Analysis of tamoxifen and its metabolites in dried blood spot and volumetric absorptive microsampling: comparison and clinical application

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.

Clinical Validation of Venetoclax Volumetric Microsampling in Leukemia, with Whole-Blood-to-Plasma Conversion and Self-Microsampling Feasibility — Levens et al., Clinical Pharmacokinetics (paywalled) · source ↗

• vams
• venous-agreement
• blood
• dbs
• tdm
• self-collection
• haematocrit
• dried
• oncology
• capillary
• 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 Blood-Based Microsampling Devices for Patient-Centered Application in Therapeutic Drug Monitoring — Huhn & Scherf-Clavel, Therapeutic drug monitoring (paywalled) · source ↗

• vams
• volumetric
• acceptability
• neoteryx-mitra
• blood
• dbs
• tdm
• self-collection
• haematocrit
• dried
• capillary
• validation

An LC-MS/MS method for tamoxifen and six metabolites in VAMS was developed and validated, with water prerinsing improving recoveries and poor room temperature stability but stability for at least 100 days at minus 80 degrees Celsius. Plasma to blood ratios were used to estimate plasma equivalent concentrations, and paired VAMS and plasma samples from ten breast cancer patients showed strong correlations and good agreement on Bland-Altman analysis, supporting reliable decentralised TDM.

Development and validation of an LC-MS/MS method for the comprehensive quantification of tamoxifen and its metabolites in volumetric absorptive microsampling: clinical application in breast cancer patients — Kuo et al., Analytical and bioanalytical chemistry (paywalled) · source ↗

• blood
• dried
• vams
• neoteryx-mitra
• validation
• venous-agreement
• tdm
• oncology

The study developed and validated a reliable HPLC-MS method for quantifying multiple tyrosine kinase inhibitors from VAMS microsamples of capillary blood, showing acceptable accuracy, precision, and 28-day stability at -21°C, with results comparable to venous plasma in 194 samples from patients with solid tumours. This enables therapeutic drug monitoring using microsamples in oncology practice.

HPLC-MS Quantification of Multiple Tyrosine Kinase Inhibitors in Patients with Solid Tumors: Method Validation and Clinical Application — Staudinger et al., Pharmaceutics (paywalled) · source ↗

• blood
• dried
• capillary
• vams
• neoteryx-mitra
• validation
• tdm
• oncology

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.

Development and application of an LC-MS/MS method for 8 antiepileptic drugs and 2 metabolites using microsampling techniques (DBS and VAMS) — Cobo-Golpe et al., Journal of analytical toxicology · source ↗

• blood
• dried
• vams
• dbs
• neoteryx-mitra
• validation
• venous-agreement
• tdm
• haematocrit