Kidney Function Tests: Serum Creatinine, BUN, GFR, and Electrolytes

Serum creatinine is the primary chemistry test for kidney function. Elevated levels indicate reduced filtration.

Complementary Tests

• Blood Urea Nitrogen (BUN): Protein waste product; rises with kidney dysfunction (also affected by hydration, protein intake).
• Glomerular Filtration Rate (GFR): Calculated from creatinine, age, sex, race; best overall function estimate (normal >90 mL/min/1.73m²).
• Electrolytes: Sodium, potassium, chloride, bicarbonate—imbalances signal renal tubular dysfunction.
• Uric Acid: Elevated in reduced excretion; also seen in gout, tumor lysis.

Test selection depends on clinical context. Serial monitoring tracks disease progression and treatment response.