My GFR Dropped? Should I Be Worried?

Not every change in your GFR is a sign of trouble! It's completely normal for your GFR to fluctuate due to hydration, diet, and lab variability. If you notice a drop, try not to panic—focus on the long-term pattern and talk to your doctor about any change greater than 20%.

If you’ve had blood tests to check your kidney function, you may have noticed that your GFR (glomerular filtration rate) sometimes goes up or down. This can feel alarming, but not every change is a cause for worry.

👉 Want a refresher on what GFR and CKD mean? [Read here »]

Why GFR Can Fluctuate

Should you worry about a slightly lower GFR? Holding your latest lab results can be stressful, especially when they show a drop from a previous test. In the image, the GFR went from 60 ml/min in January to 57 ml/min in April. According to our guidelines, this small change is likely normal variation! Learn why your GFR can fluctuate and the key percentage change that should prompt a call to your doctor.

It’s normal for GFR to change slightly between tests. Your hydration level, what you ate, and even lab variability can affect the number. That’s why small shifts don’t always mean your kidneys are getting worse.

What Counts as a Normal Change?

• Small changes (within 15–20%) → Usually normal and not cause for concern.Example: If your eGFR is 50 ml/min, a follow-up result anywhere between about 40 and 60 may just be normal variation.

• Bigger changes (more than 20%) → Could signal kidney injury or disease, especially if the change is persistent.

• Starting new medications (like blood pressure medicines or SGLT2 inhibitors) → A small drop is expected, but a drop greater than 30% should be reviewed by your doctor.

Protein in Urine: Another Important Clue

GFR isn’t the whole story. Protein in the urine (albuminuria) can appear before GFR goes down and is a key sign of early kidney damage. That’s why doctors check both blood and urine tests together.

What Should You Do?

• Don’t panic about a single test result.

• Focus on the pattern over time.

• Keep follow-up appointments and repeat labs if there’s an unexpected change.

• Talk to your doctor if you see a drop greater than 20%

✅ Bottom line: A GFR drop doesn’t always mean your kidneys are failing. Small ups and downs are normal. What matters most is whether the change is big, persistent, and paired with other signs of kidney injury.