I was told that technically, yes, the reimbursement should go back to the HSA. The money you used to pay for the appointment was pre-tax income. If you spend the reimbursement check like regular money, then it is money that has not been taxed. Technically, it's a no-no.

I've been in the same situation and it's a hassle for me to put money into my HSA. Since the money involved wasn't much, I just pocketed it. And now I can never run for President because I'm a tax cheater.

I don't know about HSA, but for an FSA you definitely have to reimburse the account or submit a receipt for a different (eligible) expense. I would assume that an HSA would be the same, though I don't know how anyone would know unless you are audited.

I used my HSA to pay for an out of network doctors appointment. I then submitted the claim to my insurance company and they send me a check. Do I need to reimburse my HSA or can I pocket the cash?