Creatinine clearance is used as an index of glomerular filtration rate (GFR). Although this produces an over estimate of the GFR due to a small amount of creatinine being excreted by the tubules, it has the advantage over other substances (e.g inulin) in that it is a natural metabolite.
Creatinine clearance decreases as renal function fails. It is used to monitor various renal diseases and allows the clinician to decide at what stage renal dialysis is essential.
Pharmacologically creatinine clearance is of help in managing the dosage of potentially toxic drugs which are cleared by the kidney.
The Radiography department occasionally requires creatinine clearance results urgently before administering cyto-toxic drugs.
Male: 85 – 125 mL/min
Female: 75 – 115 mL/min
- This test requires a 24 hour urine collection in a plain bottle and also a Serum or Lithium Heparin Plasma sample taken during that 24 hour period.
- The urine volume is measured and recorded on the request form.