title: Radioimmunoassay of methotrexate: use of 75Se-labelled methotrexate.
abstract: 75Se-labelled methotrexate has been used as the radiolabel in a radioimmunoassay for methotrexate and its use compared with that of 3H-methotrexate. The gamma-labelled drug has proved to be extremely reliable and easier to use than 3H-methotrexate. Results obtained with it compare well with those obtained with tritiated drug. There are practical advantages in using a gamma emitter, and it is suggested that the modified radioimmunoassay is invaluable for routine monitoring of methotrexate in patients undergoing chemotherapy with the drug.
mesh_terms: D003429:Cross Reactions; D006801:Humans; D008727:Methotrexate / Q000097:blood*; D011863:Radioimmunoassay / Q000379:methods; D011868:Radioisotopes; D012643:Selenium
chemical_list: D011868:Radioisotopes; D012643:Selenium; D008727:Methotrexate