Assessment of kidney function occurs in different ways, using the presence of symptoms and signs, as well as measurements using urine tests, blood tests, and medical imaging.
Functions of a healthy kidney include maintaining a person's fluid balance, maintaining an acid-base balance; regulating electrolytes including sodium, potassium, and other electrolytes; clearing toxins; regulating blood pressure; and regulating hormones, such as erythropoietin; and activation of vitamin D.[citation needed]