Kidney Health 101: What Your eGFR and Urine Tests Are Telling You

Your kidneys filter your entire blood supply many times a day, removing waste, balancing fluids and minerals, and helping control blood pressure. They’re remarkably good at their job — so good that they can lose a large share of their function before you notice anything is wrong. That’s why chronic kidney disease (CKD) is often called a silent condition, and why two routine tests matter so much.

The Two Tests That Matter Most

1. eGFR (estimated glomerular filtration rate). This comes from a standard blood test that measures creatinine, a waste product your kidneys clear. Using your creatinine level and age, the lab estimates how well your kidneys are filtering. Generally, an eGFR of 60 or higher is considered in the normal range, while a value below 60 for three months or more suggests chronic kidney disease. Lower numbers mean less filtering ability.

2. Urine albumin-to-creatinine ratio (UACR). This simple urine test looks for albumin, a protein that healthy kidneys keep in the blood. Albumin leaking into the urine is often one of the earliest signs of kidney damage — sometimes appearing even when eGFR is still normal.

Doctors look at both numbers together. Two people with the same eGFR can have very different risk depending on how much albumin is in their urine.

Who Should Be Screened

You don’t need to wait for symptoms. Regular kidney testing is recommended for people with:

• Diabetes
• High blood pressure
• Heart disease
• A family history of kidney disease
• Obesity
• Older age

Diabetes and high blood pressure together cause the majority of kidney disease in the United States.

Symptoms Usually Come Late

When symptoms do appear, they tend to be vague: swelling in the ankles or around the eyes, fatigue, foamy urine, changes in how often you urinate, itching, poor appetite, or trouble concentrating. By that point, a significant amount of function may already be lost. That’s the case for testing early.

Things That Can Affect Your Results

A single result isn’t always the whole story. Dehydration, a recent intense workout, eating a lot of meat before the test, certain medications, and a urinary infection can all shift numbers temporarily. That’s why abnormal results are typically repeated before a diagnosis is made.

Protecting Your Kidneys

• Keep blood pressure in your target range. This is one of the most powerful steps you can take.
• Manage blood sugar if you have diabetes or prediabetes.
• Be cautious with over-the-counter pain relievers like ibuprofen and naproxen. Regular use can harm the kidneys, especially if you already have reduced function. Ask your doctor what’s safe for you.
• Stay hydrated, unless you’ve been told to limit fluids.
• Don’t smoke, and keep up regular physical activity.
• Review your medications. Some need dose adjustments when kidney function is lower.

Treatment Has Come a Long Way

For people with kidney disease, especially alongside diabetes, newer medications can slow its progression and also lower heart risk. These are decisions to make with your doctor based on your full health picture.

Know Your Numbers

Next time you get bloodwork, ask what your eGFR is and whether your urine has been checked for albumin. Knowing your numbers — and how they change over time — is one of the simplest ways to protect your kidneys for decades to come.

This article is for general education and isn’t a substitute for medical advice. If you have symptoms that are severe, sudden, or worrying, call 911 or seek emergency care.