In 1974, John A. H. Forrest et al. prepared a paper on which the Forrest classification named after him is based. It was originally used to describe bleeding from peptic ulcers. Later studies from 2008 by Elmunzer et al. and 2014 by de Groot et al. recognized the prognostic significance of the classification, particularly for the correlation of bleeding in stages Fl a and Fl b and the probability of recurrent bleeding (Götz 2017).
In a modified form, the Forrest classification can also be applied to non-variceal (ulcer) bleeding (Götz 2017).