Volumetric absorptive microsampling (VAMS®) in therapeutic protein quantification by LC-MS/MS: Investigation of anticoagulant impact on assay performance and recommendations for best practices in method development

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

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 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

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.

Multi-Matrix LC-MS/MS Validation of Methotrexate Polyglutamates: Comparison of VAMS, DBS, and Conventional Blood Sampling in Rheumatoid Arthritis — Kocur et al., International journal of molecular sciences · source ↗

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

A validated LC-MS/MS method for everolimus using Mitra and Capitainer devices found excellent agreement between capillary microsamples and venous whole blood in 33 adult transplant recipients. The results showed high accuracy and negligible haematocrit effects, supporting the use of microsampling for decentralised therapeutic drug monitoring.

Therapeutic Drug Monitoring of Everolimus Using Volumetric Absorptive Microsampling and Quantitative Dried Blood Spot Methods with LC-MS/MS in Adult Solid Organ Transplant Recipients: An Analytical and Clinical Comparative Study — Kocur et al., Molecules · source ↗

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