Understanding Kidney Function Tests: sCr, eGFR, ACR and BUN

Author: Krishan Kumar Singh, Senior Product Manager, Peerless Biotech Pvt. Ltd. (A Subsidiary of Entero Healthcare Solutions Ltd.)

Your kidneys are incredible organs that keep your body healthy by filtering waste and balancing fluids. But how do you know if your kidneys are doing their job? Doctors use a few important tests to check how well your kidneys are working and to spot any signs of trouble early on. Let’s break these tests down into simple terms so you can understand them better.

1. Serum Creatinine (sCr): A Simple Blood Test

Creatinine is a waste product that comes from your muscles. Healthy kidneys filter creatinine out of your blood and send it out of your body in urine. If your kidneys aren’t working well, creatinine builds up in your blood.

• What’s Normal? For most women, a level above 1.2 mg/dL, and for most men, a level above 1.4 mg/dL, might mean your kidneys need some attention. However, what’s normal can depend on your age, body size and other factors.
• Why It’s Important: This test gives doctors a quick idea of how well your kidneys are filtering waste.

2. eGFR (Estimated Glomerular Filtration Rate): A Deeper Look

The eGFR is like a calculation that uses your creatinine levels, age, gender and sometimes race to figure out how well your kidneys are filtering waste. It’s more specific than just looking at creatinine alone.

• What’s Normal? A value of 90 or above is good, but if your eGFR drops below 60, it could mean chronic kidney disease. If it goes below 15, your kidneys might need extra help, like dialysis or a transplant.
• Why It Matters: eGFR helps catch kidney problems early and can guide treatment.

3. Albumin-to-Creatinine Ratio (ACR): Checking Your Urine

This test looks for a protein called albumin in your urine. Healthy kidneys don’t let much albumin pass through, so finding it in urine can be a sign of kidney damage.

• What’s Normal? An ACR below 30 mg/g is normal. Between 30-300 mg/g shows mild damage and above 300 mg/g means more serious problems.
• Why It’s Useful: It’s a simple way to spot early signs of kidney damage and take action.

4. BUN (Blood Urea Nitrogen): Another Blood Test

BUN measures how much urea nitrogen is in your blood. This waste product comes from breaking down protein in the food you eat.

• What’s Normal? A BUN level between 7 and 20 mg/dL is typical. Higher levels could mean your kidneys aren’t filtering waste well, but other things like dehydration or certain medications can also raise BUN.
• Why Doctors Use It: It’s one piece of the puzzle to understand kidney function.

Why Should You Care?

Kidney disease can sneak up on you because it often has no symptoms in the early stages. These tests can catch problems early, giving you a chance to slow or even stop kidney damage.

How to Keep Your Kidneys Healthy

You can take steps to protect your kidneys:

• Drink water: Stay hydrated but don’t overdo it.
• Eat smart: Cut back on salt and processed foods. Choose fresh fruits and vegetables.
• Control your blood pressure and blood sugar: High blood pressure and diabetes are major causes of kidney problems.
• Avoid smoking and limit alcohol: These habits can damage your kidneys over time.
• Stay active: Regular exercise supports overall health, including your kidneys.

Take Action Today

If you’ve never had your kidney function checked, ask your doctor about it, especially if you have diabetes, high blood pressure, or a family history of kidney problems. Knowing your numbers could make a big difference in your health.

Kidney health is vital for your overall well-being. By understanding these tests and taking care of your body, you can give your kidneys the support they need to keep you feeling your best. Got questions? Drop them in the comments—let’s talk about it!