Mild kidney disease means your kidneys have early signs of damage but are still filtering blood at or near normal capacity. It covers Stage 1 and Stage 2 of chronic kidney disease (CKD), where your estimated glomerular filtration rate (eGFR), a measure of how well your kidneys filter waste, is still above 60 mL/min. Most people with mild kidney disease feel completely normal, and many don’t know they have it until routine blood or urine tests pick it up.
How Mild Kidney Disease Is Defined
CKD is diagnosed when abnormalities in kidney structure or function persist for more than three months. What makes the early stages tricky is that your kidneys can show damage while still doing their job reasonably well. Stage 1 means your eGFR is 90 or above, which is considered normal filtering capacity, but other tests have detected signs of kidney damage. Stage 2 means your eGFR has dipped slightly to between 60 and 89, again with evidence of damage present.
The key detail: a mildly reduced eGFR in the 60 to 89 range, on its own, does not count as CKD. There must also be a marker of actual kidney damage. The most common marker is albumin in your urine. Albumin is a protein your kidneys should keep in your blood. When it leaks into urine at levels above 30 mg/g on a urine albumin-to-creatinine ratio (uACR) test, it signals that the kidney’s filtering units are injured. Levels between 30 and 300 mg/g indicate moderate albumin leakage, while levels above 300 mg/g suggest more significant damage. Other markers include blood in the urine, structural abnormalities seen on imaging, or a history of kidney transplant.
Why It Usually Causes No Symptoms
At stages 1 and 2, your kidneys still have enough reserve capacity to handle their daily workload. You won’t typically feel tired, swollen, or different in any noticeable way. Symptoms like fatigue, swelling in the hands or ankles, and changes in urination frequency tend to appear later, when kidney function drops more significantly. This is why mild kidney disease is almost always caught through lab work rather than symptoms, often during screening for diabetes or high blood pressure.
Common Causes and Risk Factors
The two biggest drivers of early kidney damage are diabetes and high blood pressure. Over time, elevated blood sugar injures the tiny blood vessels inside the kidneys, while uncontrolled blood pressure puts excess force on those same structures. Together, these two conditions account for the majority of CKD cases.
Other causes include glomerulonephritis (inflammation of the kidney’s filtering units), polycystic kidney disease, recurrent kidney infections, and prolonged use of certain pain medications. Family history of kidney disease, obesity, smoking, and being over 60 all raise your risk. CKD affects roughly 15% of U.S. adults, and many of those cases are in the mild stages.
How It’s Diagnosed
Two simple tests form the foundation. A blood test measures your eGFR, which estimates how many milliliters of blood your kidneys filter per minute. A urine test measures your uACR, which detects abnormal protein leakage. Both tests need to show abnormal results persisting for at least three months before a CKD diagnosis is made, because temporary changes from dehydration, illness, or medication can briefly affect kidney markers.
If your eGFR comes back at 75 but your uACR is normal and there are no other signs of damage, you do not have CKD. Your doctor may simply recheck periodically. If your eGFR is 95 but your uACR is 45 mg/g on two tests three months apart, that qualifies as Stage 1 CKD despite your normal filtration rate.
How Likely It Is to Get Worse
Mild kidney disease does not automatically progress to kidney failure. A long-term study tracking adults over 20 years found that about 29% of participants moved into a worse CKD risk category over that entire period, mostly driven by increasing albumin in the urine rather than a dramatic drop in filtration rate. Among people starting in the lowest risk category, only about 7% shifted to the next worse category within any given five-year window, and just 0.1% progressed to a very high risk category.
The factors that push mild CKD toward more advanced disease are largely the same ones that caused it: uncontrolled blood sugar, high blood pressure, continued smoking, and rising albumin levels. People with diabetes face a steeper risk. On the other hand, those who manage their underlying conditions well can keep their kidney function stable for years or even decades.
What You Can Do to Protect Your Kidneys
Blood pressure control is the single most impactful lever. Current guidelines from the international kidney disease organization KDIGO recommend keeping systolic blood pressure (the top number) below 120 mmHg for most people with CKD. That target is lower than what many people expect, and it’s based on strong trial evidence showing it slows kidney decline and reduces heart disease risk.
Dietary changes in the early stages are generally modest. You won’t need the strict restrictions that come with advanced kidney disease. The main priorities are keeping sodium intake well below 2,300 mg per day (and possibly lower, depending on your situation), eating moderate amounts of protein so waste products don’t accumulate, and watching potassium intake if blood tests show your levels running high. A dietitian who specializes in kidney health can tailor these recommendations to your specific lab results.
Beyond diet, the standard guidance applies with extra urgency: maintain a healthy weight, stay physically active, quit smoking if you smoke, and keep blood sugar in a healthy range if you have diabetes. These steps protect not just your kidneys but your heart, since even mild CKD increases cardiovascular risk. In fact, that study of young adults found that an eGFR dropping below 60 strongly predicted future heart disease and death, even in people decades away from kidney failure.
What Monitoring Looks Like
Once mild CKD is confirmed, guidelines recommend checking your eGFR and uACR at least once a year. If your risk profile is higher, perhaps because of diabetes or albumin levels trending upward, your doctor may run those tests two or three times a year. At stages 1 and 2, you generally don’t need routine screening for complications like anemia or bone mineral disorders. Those become relevant at stage 3 and beyond.
The purpose of regular monitoring is straightforward: catching any downward trend early enough to intervene. A stable eGFR and steady or declining albumin levels over several years is reassuring. A pattern of worsening numbers signals the need for more aggressive management of blood pressure, blood sugar, or other contributing factors.