eGFR stands for "estimated glomerular filtration rate." It's a calculation that estimates how much blood your kidneys are filtering every minute. The higher the number, the better your kidneys are working.
A healthy adult typically has an eGFR above 90 mL/min/1.73m². Below 60 for three months or longer is the threshold for chronic kidney disease (CKD). Below 15 usually means kidney failure and the need for dialysis or a transplant.
Your kidneys are full of tiny filters called glomeruli (singular: glomerulus). Each kidney has about a million of them. Their job is to clean your blood — pulling waste, excess salt, and excess water out, and sending them to your bladder as urine.
eGFR estimates how much blood (in mL) your glomeruli filter every minute, scaled to a standard body size. So an eGFR of 60 means your kidneys are filtering about 60 milliliters of blood per minute.
You can't measure GFR directly without a complicated lab procedure. Instead, doctors estimate it using a formula that includes:
- Your creatinine (a waste product your muscles make)
- Your age
- Your sex
- (Sometimes) your race — though most modern formulas have moved away from this
That estimate is what shows up on your blood test as "eGFR."
| eGFR Range | CKD Stage | What it means |
|---|
| 90+ | Stage 1 (if other signs of damage) | Normal kidney function |
| 60-89 | Stage 2 | Mildly reduced — usually no symptoms |
| 45-59 | Stage 3a | Moderately reduced |
| 30-44 | Stage 3b | Moderate to severely reduced |
| 15-29 | Stage 4 | Severely reduced — preparing for dialysis |
| Below 15 | Stage 5 | Kidney failure |
A few important notes about reading these ranges:
- Stage 1 and 2 require other signs of kidney damage (like protein in the urine) to be considered CKD. An eGFR of 95 with a clean urine test usually just means healthy kidneys.
- Stage 3 onwards is diagnosed by eGFR alone if it stays low for three months or more.
- One low result doesn't mean CKD. eGFR fluctuates. A diagnosis requires a pattern, not a single number.
Your eGFR isn't a fixed number, it can swing 5-15 points up or down depending on factors that have nothing to do with kidney damage:
- Hydration. Being dehydrated lowers eGFR temporarily.
- Recent heavy exercise. Releases creatinine into the blood, which can drop the estimate.
- High-protein meals before testing. Especially if you ate red meat the night before.
- Some medications (NSAIDs like ibuprofen, certain antibiotics).
- Time of day. Morning samples often differ from afternoon ones.
- Lab variation. Different labs use slightly different methods.
This is why doctors look at trends over multiple tests, not single results. A drop from 55 to 50 in one quarter is mildly concerning. A drop from 55 to 50 to 45 to 40 over a year is serious.
Your eGFR will naturally decline a little with age — about 1 mL/min per year after 40 in healthy people. The goal of CKD management is to slow that decline.
| Trajectory | What it suggests |
|---|
| Stable for years | Excellent control |
| Dropping 1-2/year | Normal aging or well-controlled CKD |
| Dropping 3-5/year | Faster than ideal — talk to your nephrologist |
| Dropping 5+/year | Rapid progression — needs intervention |
Backed by major nephrology research, the biggest levers are:
- Blood pressure control. Aim for under 130/80 if your doctor agrees.
- Diabetes control (if you have it). HbA1c target is usually 7% or lower.
- Eating less protein than the average diet (especially less red meat).
- Limiting sodium to 2000mg/day.
- Avoiding NSAIDs like ibuprofen and diclofenac.
- Staying well-hydrated within your fluid limit.
- Stopping smoking.
Some medications (like ACE inhibitors, ARBs, and the newer SGLT2 inhibitors) can also slow decline significantly. Your nephrologist will know if these are right for you.
When you get your lab results, ask:
- What's my eGFR trend over the last 12 months?
- Is the change within normal variation, or are we seeing real progression?
- Are there medications I should be taking, or stopping, to protect my kidneys?
- What's my UACR (urine albumin-to-creatinine ratio)? This is the other key kidney number, and it sometimes tells doctors more than eGFR alone.
The bigger picture: eGFR is one number, not the whole story. Your potassium, phosphorus, blood pressure, and protein-in-urine all matter too. Tracking trends over time gives a much clearer picture than any single test.
DuoBean's Lab Translator pulls eGFR and other key values from your blood test PDFs and explains them in plain English. So you can understand your numbers even before your next appointment.