Does Spare the Dying work on a creature with less than 0HP?

Spare the Dying states:

You touch a living creature that has 0 hit points. The creature becomes stable. This spell has no effect on undead or constructs.

Given the Strict interpretation of RAW it would seem that you would have to have exactly 0hp to benefit from Spare the Dying. Is this correct, or does it stabalize creatures with less than 0hp as well?