Implementing Dried Blood Spot sampling in transplant patient care

Dosing of immunossuppressive drugs used for transplant patients’ allograft rejection prevention is based on blood drug levels. This requires transplant patient to frequently provide a venous blood sample in the hospital. The Dried Blood Spot (DBS) method enables patient home sampling by means of collecting drops of fingerprick blood on a sampling card. This card can be sent to the laboratory by mail. From this DBS sample, blood drug levels can be measured. The purpose of the DBS method is to reduce patient burden and societal costs. In this thesis entitled ‘Implementing Dried Blood Spot sampling in transplant patient care’, a description is given how to successfully implement the DBS method. The analytical method should be fast, robust and meet all criteria of relevant guidelines. In addition, DBS-specific parameters should be validated. The DBS method should be tested in a clinical validation study where DBS results are compared to results from paired venous samples. In practice, providing a DBS sample is not easy. A checklist was developed which enables objective judgment of DBS sample quality. In addition, an app was developed enabling patients to determine the quality of a DBS by means of taking a photo of the sample. We found that the logistics concerning the sending and analysis of DBS samples are very critical to achieve a successful implementation. We also found that a novel home sampling technique involving fingerprick blood sampling on a volumetric tip was inferior to the DBS method regarding both sample quality and interchangeability with venous blood results.