Your kidneys are incredible filters, but how do we know if they’re working well? That’s where your lab report comes in. It can be hard to know what’s what on your report, so we’ll go over six key kidney lab tests.
1. eGFR (estimated Glomerular Filtration Rate)
The eGFR is your most critical filtration score—it estimates how many milliliters of blood your kidneys clean per minute. This number directly corresponds to the five stages of Chronic Kidney Disease (CKD). While your eGFR is estimated using a formula based on creatinine, age, and sex, it’s the standard for classifying the severity of kidney disease. Your doctor monitors this number to track the stability or progression of any damage.
Reading the Results
A great score is anything above 90. If your score is below 60, that means it’s time to talk to your doctor.
2. Creatinine
Creatinine comes from the breakdown of muscle tissue. High levels suggest your kidneys aren’t clearing this waste properly, but that doesn’t always tell the whole story. A young bodybuilder will naturally have a high creatinine level, which might suggest kidney trouble, even if their kidneys are fine! It can also give a misleading picture to those who are older or more frail, which is why this test is coupled with Cystatin C.
3. Cystatin C
Your levels of Cystatin C (a protein produced by almost every cell in the body) are a more “universal” marker because they are less influenced by age or muscle mass. This gives doctors a more accurate and sometimes earlier detection of kidney issues.
4. BUN (Blood Urea Nitrogen)
This test checks for protein waste (urea) levels in your blood. A high reading can signal two things: either dehydration (the most common cause) or that the kidneys are having trouble filtering protein waste. If your BUN is high, your doctor will usually check other labs (like Creatinine) and ask about your fluid intake before jumping to a kidney disease diagnosis.
5. ACR (Albumin-to-Creatinine Ratio)
An albumin to creatinine ratio (ACR) test checks for protein in your urine and helps identify kidney disease relating to diabetes. Too much protein is usually a sign of kidney damage and should be evaluated by a nephrologist.
Reading the Results
- A low ACR usually means your kidneys are functioning normally.
- A high ACR suggests you may have early-stage kidney damage, which may require further monitoring or treatment to prevent it from getting worse.
6. Genetic Testing
Genetic testing looks at your DNA for specific genetic causes of kidney disease. This helps your doctor identify inherited conditions, like Polycystic Kidney Disease (PKD). Understanding these underlying conditions allows for personalized treatment plans.
Personalized Treatment & Next Steps
These six tests help your care team understand your kidneys and personalize your treatment, whether that means diet changes, medication, or further monitoring.
Explore kidney health options and find a nephrologist near you today.
