Anything below 90 is an emergency. Respond accordingly
people on here are assuming things that may or may not be true- a reading below 90 is not an emergency unless it was diagnosed in doctors office. the finger clamp on type for home use often read low Here are typical readings from an actual reviews on the highest rated home use oximaters sold on Amazon:
Wife’s readings - This meter - 85; hospital meter - 92
My readings - This meter - 90; hospital meter - 97