Therapeutic drug monitoring of levetiracetam - Is dried blood spot sampling suitable?
Linder et al.
The finding, in our words
Capillary dried blood spot concentrations of levetiracetam agreed closely with plasma, with 92.1% within 20% of the mean and no proportional bias, and capillary matched venous dried blood spot with acceptable deviations; samples remained stable during postal transit, enabling at‑home self‑sampling for therapeutic drug monitoring.
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.
Home DBS sampling gave testosterone results that agreed well with venous blood in men on intramuscular testosterone undecanoate, but showed falsely high values in those using topical gel, likely from skin contamination. Patients preferred home collection for its convenience, suggesting DBS is viable for decentralised monitoring of injectable testosterone if patients are taught proper technique.
VAMS microsampling found no significant difference from venous blood for tacrolimus in paediatric patients; samples were stable for 14 days, with average difference between paired at-home samples of 0.12 ± 0.94 ng/mL.
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.
Guardian-collected capillary dried blood spots were feasible for home monitoring of lamotrigine, and for carbamazepine and valproic acid when conversion factors were applied, with only 4 of 190 comparisons risking a conflicting dose decision and negligible risk of patient harm. Levetiracetam DBS showed high variability against plasma and is recommended only for checking nonadherence, not for dose adjustment.