Your card has a daily transaction limit. This limit is based on a rolling 24-hour period, not a calendar day, and exists to protect your card from unauthorized use.
$5,000 for transactions made at a healthcare provider, like a doctor's office or a hospital
$3,500 for transactions made at a non-healthcare merchant, like a grocery store that offers over-the-counter products
How to pay for an expense greater than the daily limit
You may still spend over the daily spending limit on qualified medical expenses in one day. (Of course, provided you have the needed funds.) Here's how:
Pay up to the daily spending limit for the expense with your debit card, and then either:
Pay the remaining balance the next day with your card.
Immediately pay the remaining balance out-of-pocket and reimburse the expense back to your linked bank account.