What labs are included in a renal panel?

Renal Panel Components

A renal panel typically includes blood urea nitrogen (BUN), serum creatinine, electrolytes (sodium, potassium, chloride, bicarbonate), and estimated glomerular filtration rate (eGFR) as the core components for assessing kidney function. 1

Core Laboratory Tests

The essential components of a standard renal panel include:

• Blood Urea Nitrogen (BUN): A waste product filtered by the kidneys that reflects both renal function and hydration status 1, 2
• Serum Creatinine: The most reliable single indicator of kidney function, as it is a waste product from muscle metabolism that is filtered exclusively by the kidneys 1, 2
• Estimated Glomerular Filtration Rate (eGFR): A calculated value based on creatinine levels that estimates how efficiently the kidneys filter blood, with normal values typically >60 mL/min/1.73m² 1, 3
• Electrolytes: Sodium, potassium, chloride, and bicarbonate (CO2) are routinely included to assess electrolyte balance and acid-base status 1, 3

Additional Components Frequently Included

Many comprehensive metabolic panels that serve as renal panels also contain:

• Calcium and Phosphorus: Important for bone health and frequently affected by kidney disease 1
• Albumin: A major blood protein that indicates nutritional status and can reflect kidney function 1

Enhanced Assessment for CKD Diagnosis

For accurate CKD diagnosis and staging, KDIGO guidelines recommend a "triple marker" panel consisting of serum creatinine, serum cystatin C, and urine albumin-to-creatinine ratio (UACR). 3

• Cystatin C: Should be used in combination with creatinine (eGFRcr-cys) for more accurate GFR estimation, particularly in patients with eGFR 45-59 mL/min/1.73m² by creatinine alone, as this reclassifies over 40% of patients 3
• Urine Albumin-to-Creatinine Ratio (UACR): Essential for detecting kidney damage and risk stratification, as albuminuria independently predicts cardiovascular events, kidney failure, and mortality 3

Clinical Interpretation Priorities

eGFR is the preferred initial assessment of kidney function, with values <60 mL/min/1.73m² indicating potential chronic kidney disease that requires confirmation with repeat testing. 1, 3

• The BUN-to-creatinine ratio helps distinguish prerenal from intrinsic renal causes of dysfunction 2
• Serum creatinine is less influenced by extrarenal factors than BUN, making it more accurate for assessing true kidney function 2
• Reproducibility of creatinine measurement is within 2% 2

Common Pitfalls to Avoid

• Do not rely on a single abnormal eGFR or creatinine value: Repeat testing is required to confirm chronicity (duration of at least 3 months) and exclude acute kidney injury 3
• Do not assess eGFR without measuring albuminuria: Both markers are essential for proper CKD screening, diagnosis, and risk stratification 3
• Consider cystatin C testing when eGFR by creatinine is borderline: This prevents misclassification, particularly in older adults with eGFR 45-59 mL/min/1.73m² 3