The purpose of this study is to investigate the pharmacokinetics of rectal and sublingual administration of tacrolimus and to compare with pharmacokinetics after oral administration of tacrolimus in renal transplant patients before transplantation.

Inclusion Criteria:

• Patients that will have a kidney transplant patient and will be treated with tacrolimus. As well as hemodialysis patients as well as peritoneal dialysis patients are included.
• Age: 18 - 65 years
• Patient's informed consent

Exclusion Criteria:

• Patients that use drugs that interact with tacrolimus
• Patients that participate in other studies
• Patients that are treated with tacrolimus