply to your group.

Male Your group
mmol/l
Low 3.5 Normal 5.5 High
Female Your group
mmol/l
Low 3.5 Normal 5.5 High

Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.

Check your own value

What It Measures

This test measures blood glucose after fasting for at least 8 hours. It reflects your body's baseline ability to regulate blood sugar without the influence of recent food intake.

Why It Matters

Fasting glucose is a cornerstone of metabolic health assessment. Elevated levels may indicate pre-diabetes or diabetes, while very low levels can also be clinically significant. Consult your healthcare provider for interpretation.

When to Test

Testing is recommended as part of routine health screening, especially if you have risk factors such as family history of diabetes, overweight, physical inactivity, or a history of gestational diabetes.

Symptoms

Low Levels

Low fasting glucose (hypoglycaemia) may cause shakiness, sweating, confusion, dizziness, rapid heartbeat, and in severe cases, loss of consciousness. Seek immediate medical attention for severe symptoms.

High Levels

High fasting glucose may initially cause no symptoms but over time can lead to increased thirst, frequent urination, fatigue, blurred vision, and slow wound healing.

Recommendations

Male

If Low

Low fasting glucose may indicate hypoglycaemia. Consider evaluation.

If High

Elevated fasting glucose may indicate pre-diabetes or diabetes. Consider HbA1c testing.

Female

If Low

Low fasting glucose may indicate hypoglycaemia. Consider evaluation.

If High

Elevated fasting glucose may indicate pre-diabetes or diabetes. Consider HbA1c testing.

Lifestyle Tips

Maintain a balanced diet with controlled portions, regular physical activity, a healthy weight, and adequate sleep. Limit refined sugars and processed carbohydrates. These lifestyle factors play a key role in blood sugar management.

Frequently Asked Questions

How long should I fast before this test?
You should fast for at least 8 hours before the test. Water is usually permitted. Follow your healthcare provider's specific instructions.
What fasting glucose level indicates diabetes?
Diagnostic thresholds vary by guideline. Your healthcare provider can interpret your results in context and advise on next steps if levels are elevated.
Can stress affect fasting glucose?
Yes, stress can temporarily raise blood sugar levels through cortisol release. If you were under significant stress during testing, discuss this with your healthcare provider.

Test Products

This marker is included in the following test panels.

Whoop

A 44-biomarker comprehensive health panel inspired by WHOOP Advanced Labs — a deep look at metabolism, cardiovascular risk, hormones, liver, kidney and inflammation.

SHBG (Sex Hormone Binding Globulin) TSH (Thyroid Stimulating Hormone) ALT (Alanine Aminotransferase) LDL Cholesterol Cortisol DHEA-S Estradiol (E2) Free Testosterone FSH (Follicle Stimulating Hormone) LH (Luteinizing Hormone) Total Testosterone Bicarbonate Calcium Chloride Ferritin Iron (Serum) Magnesium Potassium Sodium Transferrin CRP (C-Reactive Protein) Homocysteine Glucose (Fasting) HbA1c (Glycated Hemoglobin) ApoB (Apolipoprotein B) HDL Cholesterol Omega-3 Index Total Cholesterol Albumin HOMA-IR ALP (Alkaline Phosphatase) AST (Aspartate Aminotransferase) Bilirubin (Total) Total Protein Urea (BUN) Creatinine Vitamin D (25-OH) eGFR (Estimated Glomerular Filtration Rate) Insulin (Fasting) Leukocyte Differential Transferrin Saturation Lipoprotein(a) Triglycerides Basic Blood Count
€499,-

InsideTracker

A 36-biomarker performance and longevity panel inspired by InsideTracker Ultimate — covering heart, hormones, metabolism, inflammation, recovery and iron status.

SHBG (Sex Hormone Binding Globulin) TSH (Thyroid Stimulating Hormone) ALT (Alanine Aminotransferase) LDL Cholesterol GGT (Gamma-Glutamyl Transferase) Cortisol DHEA-S Estradiol (E2) Free Testosterone Total Testosterone Folate (Folic Acid) Vitamin B12 Calcium Ferritin Iron (Serum) Magnesium Magnesium (Intracellular) Potassium Progesterone Sodium Transferrin CRP (C-Reactive Protein) Glucose (Fasting) HbA1c (Glycated Hemoglobin) ApoB (Apolipoprotein B) HDL Cholesterol Total Cholesterol Albumin AST (Aspartate Aminotransferase) Vitamin D (25-OH) Insulin (Fasting) Leukocyte Differential Creatine Kinase (CK) Transferrin Saturation Triglycerides Basic Blood Count
€399,-

Glucose (Fasting)

€7,-