What is Glomerular Filtration Rate?
Have you ever heard your doctor say, “Your GFR looks good” or “Your GFR is low” during a health check-up? Many people wonder, “What exactly is GFR?”
Glomerular Filtration Rate (GFR) simply measures how well your kidneys are filtering waste from your blood. Think of it like a water filter: just as a filter cleans dirty water, your kidneys clean your blood. GFR tells us how efficiently this process is happening.
Kidneys, Glomeruli, and Filtration Rate
You have two kidneys, one on each side of your back. Inside each kidney are about one million tiny filtering units called glomeruli.
Glomeruli filter waste and extra water from your blood. This process is called “filtration,” and how well it happens is measured by the GFR.
Units of GFR
- Unit: mL/min/1.73m²
- This means how many milliliters of blood are filtered per minute per 1.73 square meters of body surface area (the average adult size).
What is a Normal GFR?
| Age | Normal GFR Range (mL/min/1.73²) |
|---|---|
| 20s | 90–120 |
| 40s | 80–110 |
| 60s | 70–100 |
| 80s | 60–90 |
Note: Kidney function naturally declines with age, so a slightly lower GFR is normal for older adults.
What Happens When GFR is Low?
A low GFR means your kidneys are not filtering your blood well enough. Waste products can build up and cause serious health problems.
Problems Caused by Low GFR
- Waste accumulation in the blood
- Imbalance of fluids and electrolytes
- Worsening high blood pressure
- Increased risk of heart disease
- Anemia and bone health problems
Real-Life Cases of Low GFR
Case 1: Mr. Kim, 55 years old
- During a routine check-up, Mr. Kim’s GFR was found to be 55.
- He had no symptoms but had diabetes and slightly high blood pressure.
- With early diagnosis, he started medication and diet changes (low salt, controlled protein intake) and successfully slowed down kidney damage.
Lesson: Even without symptoms, checking your GFR can help detect kidney issues early and manage them effectively.
Case 2: Mr. Park, 68 years old
- Mr. Park visited the hospital with fatigue and swelling and found his GFR was only 30.
- He was diagnosed with late-stage chronic kidney disease (CKD stage 3).
- Intensive blood pressure control, diet management, and specialist care were necessary.
Lesson: While some GFR decline is natural with age, rapid drops should be addressed immediately.
How is GFR Measured?
1. Blood Test (Creatinine-Based Estimate)
- A blood sample measures creatinine, a waste product, and formulas like CKD-EPI or MDRD estimate GFR.
2. 24-Hour Urine Collection
- Collecting all urine over a full day gives a direct measurement of kidney filtering ability.
3. Radioisotope Tests
- In special cases, a small amount of radioactive material is used to measure GFR precisely.
How to Keep Your GFR Healthy
1. Stay Hydrated
- Drinking 1.5 to 2 liters of water daily prevents dehydration and protects your kidneys.
2. Manage Blood Pressure and Diabetes
- High blood pressure and diabetes are major threats to kidney health.
- Medication and healthy habits are critical.
3. Eat a Low-Sodium Diet
- Reducing salt intake eases the burden on your kidneys.
4. Avoid Unnecessary Medications
- Overuse of painkillers (like NSAIDs) and some herbal remedies can harm kidneys.
- Always consult your doctor.
5. Exercise Regularly
- Moderate aerobic exercise benefits overall health, including your kidneys.
Summary: GFR is the Key to Kidney Health!
Glomerular filtration rate shows how well your kidneys are working. Early detection and proper management can help you live a healthy life. Make regular health check-ups a habit, manage blood pressure and diabetes, and cherish your kidneys!
Predicting the prognosis of Chronic Kidney Disease with KFRE: