Toward needle-free lamotrigine monitoring: Proof-of-concept for saliva and dried saliva spot analysis by LC-MS/MS - a short communication

A UPLC-MS/MS method for linezolid and metabolites in oral fluid and VAMS capillary blood satisfied ICH M10 validation requirements. Linezolid concentrations correlated strongly with venous plasma in both matrices, offering a non‑invasive option for therapeutic drug monitoring, whereas metabolites were systematically underestimated in VAMS and seldom detectable in oral fluid, restricting metabolite measurement.

Simultaneous quantification of linezolid and its metabolites (PNU-142300 and PNU-142586) in oral fluid and capillary blood by UPLC-MS/MS: method validation and clinical application using non-invasive sampling techniques — González-Berdullas et al., Journal of translational medicine (paywalled) · source ↗

• blood
• saliva
• dried
• capillary
• vams
• validation
• venous-agreement
• tdm
• antimicrobials
• haematocrit

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

Guidance on capillary-to-plasma conversion: method- and analyte-specific clinical validation with paired capillary–venous samples before reporting plasma-equivalent results.

To Convert or Not to Convert? Official IATDMCT Guideline on Converting Capillary-Blood Microsampling Concentrations to Plasma Concentrations — Boffel et al., Therapeutic Drug Monitoring (paywalled) · source ↗

• venous-agreement
• blood
• tdm
• standards
• dried
• capillary
• validation

In lung and renal transplant recipients, VAMS sampling with LC-MS/MS quantification of mycophenolic acid and tacrolimus showed good linearity and accuracy, and with a haematocrit-adjusted conversion formula achieved clinical agreement in most samples; tacrolimus did not require haematocrit correction. The approach is virtually painless and enables richer sampling for more accurate drug exposure estimates, supporting decentralised therapeutic drug monitoring.

Evaluation of hematocrit-adjusted conversion strategies for mycophenolic acid and tacrolimus monitoring using volumetric absorptive microsampling in lung and renal transplant recipients — Juan et al., Journal of pharmacy & pharmaceutical sciences : a publication of the Canadian Society for Pharmaceutical Sciences, Societe canadienne des sciences pharmaceutiques · source ↗

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

This study found that volumetric absorptive microsampling shows satisfactory agreement with venous plasma for monitoring several antiseizure medications in paediatric patients. However, a blood-to-plasma conversion factor was required to estimate plasma concentrations for clobazam and carbamazepine metabolites due to poor capillary-to-plasma interchangeability.

Volumetric Absorptive Microsampling (VAMS) for Therapeutic Drug Monitoring of Antiseizure Medications (ASMs) in Pediatric Patients — Simeoli et al., Pharmaceuticals (paywalled) · source ↗

• blood
• dried
• vams
• validation
• venous-agreement
• pediatric
• tdm