A randomized controlled trial comparing Dried Blood Spot sampling to venous sampling for Therapeutic Drug Monitoring in tacrolimus using kidney transplant patients: a cost minimization analysis.

Immunosuppressants such as Tacrolimus (TaC) are successfully applied in solid
organ transplantation to prevent allograft rejection. Because of their narrow
therapeutic range and significant inter- and intra-individual variability in
absorption and metabolism, therapeutic drug monitoring (TDM) is important in
the clinical follow-up of immunotherapy receiving transplant patients to
balance between subtherapeutic and toxic effects of these drugs. Outpatients
receiving immunotherapy need to travel to the hospital on a regular basis for
follow-up and to have their blood samples taken and analyzed. The results of
the analysis are obtained the next day forcing the physician to call the
patient and discuss dose change. With the use of Dried Blood Spots (DBS),
capillary blood is obtained through a fingerprick with a lancet and is applied
to a sampling card. This method is patient friendly and allows patients to
sample at home and sent the DBS card to the laboratory by mail. This saves
patient transportation costs and time and possibly visits to the policlinic. In
addition, the monitoring results will be timely available for the clinician
before patients visit the clinic for their routine check-up. To date, however,
no studies have investigated the costs and effects of DBS in clinical use.
Providing evidence for the cost-effectiveness of DBS may lead to a more
widespread use of this technology and thus cost savings and an increase of the
quality of care for the transplant patient.

To determine the difference in the amount (average per patient) of clinical
check-ups performed in the hospital for the DBS and the non-DBS group. To
compare the total economic burden for the intervention and non-intervention
groups from a societal perspective using cost-minimization analysis.
To determine the satisfaction of patients using dried blood spots.

prospective, randomized controlled trial.

In the DBS group, patients will undergo training in DBS sampling while they are
still hospitalized. In the week prior to their routine check-ups they will
perform a DBS and sent it to the laboratory of hospital pharmacy of the UMCG
for analysis. The blood drug concentrations will be discussed with the patient
at the check-up in the policlinic. All patients in this group will be treated
according to the standard care. Four weeks after inclusion the patient will
receive a questionnaire in which questions will be asked about the loss in
worktime, feasibility and satisfaction of DBS.

The control group will not receive training in DBS. Blood sampling will take
place in the UMCG by acquiring wholeblood through a venapuncture. The blood
drug concentration will be discussed with the patient by phone or at the next
check-up in the policlinic. All patients in this group will be treated
according to the standard care. Four weeks after inclusion the patient will
receive a questionnaire in which questions will be asked about the loss in
worktime.

Depending on randomization:
- Performing the Dried Blood Spots sampling method at home (DBS-group)
- Use conventional whole blood sampling at the UMCG (control-group)
- Filling in a questionnaire

Patients will receive standard care in either group and will have to undergo
little extra proceedings. From the patients* perspective, only the training in
DBS, the application of a fingerprick instead of venous blood sampling and
filling in a questionnaire will be extra to the received care. There is no risk
associated with either of these proceedings.