Living with chronic kidney disease (CKD) often means tracking multiple lab values, and for good reason. Your kidneys affect nearly every system in your body, so when they’re not working as well, the impact goes far beyond just “kidney numbers.”*

Understanding your labs can help you:

• Follow how your disease is progressing
• Catch potential complications early
• Make more informed decisions with your care team
• Stay engaged and proactive in your treatment plan

Important:

Everybody’s situation is different, some of these tests may not apply to you. Similarly, your situation may require tests that are not included here. Also, having results outside the “normal” range listed on your lab report does not always mean there is a problem.

Your healthcare provider will interpret your results based on your overall health, medical history, and CKD stage, so always discuss any concerns with them before making changes.

The role of our kidneys

We have two kidneys that filter blood, which is cleaned and recollected, then redirected to our renal veins. The product of the filtration process, which is composed of excess waste and fluids, is excreted as urine. 

In essence, the kidneys:

• Clean the blood to maintain normal blood composition
• Get rid of excess fluid
• Reclaim substances that the body needs
• Produce erythropoietin, a hormone enabling the body to make new red blood cells
• Activate vitamin D, which is important for immune and bone health

Kidney function: your most important numbers

Estimated glomerular filtration rate

The estimated glomerular filtration rate (eGFR) measures how well the blood is being filtered by the kidneys. Your eGFR is calculated using your creatinine levels, age, race, and gender. A GFR above 60, and a creatinine number below 1.2, are considered “good.” Learn more about eGFR in our blog post.

Depending on eGFR levels, patients are diagnosed with CKD stage 1, 2, 3, 4, or 5 (known as end-stage renal disease).

Creatinine

Creatinine is a waste product created by normal muscle activity. Healthy kidneys remove it from the blood.

• Higher creatinine levels may indicate reduced kidney function
• Levels can vary based on muscle mass, age, diet, and medications

Creatinine can stay “normal” even when kidney function is declining, especially early on. That’s why it’s used together with eGFR, not alone.

Urine albumin-to-creatinine ratio (uACR)

This test measures how much protein (albumin) is leaking into your urine.

• Normal: less than 30 mg/g
• Higher levels may indicate kidney damage

Healthy kidneys keep protein in your blood, not in your urine. Even small increases in uACR can be an early warning sign of CKD.

Monitoring your overall health

Blood pressure

Blood pressure and kidney health are tightly connected.

• High blood pressure can damage kidney blood vessels
• Kidney disease can also cause blood pressure to rise

Keeping blood pressure in range is one of the most effective ways to slow CKD progression.

Your target may vary depending on age, other conditions (like diabetes) or risk of falls or dizziness.

Weight

Your weight gives important clues about your overall health and fluid balance.

• Gradual weight gain → may reflect diet or lifestyle
• Sudden weight gain → could signal fluid buildup
• Unintentional weight loss → may indicate poor nutrition

For patients on dialysis or with heart issues, tracking your “dry weight” (your weight without extra fluid) is especially important.

Metabolic complications: what happens as CKD progresses

As kidney function declines, your body may struggle to maintain balance in key systems.

Anemia (low red blood cells)

Your kidneys produce a hormone that helps your body make red blood cells. When kidney function drops, anemia can develop.

Common labs:

• Hemoglobin
• Hematocrit
• Iron levels (ferritin, TSAT)

Symptoms may include:

• Fatigue
• Weakness
• Shortness of breath

Treating anemia can significantly improve energy levels and quality of life.

Potassium

Potassium is essential for heart and muscle function, but it must stay in a tight range.

• High potassium (hyperkalemia) can affect heart rhythm
• Low potassium can cause weakness and muscle issues

As kidney function declines, your body may have trouble removing excess potassium. Learn more about potassium, and other important nutrients and kidney health here.

Acidosis (low bicarbonate / CO₂)

Healthy kidneys help keep your blood from becoming too acidic. Low bicarbonate levels may indicate metabolic acidosis, which can contribute to muscle loss, speed up CKD progression. This is often treatable with medication.

Bone and mineral disorder (CKD-MBD)

Your kidneys help regulate:

• Calcium
• Phosphorus
• Vitamin D
• Parathyroid hormone (PTH)

When these are out of balance, it can lead to weak bones, calcium buildup in blood vessels and hormonal changes.

Additional labs that complete the picture

Blood urea nitrogen (BUN)

Another waste product your kidneys remove.

• Higher levels may indicate reduced kidney function
• Best interpreted alongside creatinine and eGFR

Cystatin C

An alternative marker of kidney function.

• Sometimes used for a more accurate eGFR estimate
• Less influenced by muscle mass than creatinine

Blood sugar (A1C, glucose)

Diabetes is the leading cause of CKD.

• A1C reflects average blood sugar over 2–3 months
• High levels increase risk of kidney damage

Cholesterol

CKD increases the risk of heart disease. Your doctor may monitor:

• LDL (“bad” cholesterol)
• HDL (“good” cholesterol)
• Triglycerides

Heart disease is one of the most common complications of CKD, so it’s important to keep track of your cholesterol.

What your results really mean

This is where things often get confusing, and where many patients start to feel overwhelmed.

You get your lab results back, you see something flagged in red, and it’s easy to jump straight to worry. But the reality is a bit more nuanced.

A single abnormal result doesn’t tell the whole story. Lab values can fluctuate for many reasons: hydration, recent meals, medications, even timing. One number, taken on its own, rarely defines your health or your kidney function.

On top of that, those “normal ranges” listed on your lab report aren’t always designed for people living with CKD. What’s considered “normal” for the general population may not apply to you—and that’s okay. Your care team is looking at your results through a different lens.

What matters most is how your numbers change over time. Are they stable? Improving? Slowly declining? These trends give your doctor a much clearer picture of what’s happening and how your condition is progressing.

And most importantly, your targets are personal. Your ideal blood pressure, eGFR range, potassium level, or A1C goal may be different from someone else’s based on your stage of CKD, other health conditions, and overall risk profile.

In simple terms: your lab results aren’t a one-time snapshot—they’re a story unfolding over time. The goal isn’t perfection. It’s understanding the direction your health is moving and making the right adjustments along the way.

Take control of your kidney health

Understanding your numbers helps you become an active partner in your care. Consider asking your doctor:

• Which lab values matter most for me right now?
• What are my personal target ranges?
• Are my numbers stable, improving, or declining?
• What changes (if any) should I make?

*National Kidney Foundation.” (September 05, 2023). “Understanding your lab values and other CKD health numbers”. kidney.org

The Information provided by Responsum Health is for educational purposes only and does not replace professional medical advice. Always talk with your healthcare provider before making changes to your treatment or care. Responsum Health does not endorse specific treatments, providers, or products.