RENAL FUNCTION TESTS
Renal function tests are used to evaluate the severity of kidney disease and to assess the patient’s clinical progress. These tests also provide information on the effectiveness of the kidney in carry-ing out its excretory function. Renal function test results may be within normal limits until the GFR is reduced to less than 50%of normal. Renal function can be assessed most accurately if sev-eral tests are performed and their results analyzed together. Com-mon tests of renal function include renal concentration tests, creatinine clearance, and serum creatinine and blood urea nitro-gen levels. Table 43-4 describes the purpose and normal ranges for each. Other helpful tests for evaluating renal function are serum electrolyte levels.