Bioassay for detection of methotrexate in serum

S. de Lathouder, A. H. Gerards, E. R. de Groot, M. G. Valkhof, B. A. C. Dijkmans, L. A. Aarden

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3 Citations (Scopus)


Objective: A bioassay is developed for the measurement of methotrexate (MTX) in serum. Methods: The assay is based on MTX inhibition of the proliferation of hypoxanthine-guanosine phosphoribosyl transferase (HGPRT) negative mouse B-cells (B9.H). HGPRT negative cells cannot use the salvage pathway of nucleotide synthesis to overcome inhibition by MTX. Results: When B9.H cells are cultured with serial dilutions of serum, inhibition of proliferation is a measure of the amount of MTX in the serum. Circulating folates do not interfere with the assay. Conclusion: This simple assay can detect low concentrations of MTX in serum: it is therefore useful for following the pharmacodynamics of functional MTX after low-dose MTX treatment
Original languageEnglish
Pages (from-to)167-173
JournalScandinavian journal of rheumatology
Issue number3
Publication statusPublished - 2004

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