Review of the Preanalytical Errors That Impact Therapeutic Drug Monitoring
Peck Palmer & Dasgupta
The finding, in our words
Preanalytical variables significantly affect therapeutic drug monitoring accuracy, where traditional dried blood spots face challenges with haematocrit bias and filter paper fragility. Volumetric absorptive microsampling provides a fixed-volume alternative that overcomes haematocrit dependency and facilitates self-collection workflows.
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 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.
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.
A review of VAMS and DBS microsampling for TDM of therapeutic monoclonal antibodies, adalimumab, infliximab and others, in inflammatory disease: a convenient, home-friendly alternative to venepuncture that can preserve analytical accuracy, subject to assay-specific validation.