Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services now if someone with diabetes or possible diabetes has confusion, marked drowsiness, a seizure, fainting, new trouble speaking or moving, or cannot be woken normally.
Do not give food, drink, or medicine to someone who is not fully alert.
Emergency assessment is also needed for very high glucose accompanied by severe thirst, repeated urination, worsening weakness, vomiting, inability to drink, or signs of major dehydration.
Do not try to manage suspected HHS at home.
Seek same-day medical advice during illness if your glucose remains much higher than your usual range despite following your sick-day plan, you cannot keep fluids down, or you are unsure how to take your diabetes medicines safely.
Contact your usual diabetes team sooner if practical problems are preventing you from following the plan.
Routine follow-up is appropriate after recovery to review diabetes control, medicines, glucose-monitoring supplies, and your sick-day plan.
Every sign above is quoted from the sofidex article on Diabetic hyperglycemic hyperosmolar syndrome. If you are not sure, err upward — it is always reasonable to be checked.