- Creatinine clearance >80 ml/minute as measured from a 24 hour urine collection within 26 weeks of the screening visit. If a serum creatinine drawn at the screening visit is > 20% higher than the serum creatinine drawn at the time of the 24 urine collection, the creatinine clearance must be re-evaluated by a repeat 24 hour urine test. If the new value is ≤80mg/dL the donor will be excluded.