Tacrolimus Can Be Reliably Measured With Volumetric Absorptive Capillary Microsampling Throughout the Dose Interval in Renal Transplant Recipients
Vethe et al.
The finding, in our words
Volumetric absorptive capillary microsampling gave reliable tacrolimus measurements throughout the dose interval in renal transplant recipients, with mean biases of -3.1% for mailed samples and -4.2% for direct delivery versus venous blood. Dried microsamples remained stable for one month at ambient temperature, enabling home-based therapeutic drug monitoring with postal shipment.
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.
A study of 12 kidney transplant recipients providing 69 paired samples found that a VAMS-based assay for mycophenolic acid and its metabolite had 90% to 106% accuracy. Converting microsampling results to plasma concentrations met agreement criteria, supporting decentralised monitoring, though the study was small and limited to a single centre.
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.
In children with SLE, VAMS finger-prick capillary blood gave haematocrit-adjusted MPA and MPAG concentrations indistinguishable from plasma, and the AUC from VAMS derived plasma-equivalent concentrations matched plasma AUC with R2 0.97. This supports accurate pharmacokinetically guided dosing of MMF using only three timed capillary microsamples.
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.