2025 · BioMed research international · open access
Capillary Blood Self-Sampling for Therapeutic Drug Monitoring: A Mixed-Methods Usability Study of the True Dose<sup>®</sup> Kit
Crafoord et al.
The finding, in our words
The True Dose kit achieved a high System Usability Scale score of 82.7 and enabled 92% of participants to collect the required capillary blood volume, with a median sampling time of 10.42 minutes, indicating good usability but highlighting the need for clearer instructions and stress management to support reliable decentralised sampling.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
At-home volumetric absorptive microsampling (VAMS) for anti-seizure medicines was feasible and reliable, with strong correlations to clinic VAMS and low bias for lacosamide, lamotrigine and levetiracetam; quantitative dried blood spot (qDBS) was a reliable alternative in the ambulatory setting, though older age reduced sampling quality.
This review found that volumetric microsampling devices, such as Mitra, HemaPEN, HemaXis DB10, and Tasso-M20, overcome haematocrit bias, whilst Telimmune plasma separation cards enable direct plasma collection without centrifugation. These technologies support patient-centric, decentralised sampling, though the authors note that clinical validation remains limited across different drugs and patient populations.
The study found that quantitative dried blood spot sampling provided high clinical agreement for tacrolimus and creatinine monitoring, with patients rating the self-collection devices as user-friendly. These results support the feasibility of decentralised therapeutic drug monitoring for immunosuppressants.
Volumetric microsampling can enable patient-centred therapeutic drug monitoring with high patient preference and acceptable method validation for many drugs, but conversion from capillary to plasma and agreement with venous sampling varies by analyte and requires careful validation.
Home DBS sampling gave testosterone results that agreed well with venous blood in men on intramuscular testosterone undecanoate, but showed falsely high values in those using topical gel, likely from skin contamination. Patients preferred home collection for its convenience, suggesting DBS is viable for decentralised monitoring of injectable testosterone if patients are taught proper technique.