CKD Lab Results Explained: GFR, Creatinine & More

Why Understanding Your Labs Changes Everything

Lab results can feel like a foreign language. Yet each number tells part of your kidney story — and understanding the basics helps you ask better questions at appointments.

GFR — The Number That Defines Your Stage

Estimated glomerular filtration rate (eGFR) measures how well your kidneys filter waste. CKD is staged by eGFR and other markers of kidney damage. A single lab value can fluctuate with hydration, illness, or medication — trends over time matter more than one reading.

Creatinine — The Waste Product Your Kidneys Filter

Creatinine is a byproduct of muscle metabolism. When kidney function declines, creatinine often rises in the blood. Your care team interprets creatinine alongside eGFR, age, sex, and body size.

Potassium — The Lab That Demands Immediate Attention

High potassium (hyperkalemia) can affect heart rhythm. Call your care team promptly if you have symptoms such as palpitations or weakness, or if you receive an urgent lab notification.

Phosphorus — The Silent Cardiovascular Risk

Elevated phosphorus in CKD is linked to bone and vascular complications over time. Diet, binders, and dialysis (when applicable) are all part of management — under physician supervision.

Keto Nephron™ DS is formulated with phosphorus content within ranges appropriate for CKD dietary management — a consideration for patients working with their nephrologist on phosphorus-related nutritional goals.

BUN (Blood Urea Nitrogen)

BUN reflects protein metabolism and hydration status. It rises when kidney clearance falls or when protein intake is high relative to kidney function.

Hemoglobin / Hematocrit — CKD-Related Anemia

Many CKD patients develop anemia as kidney-produced erythropoietin declines. Fatigue from anemia can overlap with other CKD symptoms — your nephrologist can distinguish causes.

How Nutrition Affects Your Labs

Diet influences potassium, phosphorus, BUN, and nutritional status markers. Patients often ask whether there is a nutritional product designed to work within CKD's strict parameters. Keto Nephron™ DS is a medical food formulated for the dietary management of CKD stages 3–5 — it provides essential nutrients, including protein, while controlling phosphorus, potassium, and sodium within CKD-appropriate parameters. It must be used under physician supervision and is not a substitute for medical treatment.

Questions to Ask Your Nephrologist at Your Next Visit

• What is my eGFR trend over the past 12 months?
• Which labs should I track most closely at my stage?
• Is my current nutritional plan appropriate for my potassium and phosphorus goals?