Kidney health is often overlooked until there’s a problem, but regular kidney function tests are crucial in identifying early signs of kidney disease. These tests help physicians determine how well your kidneys are performing their essential tasks, such as filtering waste from your blood, balancing fluids, and regulating blood pressure.
Understanding your kidney function test results can be confusing, but it’s important to decode them so you can make informed decisions about your health. In this post, we will break down the key components of kidney function tests and explain what they mean for you.
Why Kidney Function Tests Matter
Your kidneys filter approximately 50 gallons of blood every day, removing waste, toxins, and excess fluid. When kidney function declines, these waste products can build up in the body, leading to serious health complications, including high blood pressure, anemia, and bone disease.
Regular kidney function tests can help detect early-stage kidney disease, often before symptoms appear. These tests are especially important for individuals with risk factors such as diabetes, hypertension, or a family history of kidney disease.
Types of Kidney Function Tests
There are several tests your healthcare provider may use to evaluate kidney function. The most common tests include:
- Blood Tests:
- Serum Creatinine: This test measures the level of creatinine, a waste product produced by muscles, in your blood. Elevated levels of creatinine can indicate that your kidneys are not filtering it properly.
- Blood Urea Nitrogen (BUN): This test measures the amount of urea nitrogen in your blood, a waste product that your kidneys remove. High levels of BUN can be a sign of kidney dysfunction, but they can also be influenced by other factors such as dehydration or a high-protein diet.
- Urine Tests:
- Urine Albumin-to-Creatinine Ratio (ACR): This test measures the amount of protein (albumin) in your urine. Healthy kidneys do not usually allow protein to leak into urine, so high levels of albumin can indicate kidney damage or disease.
- 24-Hour Urine Test: This test measures the amount of creatinine cleared from the blood by your kidneys over a 24-hour period. It can help assess kidney function and diagnose conditions like chronic kidney disease (CKD).
- Estimated Glomerular Filtration Rate (eGFR): The eGFR is a key test for assessing kidney function. It estimates how well your kidneys are filtering blood based on your serum creatinine level, age, sex, and ethnicity. A normal eGFR is typically above 90 mL/min/1.73m², but a value below 60 can be a sign of kidney disease.
Key Kidney Function Test Results and What They Mean
Now, let’s break down what your test results could mean.
- Serum Creatinine
- Normal Range: 0.6 to 1.2 mg/dL (for adults)
- What It Means: A higher than normal creatinine level suggests that your kidneys may not be filtering waste properly. Elevated creatinine levels can be caused by a variety of factors, including kidney disease, dehydration, or high-protein diets.
- What to Do: If your creatinine levels are elevated, your doctor may order additional tests to determine the cause. Treatment may involve managing underlying conditions like diabetes or hypertension, or in some cases, medications to help protect kidney function.
- Blood Urea Nitrogen (BUN)
- Normal Range: 7 to 20 mg/dL
- What It Means: BUN is affected by many factors, such as protein intake, dehydration, and kidney function. Elevated BUN levels can indicate kidney dysfunction, but they may also be due to factors unrelated to kidney health, such as gastrointestinal bleeding or a high-protein diet.
- What to Do: If your BUN levels are high, it’s important to consider other potential causes, like dehydration. Your doctor may recommend additional tests or a change in diet to address the underlying cause.
- Urine Albumin-to-Creatinine Ratio (ACR)
- Normal Range: Less than 30 mg/g
- What It Means: An elevated ACR indicates protein in your urine, which is a sign of kidney damage. If left untreated, this condition can progress to chronic kidney disease. An ACR above 30 mg/g is a cause for concern.
- What to Do: If your ACR is elevated, your doctor will likely recommend lifestyle changes, such as controlling blood sugar and blood pressure, and may prescribe medications like ACE inhibitors or ARBs to reduce proteinuria (protein in urine).
- Estimated Glomerular Filtration Rate (eGFR)
- Normal Range: 90 or above
- What It Means: The eGFR is a key indicator of kidney health. A decrease in eGFR below 60 mL/min/1.73m² for three months or more is a sign of chronic kidney disease. The eGFR decreases naturally with age, but a significant drop could indicate kidney problems.
- What to Do: If your eGFR is low, it’s important to follow up with your healthcare provider. They may recommend additional tests to assess the extent of kidney damage and may provide treatment options to slow the progression of kidney disease.
Understanding Kidney Disease Stages
Kidney disease is classified into five stages based on your eGFR and other factors. Here’s a quick overview:
- Stage 1 (Normal Kidney Function): eGFR of 90 or above, but there may still be signs of kidney damage (e.g., protein in urine).
- Stage 2 (Mild Kidney Damage): eGFR of 60–89, with mild damage to the kidneys.
- Stage 3 (Moderate Kidney Damage): eGFR of 30–59, with noticeable kidney damage. You may start to experience symptoms like fatigue, swelling, or high blood pressure.
- Stage 4 (Severe Kidney Damage): eGFR of 15–29. At this stage, kidney function is severely compromised, and dialysis or a kidney transplant may be considered.
- Stage 5 (End-Stage Kidney Failure): eGFR below 15. This is when the kidneys can no longer maintain normal function, and dialysis or a kidney transplant is necessary.
What Can You Do to Protect Your Kidneys?
If you’ve received results indicating a decline in kidney function, there are several lifestyle changes you can make to help protect your kidneys:
- Control Blood Pressure: High blood pressure can damage the kidneys over time. Aim for a healthy blood pressure below 130/80 mm Hg.
- Manage Diabetes: High blood sugar can damage blood vessels in the kidneys, leading to kidney disease. Keeping blood sugar levels in check is crucial.
- Stay Hydrated: Dehydration can put a strain on your kidneys. Drink plenty of water throughout the day.
- Avoid Smoking: Smoking slows blood flow to the kidneys and accelerates kidney damage.
- Limit Salt Intake: Too much sodium can increase blood pressure and worsen kidney function.
- Exercise Regularly: Staying active helps maintain a healthy weight and reduce the strain on your kidneys.
When to Seek Medical Help
If your kidney function test results indicate kidney disease or if you are at risk for kidney problems, it’s important to work closely with your healthcare provider. Early detection and intervention can significantly slow the progression of kidney disease and improve your quality of life. If you experience any of the following symptoms, it’s important to seek medical attention:
- Swelling in your legs, ankles, or feet
- Fatigue or weakness
- Difficulty urinating or changes in urination patterns
- Unexplained nausea or vomiting
- Shortness of breath or chest pain
Decoding your kidney function test results is essential to understanding your kidney health. By staying informed about these tests and their implications, you can take proactive steps to protect your kidneys and prevent further damage. Regular check-ups and lifestyle modifications can make a significant difference in the long-term health of your kidneys.
If you have any concerns about your kidney function or need guidance on interpreting your results, don’t hesitate to reach out to your healthcare provider or the experts at Durham Nephrology. We are here to support you on your journey toward better kidney health.
