Kidney Function Tests (RFTs)
Start with the big picture
RFTs include serum analytes such as creatinine, urea, uric acid, electrolytes, calcium, and phosphate, alongside measures of filtration, urine composition, and kidney-related hormonal activity. Estimated GFR and creatinine clearance help assess filtration; cystatin C offers an estimate less dependent on muscle mass. Urine albumin-to-creatinine ratio, sediment, specific gravity, and osmolality provide complementary information about kidney injury and tubular or concentrating function. Electrolyte and bicarbonate results can help identify disturbances associated with renal disease. No single result tells the whole story: factors such as protein catabolism, liver function, diet, medicines, and muscle mass can affect interpretation. The full lesson organizes these tests by function and clinical relevance.
What you'll learn
- Identify the main serum analytes used in renal function assessment.
- Describe how eGFR, creatinine clearance, and cystatin C assess filtration.
- Recognize urine markers used to assess albuminuria and tubular function.
- Relate electrolyte, bicarbonate, and hormonal findings to kidney function.
- Explain why clinical context matters when interpreting creatinine and urea.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
