Effects, costs and implementation of monitoring kidney transplant patients' tacrolimus levels with dried blood spot sampling: A randomized controlled hybrid implementation trial

Aims Dried blood spot (DBS) home sampling allows monitoring creatinine levels and tacrolimus trough levels as an alternative for blood sampling in the hospital, which is important in kidney transplant patient follow-up. This study aims to assess whether DBS home sampling results in decreased patient travel burden and lower societal costs. Methods In this single-centre randomized controlled hybrid implementation trial, adult kidney transplant patients were enrolled. The intervention group (n= 25) used DBS home sampling on top of usual care in the first 6 months after transplantation. The control group (n= 23) received usual care only. The primary endpoint was the number of outpatient visits. Other endpoints were costs per patient, patient satisfaction and implementation. Results There was no statistically significant difference in the average number of outpatient visits between the DBS group (11.2, standard deviation: 1.7) and the control group (10.9, standard deviation: 1.4;P= .48). Average costs per visit in the DBS group were not significantly different (euro542, 95% confidence interval euro316-990) compared to the control group (euro533, 95% confidence interval euro278-1093;P= .66). Most patients (n= 19/23, 82.6%) were willing to perform DBS home-sampling if this would reduce the number of hospital visits. Only 55.9% (n= 143/256) of the expected DBS samples were received and 1/5 analysed on time (n= 52/256). Conclusion Adult kidney transplant patients are willing to perform DBS home sampling. However, to decrease patient travel burden and costs in post-transplant care, optimization of the logistical process concerning mailing and analysis of DBS samples is crucial.