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ID:352 Creatinine Clearance
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DescriptionA 24 hr Urine collection in a plain specimen bottle is also required. Blood should be taken during the course of the urine collection. This test is NOT recommended as a routine assay due to variability of results.
IndicationMeasurement of creatinine clearance provides an indication of GFR and is useful in assesment of renal function, particularly the early stages of CRF when plasma creatinine may be within reference range.
Additional InfoCreatinine is a waste product of muscle metabolism which is excreted in urine. Creatinine is neither secreted nor reabsorbed to any significant quantity by the renal tubules and hence the relationship between the urinary excretion of creatinine and its plasma concentration can be used as a measure of the GFR. Creatinine clearance is calculated as follows: clearance = UV / P where P = plasma creatinine concentration, U = urine creatinine concentration, and V = rate of flow (V = urine volume / time). CORRECTION FACTOR FOR CHILDREN: Normal creatinine clearance is lower in children because of their smaller muscle mass but it can be expressed in terms of the average adult body surface area of 1.73 m2 by using the following formulae: (creatinine clearance X 1.73) / surface area (m2) which is = [(creatinine clearance X 1.73) X (weight + 90)] / [7+(weight X 4)] where weight is in Kg. Day to day variation in creatinine clearance is about 10%.
Concurrent Testsna
Dietary Requirementsna
InterpretationCreatinine clearance is a measure of the GFR, which has to fall by 50% before a significant rise in serum creatinine is seen.

DepartmentBiochemistry
SampleBlood
TubeSerum or Heparin
Tube Picture
Collection Conditions
Min. Vol1 mL
Freq.Weekdays

Ref. Range (Male)95 - 140
Ref. Range (Female)85 - 125
Ref. Range (Paed)
Ref. Range Notes
UnitsmL/min
IP Acute TATRefer to Website
IP Routine TATRefer to Website
GP Acute TAT- Contact Laboratory
GP Routine TATRefer to Website
Turnround CommentNA

Originally edited by : . Review due on 15/04/2014 14:23:46. Published By Sylvia Bennett on 15/04/2013 14:23:46.