- Plasma 21-deoxycortisol: comparison of a time-resolved fluoroimmunoassay using a biotinylated tracer with a radioimmunossay using (125)iodine. Fiet, J., Boudi, A., Giton, F., Villette, J.M., Boudou, P., Soliman, H., Morineau, G., Galons, H. J. Steroid Biochem. Mol. Biol. (2000)