2020 · Journal of pharmaceutical and biomedical analysis · paywalled
Whole blood and oral fluid microsampling for the monitoring of patients under treatment with antidepressant drugs
Marasca et al.
The finding, in our words
This study validated a method using volumetric absorptive microsampling (VAMS) for therapeutic drug monitoring of antidepressants in whole blood and oral fluid. The method showed good extraction yield (84%), precision (relative standard deviation under 15%), and stability (over 85% after three months), with results agreeing well with conventional sampling. By enabling self-collection at home, VAMS simplifies sampling, improves analyte stability, and reduces costs, making decentralised monitoring of antidepressant treatment feasible.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
In AML and CLL, 91% of VAMS venetoclax results fell within 20% of plasma after individualised haematocrit correction; in home sampling, 18 of 21 patients self-sampled independently and 76% of returned samples were analysable, which shows home microsampling is workable, though the authors ask for multicentre validation.
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.
A UPLC-MS/MS method for linezolid and metabolites in oral fluid and VAMS capillary blood satisfied ICH M10 validation requirements. Linezolid concentrations correlated strongly with venous plasma in both matrices, offering a non‑invasive option for therapeutic drug monitoring, whereas metabolites were systematically underestimated in VAMS and seldom detectable in oral fluid, restricting metabolite measurement.
A systematic review found mixed economic evidence for microsampling in therapeutic drug monitoring; one study reported no cost reduction with DBS home-sampling, €688 versus €676, whilst another predicted savings up to 61%. The authors caution that more work is required to assess costs alongside clinical outcomes and optimise logistics for decentralised implementation.
A review of 39 studies found that dried blood spot and volumetric absorptive microsampling show promising results for therapeutic drug monitoring of oral targeted anticancer drugs. The authors state that external validation remains crucial to confirm reliability, citing haematocrit effects and sample stability as key challenges.