A Rapid Enzymatic Assay for Methotrexate in Serum

Summary: A kinetic enzymolqgical assay for methotrexate in serum is described; the results are available after 1.5 hours. The lower limit of sensivity is 50 nmol/1; the day-to-day variation coefficients compare favourably with other procedures (about 1 % in the 200-600 nmol/1 range). The method uses purified dihydrofolic acid reductase from bovine liver. The problem of its instability in the assay is circumvented by several measures, e.g. the use of a reaction rate analyser. Schnelle enzymatische Bestimmung von Methotrexat im Serum Zusammenfassung: Es wird eine kinetische Bestimmung von Methotrexat im Serum beschrieben, deren Ergebnisse i