New South Wales
Alexander is incorrect.
The app uses the word 'sanity' and that is defined conclusively in the RRG as your stat and it does not change.
RRG - Health & Sanity wrote:
An investigator’s health and sanity are printed on his Investigator card.
-- Health and sanity are fixed values. An investigator’s health and
sanity are not reduced when he suffers Damage or Horror.
If it meant remaining sanity, it would say something like 'remaining sanity', although I can't recall ever having seen that.