Clearance (medicine)

Renal clearance refers to the clearance through the kidneys, i.e., the removal of a specific exogenous or endogenous substance from the blood as the specific power of the kidney and returns to the plasma volume, which is released per unit time of the corresponding substance.

For example, for the creatinine clearance:

From the renal clearance of specific tracers, the tubules neither secreted nor reabsorbed be such as creatinine or inulin, on the glomerular filtration rate ( GFR) of the kidneys can be closed. Note, however, that it comes to secretion in creatinine in blood> 0.1 mmol / l, so that the clearance appears incorrectly high.

Moreover, it is the name for the Klärwert, namely

  • The movement of a substance from the blood to other tissue (eg, the iron clearance) or from a tissue into the blood ( Gewebsclearance )
  • For function using samples of test substances known excretion behavior.

Creatinine clearance

Normal range 95-160 ml/min/1, 73 m²

Evidence of a slight GFR falls in the range of 90-50 ml/min/1, 73 m²

Evidence of a clear reduction of the GFR to <50 ml/min/1, 73 m² ( = reduction in GFR of at least 50 %)

Evaluation of progression of chronic renal insufficiency

Serum creatinine normal range <1.2 mg / dl

Cockcroft -Gault formula

The simple version of the Cockcroft -Gault formula helps to estimate the creatinine clearance [ml / min].

  • With the unit KreatininPlasma in mg / dl and weight in kg
  • With the unit KreatininPlasma in mmol / l and weight in kg

In women, the calculated value is multiplied by 0.85 because of the lower muscle percentage.

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