2022 · Journal of pharmaceutical and biomedical analysis · paywalled
Determination of clozapine and norclozapine in dried plasma spot and dried blood spot by liquid chromatography-tandem mass spectrometry
Carniel et al.
The finding, in our words
Validated methods for clozapine and norclozapine in dried blood and dried plasma spots showed strong correlation with serum concentrations in 13 schizophrenic patients, with dried plasma spots achieving higher accuracy. The analytes remained stable for 26 days at up to 42 °C, indicating these microsampling approaches could enable decentralised therapeutic drug monitoring with practical advantages.
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.
Levens et al., Clinical Pharmacokinetics (paywalled) · source ↗
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.
Cobo-Golpe et al., Journal of analytical toxicology · source ↗
In matched clinical samples from rheumatoid arthritis, VAMS and DBS showed strong agreement for methotrexate polyglutamates (slopes 0.95-1.07; bias within -4.21% to 0.36%; SRCC ≥ 0.969), with up to 100% of total MTXPG results within ±20% limits; capillary microsampling agreed closely with whole blood but differed from red blood cells, indicating matrix-specific differences that must be accounted for when interpreting against RBC-based reference values.
Kocur et al., International journal of molecular sciences · source ↗
The study found a dried blood spot method for ustekinumab was linear from 3 to 12 mg/L with inter-day accuracy of 90.1 to 106%, enabling reliable capillary blood measurement for remote monitoring; the authors note the single-centre design.
A 2025 review maps 28 microsampling devices, from dried spots and volumetric absorptive tips to upper-arm liquid capillary collectors, and names what a laboratory must control before their results are used: the haematocrit effect in non-volumetric dried samples, interstitial fluid from finger milking, volume, haemolysis and transport stability. Regulators on both sides of the Atlantic ask for the same two things, a device the patient can use safely and a sample fit for the test.