Dried Volumetric Microsampling Approaches for the Therapeutic Drug Monitoring of Psychiatric Patients Undergoing Clozapine Treatment
Marasca et al.
The finding, in our words
The study validated dried microsampling methods for clozapine therapeutic drug monitoring using VAMS and microfluidic blood spot devices. With extraction yields around 85% and satisfactory precision, these approaches could support decentralised monitoring of psychiatric patients, improving compliance and safety.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
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 validated an LC-MS/MS method for eight antiepileptic drugs and two metabolites in dried blood spot and VAMS formats, with satisfactory analytical performance and stability, and was the first to include the oxcarbazepine metabolite DHCB. In 80 paired patient samples, microsampling concentrations showed promising correlation with plasma, supporting decentralised therapeutic drug monitoring of antiepileptic treatment.
In matched clinical samples from rheumatoid arthritis, VAMS and DBS showed strong agreement for methotrexate polyglutamates (slopes 0.95-1.07; bias within -4.21% to 0.36%; SRCC ≥ 0.969), with up to 100% of total MTXPG results within ±20% limits; capillary microsampling agreed closely with whole blood but differed from red blood cells, indicating matrix-specific differences that must be accounted for when interpreting against RBC-based reference values.
In adult kidney transplant patients, fingerprick VAMS and dried blood spot microsampling achieved accurate simultaneous measurement of tacrolimus, mycophenolic acid, and prednisolone compared with venepuncture. The authors noted an overall preference for VAMS over conventional dried blood spots.
Clinical validation for tacrolimus and mycophenolic acid monitoring showed that while volumetric absorptive microsampling met analytical criteria after concentration correction, conventional dried blood spots achieved superior adherence to strict clinical criteria, sample quality, and cost efficiency without significant haematocrit bias.