Renal Function Tests

The kidneys play a vital role in the excretion of waste products and toxins such as urea, creatinine and uric acid, regulation of extracellular fluid volume, serum osmolality and electrolyte concentrations, as well as the production of hormones like erythropoietin and 1,25 dihydroxy vitamin D and renin. The functional unit of the kidney is the nephron, which consists of the glomerulus, proximal and distal tubules, and collecting duct. Assessment of renal function is important in the management of patients with kidney disease or pathologies affecting renal function. Tests of renal function have utility in identifying the presence of renal disease, monitoring the response of kidneys to treatment, and determining the progression of renal disease. According to the National Institutes of Health, the overall prevalence of chronic kidney disease (CKD) is approximately 14%. Worldwide, the most common causes of CKD are hypertension and diabetes.This article provides an update on the relevant biochemical tests for the assessment of renal function.