The shortcut that leads closest to blood altar is in fact 93 agility on OSRS.
There's another way to it, which requires 74 agility, but the run is a bit longer (shorter route, higher requirement.. makes sense). I've not checked if the 2nd shortcut actually works or not, but I'd assume it does. Idk, it doesn't really hurt the game if it's lowered I guess, but you already have a 2nd option, and it was intentionally designed that way.
EDIT: It does wok, I checked
Personally, no support.
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