You can use your Health Spending Account to cover expenses that are eligible medical expenses under the Income Tax Act (Canada) and that are not paid (or not paid in full) by any other private or government plan. These include eligible expenses incurred outside your province of residence.
Health Spending Account list of eligible expenses
A Health Spending Account can cover the portion of expenses not covered by a health or dental benefits plan. This includes your deductible, co-insurance (portion not covered if your plan covers less than 100%), or amounts that are over your plan maximums. You can also claim expenses not covered under your spouse's plan.