Serum & 24 h urine collection
A calculated creatinine clearance may occasionally be required before particular drugs can be prescribed. These drugs depend on on good kidney function in order that the drugs can be removed from the body.
Creatinine clearance (ml/min) =
Urine creatinine x 24 h urine volume
Plasma creatinine x 24 x 60 min
Another way of measuring the adequacy of renal function, commonly used across the UK is the “estimated glomerular function rate“ (eGFR), calculated from a serum blood sample.
Please see eGFRSpecimen Labelling Procedure