Doctor's Assessment Included
Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
Fasting Glucose: What Does Your Blood Sugar Say?
Fasting glucose measures the sugar in your blood after not eating for at least 8 hours. This test provides insight into how your body processes blood sugar. An abnormal fasting glucose value may indicate changes in your sugar metabolism. As you age, the way your body processes sugar may change. Monitoring your fasting glucose value can therefore be useful. The information on this page is intended as general information and is not a substitute for professional medical advice. Always discuss your results with a doctor.
Reference Ranges
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.
What It Measures
eGFR is not a direct measurement but a calculation. Based on your creatinine, age, and sex, it estimates how many millilitres of blood your kidneys filter per minute. The CKD-EPI formula is the current standard in the Netherlands.
Chronic kidney disease staging based on eGFR is: > 90 ml/min is normal (stage 1), 60–89 is mildly reduced (stage 2), 45–59 is mildly to moderately reduced (stage 3a), 30–44 is moderately to severely reduced (stage 3b), 15–29 is severely reduced (stage 4), and < 15 ml/min is kidney failure (stage 5).
An eGFR between 60 and 90 without other signs of kidney damage (protein in urine, abnormal urine sediment) is often physiological in the elderly and does not necessarily indicate disease.
Why It Matters
Chronic kidney damage is largely irreversible, but progression can be slowed or stopped if detected early. eGFR is the cornerstone of that early detection. Diabetes and high blood pressure together account for more than 60% of all cases of chronic kidney damage — periodic eGFR monitoring in these patient groups is therefore essential.
At an eGFR below 60 ml/min, medication adjustments are often needed because many drugs are excreted by the kidneys. The dosage of contrast agents for CT scans must also be adjusted.
When to Test
eGFR is automatically calculated when creatinine is measured. It is useful with risk factors for kidney damage: diabetes, high blood pressure, family history of kidney problems, long-term NSAID use, and for everyone over 50 as part of a preventive check. Fasting is not required.
Symptoms
Low Levels
High Levels
Recommendations
Male
Low eGFR indicates reduced kidney function. Consult a nephrologist for evaluation and management.
Normal to high eGFR indicates healthy kidney function. Maintain kidney-healthy habits.
Female
Low eGFR indicates reduced kidney function. Consult a nephrologist for evaluation and management.
Normal to high eGFR indicates healthy kidney function. Maintain kidney-healthy habits.
Lifestyle Tips
Keep your blood pressure below 130/80 mmHg and blood sugar well regulated if you have diabetes — these are the two most effective measures to slow kidney function loss. Limit NSAID use, drink enough water, and avoid extremely high protein intake with already reduced kidney function. Stopping smoking also protects kidney function.