Key Medical Tests and Lab Results

If you have been diagnosed with kidney disease, your doctor will likely order various tests to monitor your kidney function and overall health. Understanding these tests can help you feel more in control of your care. Here's a breakdown of the key medical tests and what their results mean.

Blood Tests

1. Serum Creatinine

   What it measures: The creatinine level, a waste product from muscle metabolism, in your blood.

   Why it matters: High creatinine levels indicate that your kidneys aren't filtering waste effectively.

   Normal range:

   1. Men: 0.7 to 1.3 mg/dL

   2. Women: 0.6 to 1.1 mg/dL

2.  eGFR (Estimated Glomerular Filtration Rate)

   What it measures: How well your kidneys filter waste from your blood.

   Why it matters: eGFR helps determine the stage of kidney disease.

   Normal range: 90 mL/min/1.73 m² or higher. Lower values indicate reduced kidney function.

3. Blood Urea Nitrogen (BUN)

   What it measures: The amount of urea nitrogen, another waste product, in your blood.

   Why it matters: High BUN levels may indicate reduced kidney function.

   Normal range: 7 to 20 mg/dL.

4. Electrolytes (Sodium, Potassium, Calcium, Phosphorus)

5. Why they matter: Electrolyte imbalances are common in kidney disease and can affect brain, heart and muscle function.

6. Key values to watch:

   • Sodium: 135-145 mmol/L

   • Potassium: 3.5-5.0 mmol/L (High potassium can harm the heart.)

   • Calcium: 8.5-10.5 mg/dL

   • Phosphorus: 2.5-4.5 mg/dL (High phosphorus can lead to bone problems.)

5. Hemoglobin and Hematocrit

6. What they measure: The amount of hemoglobin (a protein in red blood cells) and the percentage of red blood cells in your blood.

7. Why it matters: Low levels may indicate anemia, a common complication of kidney disease.

8. Normal range:

   • Hemoglobin: 13.5-17.5 g/dL (men), 12.0-15.5 g/dL (women)

   • Hematocrit: 38.3-48.6% (men), 35.5-44.9% (women)

Urine Tests

1. Urine Protein/Creatinine Ratio (UPCR)

   What it measures: The amount of protein in your urine relative to creatinine.

   Why it matters: High protein levels in the urine (proteinuria) indicate kidney damage.

   Normal range: Less than 150 mg of protein per day.

2. Urinalysis

   What it measures: The presence of protein, blood, and other substances in your urine.

   Why it matters: It helps detect signs of kidney damage, infection, or other abnormalities.

3. 24-Hour Urine Collection

   What it measures: The total amount of urine produced in 24 hours and the amount of protein and waste products.

   Why it matters: It provides a more accurate picture of kidney function and protein loss.

Imaging Tests

1. Ultrasound

   What it shows: Your kidneys' size, shape, and structure.

   Why it matters: It can detect kidney stones, cysts, or structural abnormalities.

2. CT Scan or MRI

   What they show: Detailed images of your kidneys.

   Why they matter: These tests can identify tumors, blockages, stones, cysts or other kidney function issues.

3. Kidney Biopsy

   What it involves: Removing a small sample of kidney tissue for examination under a microscope.

   Why it matters: It helps diagnose specific types of kidney disease and guides treatment.

Additional Specialized Tests

1. Parathyroid Hormone (PTH)

   What it measures: The level of PTH, a hormone that regulates calcium and phosphorus levels.

   Why it matters: High PTH levels can occur in kidney disease and lead to bone problems.

2. Vitamin D Levels

   Why it matters: Kidney disease can lead to low active vitamin D levels, affecting bone health.

3. Cystatin C

   What it measures: A protein that may provide a more accurate estimate of kidney function than creatinine in some cases.

How to Understand Your Lab Results

1. Know Your Baseline: Everyone's normal values can vary slightly. To track changes, keep a record of your test results over time.

2. Focus on Trends: A single abnormal result may not be significant, but consistent changes over time can indicate a problem.

3. Ask Questions: Don't hesitate to ask your healthcare provider to explain your results and what they mean for your condition.

4. Work with Your Healthcare Team: Your nephrologist, dietitian, and primary care physician can help you understand your results and make necessary lifestyle changes.

Questions to Ask Your Doctor

• What do my current test results mean for my kidney function?

• How often should I have these tests done?

• Are there specific steps I can take to improve my test results?

• What are the warning signs that I should watch for between tests?

Takeaway

Regular testing is essential for managing kidney disease. Understanding your lab results can help you actively participate in your care and work closely with your healthcare team to protect your kidney health. By knowing what each test measures and why it matters, you can better track your condition and make informed decisions about your treatment.