2026 · International journal of molecular sciences · open access
Multi-Matrix LC-MS/MS Validation of Methotrexate Polyglutamates: Comparison of VAMS, DBS, and Conventional Blood Sampling in Rheumatoid Arthritis
Kocur et al.
The finding, in our words
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.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
In adult kidney transplant patients, fingerprick VAMS and dried blood spot microsampling achieved accurate simultaneous measurement of tacrolimus, mycophenolic acid, and prednisolone compared with venepuncture. The authors noted an overall preference for VAMS over conventional dried blood spots.
Scuderi et al., Therapeutic drug monitoring (paywalled) · source ↗
Clinical validation for tacrolimus and mycophenolic acid monitoring showed that while volumetric absorptive microsampling met analytical criteria after concentration correction, conventional dried blood spots achieved superior adherence to strict clinical criteria, sample quality, and cost efficiency without significant haematocrit bias.
Paniagua-González et al., Journal of pharmaceutical and biomedical analysis (paywalled) · source ↗
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.
A validated offline SPE-LC-MS/MS method using the Mitra microsampling device successfully quantified tacrolimus, cyclosporine A, tryptophan, kynurenine, and creatinine simultaneously. The method met EMA and FDA criteria, showing agreement between capillary and venous sampling, which could facilitate decentralised therapeutic drug monitoring and transplant follow-up through patient self-collection.
Nierychlewski et al., Therapeutic drug monitoring · source ↗
The study validated a VAMS-based LC-MS/MS method for measuring sirolimus levels, showing it was clinically equivalent to the standard whole blood method and suitable for therapeutic drug monitoring in paediatric transplant patients, supporting the use of decentralised microsampling for this purpose.
Kocur et al., Pharmacological reports : PR · source ↗