Results From a Proficiency Testing Pilot for Immunosuppressant Microsampling Assays
Veenhof et al.
The finding, in our words
Microsampling assays for immunosuppressant monitoring showed three- to fourfold higher imprecision across 14 laboratories than conventional whole-blood analysis, with coefficients of variation of 11.7 to 18.6 percent versus 3.9 to 4.9 percent. In a patient specimen, this analytical scatter produced a different clinical decision, proving that current microsampling practice lacks the standardisation required for safe home-based therapeutic drug monitoring.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
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.
Kocur et al., International journal of molecular sciences · source ↗
Dried saliva collected with the Mitra device correlated strongly with wet saliva but poorly with plasma unbound and total concentrations, indicating it is not a reliable substitute for plasma in routine therapeutic drug monitoring of mycophenolic acid and its glucuronide metabolite. Capillary blood collected via VAMS remains a promising alternative for long term monitoring in paediatric patients.
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 ↗