Multi-Matrix LC-MS/MS Validation of Methotrexate Polyglutamates: Comparison of VAMS, DBS, and Conventional Blood Sampling in Rheumatoid Arthritis.

Arkadiusz Kocur, Marek Kajfasz, Aleksandra Mikulska, Paulina Michalczuk, Brygida Kwiatkowska, Tomasz Pawiński

Abstract readComparative Study

In one paragraph

Article in International journal of molecular sciences, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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0citing papers in PubMed

–field-weighted citation impact

1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

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3 · Its place in the literature

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0 citing papers in PubMed.

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4 · The record

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5 · Who and what money

Authors and funding

6 authors.

Arkadiusz KocurDepartment of Drug Chemistry, Pharmaceutical and Biomedical Analysis, Medical University of Warsaw, Żwirki i Wigury 61, 02-091 Warsaw, Poland.ORCID 0000-0002-4833-8532

Marek KajfaszClinic of Early Arthritis, National Geriatrics, Rheumatology and Rehabilitation Institute, Spartańska 1, 02-637 Warsaw, Poland.ORCID 0009-0004-5978-5241

Aleksandra MikulskaDepartment of Drug Chemistry, Pharmaceutical and Biomedical Analysis, Medical University of Warsaw, Żwirki i Wigury 61, 02-091 Warsaw, Poland.

Paulina MichalczukDepartment of Drug Chemistry, Pharmaceutical and Biomedical Analysis, Medical University of Warsaw, Żwirki i Wigury 61, 02-091 Warsaw, Poland.

Brygida KwiatkowskaClinic of Early Arthritis, National Geriatrics, Rheumatology and Rehabilitation Institute, Spartańska 1, 02-637 Warsaw, Poland.

Tomasz PawińskiDepartment of Drug Chemistry, Pharmaceutical and Biomedical Analysis, Medical University of Warsaw, Żwirki i Wigury 61, 02-091 Warsaw, Poland.ORCID 0000-0001-9110-4312

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Methotrexate (MTX) remains the first-choice treatment for rheumatoid arthritis (RA), but individual variability in response and adherence underscores the need for reliable biomarkers of long-term drug exposure. Intracellular methotrexate polyglutamates (MTXPGs), typically measured in red blood cells (RBCs), fulfill this role but require invasive venous sampling. This study aimed to develop and validate a multi-matrix LC-MS/MS method for measuring MTXPGs in capillary blood samples obtained via volumetric absorptive microsampling (VAMS) and dried blood spots (DBS), and to compare these methods with traditional matrices. The method was validated in accordance with ICH M10 guidelines across RBC, whole blood (WB), VAMS, and DBS samples. MTX and MTXPG

Indexed as

Arthritis, RheumatoidBlood Specimen CollectionDried Blood Spot TestingLiquid Chromatography-Mass SpectrometryMethotrexatePolyglutamic AcidTandem Mass SpectrometryChromatography, LiquidDrug MonitoringErythrocytesHumansReproducibility of ResultsMethotrexatemethotrexate polyglutamatePolyglutamic Acidcapillary bloodLC–MS/MSmedication adherencemethotrexate polyglutamatestherapeutic drug monitoringvolumetric absorptive microsampling

Identifiers

PMID42196403

DOI10.3390/ijms27104429

PMCPMC13207903

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.