New microfluidic-based sampling procedure for overcoming the hematocrit problem associated with dried blood spot analysis
Leuthold et al.
The finding, in our words
The foundational quantitative-DBS work: a microfluidic layer meters a controlled 5–10 µL onto a standard card in seconds, targeting the haematocrit problem at source.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
Deprez et al. validated LC‑MS/MS methods for four immunosuppressants and creatinine from a single 10 μL quantitative dried blood spot. With biases under 10 % and CVs below 8 %, the approach enables accurate patient‑centric therapeutic drug monitoring from capillary blood at home, mitigating the haematocrit effect through volumetric collection.
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.
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.
The HematoCARD cartridge autonomously collects duplicate 10 microlitre dried blood spot samples from a single finger prick and shows good analytical performance for monitoring adalimumab, with accuracy between 91 and 111 per cent, linearity R squared 0.99 and coefficient of variation at or above 0.94 compared with serum reference and commercial DBS microsampling methods.
The study compared quantitative dried blood spot (qDBS) and volumetric absorptive microsampling (VAMS) devices for measuring ganciclovir levels in capillary blood from pediatric renal transplant recipients. This comparison provides evidence for choosing between microsampling devices in therapeutic drug monitoring, supporting decentralised sampling approaches that reduce patient burden while maintaining analytical accuracy.