Dried Blood Spot Sampling for Therapeutic Drug Monitoring of Vancomycin and Creatinine in the Outpatient Parenteral Antimicrobial Therapy Service: A Qualitative Analysis of Facilitators and Barriers

Background: Dried blood spot (DBS) sampling is considered an alternative sampling strategy for therapeutic drug monitoring (TDM) in patients receiving outpatient parenteral antimicrobial treatment (OPAT). This study was conducted to identify the barriers and facilitators of DBS sampling for patients receiving OPAT. Methods: Patients undergoing DBS sampling for TDM of vancomycin in the OPAT setting were qualitatively evaluated. Patients were interviewed using a semistructured interview guide; patient inclusion ceased when data saturation was achieved. The results were transcribed verbatim and analyzed inductively by 2 researchers using thematic analysis. Results: Eight patients were interviewed. Fifteen barriers and 15 facilitators were classified in 4 domains: information, technique, process, and patient. The overall view of DBS sampling was positive. Patients described the added value of DBS sampling for health care in terms of health care personnel and time. Involvement in their own health care was also mentioned as a positive attribute of DBS sampling. Facilitators included training that provided information on warming the hands, DBS properties (simple and quick to perform, easy integration in routine, time and cost saving), and previous experience with the finger prick procedure. A patient's sense of responsibility is crucial for successfully performing DBS. Barriers included insufficient information on the background of DBS sampling, limitation of assays available for DBS sampling, posting and mail delivery, and aversion toward needles. Conclusions: Barriers and facilitators of DBS sampling for TDM were identified in the OPAT setting, providing insight for proper DBS implementation.