|Description||A 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.
|Indication||Measurement 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 Info||Creatinine 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%.
|Interpretation||Creatinine clearance is a measure of the GFR, which has to fall by 50% before a significant rise in serum creatinine is seen.
|Tube||Serum or Heparin|
|Min. Vol||1 mL|
|Ref. Range (Male)||95 - 140|
|Ref. Range (Female)||85 - 125|
|Ref. Range (Paed)|| |
|Ref. Range Notes||
|IP Acute TAT||Refer to Website|
|IP Routine TAT||Refer to Website|
|GP Acute TAT||- Contact Laboratory|
|GP Routine TAT||Refer to Website|
Originally edited by : . Review due on 15/04/2014 14:23:46. Published By Sylvia Bennett on 15/04/2013 14:23:46.