Volumetric absorptive microsampling combined with impact-assisted extraction for hematocrit effect free assays
Youhnovski et al.
The finding, in our words
VAMS devices collect accurate blood volumes regardless of haematocrit level, but conventional ultrasonication extraction showed reduced drug recovery at higher haematocrit. A new bead-based impact-assisted extraction eliminated this bias, achieving quantitative recovery of naproxen and ritonavir across all haematocrit levels tested.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
In lung and renal transplant recipients, VAMS sampling with LC-MS/MS quantification of mycophenolic acid and tacrolimus showed good linearity and accuracy, and with a haematocrit-adjusted conversion formula achieved clinical agreement in most samples; tacrolimus did not require haematocrit correction. The approach is virtually painless and enables richer sampling for more accurate drug exposure estimates, supporting decentralised therapeutic drug monitoring.
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.
The study developed and validated a rapid LC-MS/MS method for quantifying cefazolin in capillary whole blood collected via VAMS, plasma, and plasma ultrafiltrate, showing robust performance across matrices and successful application in a pediatric pilot cohort for therapeutic drug monitoring.
This study demonstrates that a commercial conductive vial electromembrane extraction device can reliably isolate basic pharmaceuticals from whole blood collected on volumetric absorptive microsampling tips, showing superior reproducibility and reduced matrix effects compared to conventional treatment.