Dried plasma spot-based liquid chromatography-tandem mass spectrometry for the quantification of methotrexate in human plasma and its application in therapeutic drug monitoring
Cao et al.
The finding, in our words
The authors validated a dried plasma spot method for methotrexate quantification, showing linearity from 30 to 2000 ng/mL with good precision and accuracy. In 27 patients, concentrations matched wet plasma samples, demonstrating that dried plasma spots can support therapeutic drug monitoring for methotrexate while avoiding haematocrit issues seen with dried blood spots.
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 ↗
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.
VAMS matched serum for the kinase inhibitors nilotinib, cabozantinib, dabrafenib and ruxolitinib, r 0.94–0.97, with serum reliably predictable for the first three, and 93% of at-home samples were collected correctly: at-home VAMS shown feasible for routine cancer-drug monitoring.
Zimmermann et al., J. Pharmaceutical and Biomedical Analysis (paywalled) · source ↗
The authors developed and validated an LC-MS/MS method for measuring three PARP inhibitors in both plasma and dried blood spots. They found strong agreement between the two matrices for olaparib and niraparib, suggesting DBS could support therapeutic drug monitoring for these oncology drugs in decentralised settings.
The study validated an LC-MS/MS method for measuring eight tyrosine kinase inhibitors in dried blood samples collected via VAMS, showing good accuracy, precision and haematocrit independence. It demonstrated agreement with venous sampling, supporting the use of decentralised, patient-centric microsampling for oncology drug monitoring.
Verougstraete & Stove, Journal of pharmaceutical and biomedical analysis (paywalled) · source ↗