2018 · Journal of chromatography. B, Analytical technologies in the biomedical and life sciences · paywalled
Carbamazepine, lamotrigine, levetiracetam and valproic acid in dried blood spots with liquid chromatography tandem mass spectrometry; method development and validation
Linder et al.
The finding, in our words
A dried blood spot LC-MS/MS method was validated for therapeutic monitoring of carbamazepine, lamotrigine, levetiracetam and valproic acid. Concentrations from dried blood spots correlated strongly with plasma (R² 0.92) across venous and capillary samples, enabling home self-collection and reducing clinic visits for children with epilepsy.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
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.
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.
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.
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.