Recipient(s) will receive an email with a link to 'Creatinine Clearance (CrCl)' and will have access to the topic for 7 days.
Subject: Creatinine Clearance (CrCl)
(Optional message may have a maximum of 1000 characters.)
This test compares the creatinine in a 24-hour sample of urine to the creatinine level in the blood to show how much blood the kidneys are filtering out each minute. It is calculated by the formula:
Male: 90–139 mL/minute
Female: 80–125 mL/minute
Evaluate glomerular function
Monitor effectiveness of treatment in renal disease
Acute tubular necrosis
Exposure to nephrotoxic drugs and chemicals
Neoplasms (bilateral renal)
Polycystic kidney disease
Renal artery atherosclerosis and obstruction
Renal vein thrombosis
Shock and hypovolemia
Acute or chronic GN
Chronic bilateral pyelonephritis
Muscle wasting diseases
Urinary tract obstruction (e.g., from calculi)
CrCl approximates GFR but overestimates it due to the fact that creatinine is secreted by the proximal tubule as well as filtered by the glomerulus.
Measurement of CrCl should be considered in circumstances when the estimating equation based on serum creatinine is suspected to be inaccurate or for patients with estimated GFR >60 mL/minute/1.73 m2 when a more accurate clearance measure is required for clinical decision making. Such circumstance may occur in people who are undergoing evaluation for kidney donation, treatment with drugs with significant toxicity that are excreted by the kidneys (e.g., high-dose methotrexate), or consideration for participation in research protocols.
Indications for a clearance measurement because estimates based on serum creatinine may be inaccurate because of extremes of age and body size, severe malnutrition or obesity, disease of skeletal muscle, paraplegia or quadriplegia, a vegetarian diet, rapidly changing kidney function, or pregnancy.
Drugs that may increase urine CrCl include enalapril, oral contraceptives, prednisone, and ramipril.
Drugs that may decrease the urine CrCl include acetylsalicylic acid, amphotericin B, carbenoxolone, chlorthalidone, cimetidine, cisplatin, cyclosporine, guancydine, ibuprofen, indomethacin, mitomycin, oxyphenbutazone, paromomycin, probenecid (coadministered with digoxin), and thiazides.
Excessive ketones in urine may cause falsely decreased values.
Failure to follow proper technique in collecting 24-hour specimen may invalidate test results.
Failure to refrigerate the specimen throughout the urine collection period allows decomposition of creatinine, causing falsely decreased values.
Consumption of large amounts of meat, excessive exercise, and stress should be avoided for 24 hours before the test.