1. A computer implemented method for processing a transaction involving an account for reimbursing qualified medical expenses and/or patient responsible balances (PRBs), comprising the steps of: receiving enrollment data of participants electing to perform payment-card transactions using accounts for reimbursing qualified medical expenses and/or PRBs; assigning a status to the participant from one of a first and second statuses; receiving from a goods or service provider a request to authorize payment of a qualified medical expense and/or PRB against an account associated with a participant in connection with a first sales transaction between the participant and the goods or service provider; in response to the participant's assigned status being of the first status, electronically performing a real-time substantiation of the first sales transaction using a computerized system, authorizing payment of the qualified medical expense and/or PRB against the associated account, and communicating to the goods or service provider authorization of payment of the qualified medical expense and/or PRB against the associated account, wherein the communicating the authorization occurs subsequently to the real-time substantiation; and in response to the participant's assigned status being of the second status, communicating to the goods or service provider authorization of payment of the qualified medical expense and/or PRB against the associated account, effecting the payment of the qualified medical expense and/or PRB against the associated account, and electronically performing a retrospective substantiation of the first sales transaction using a computerized system, wherein the retrospective substantiation is performed subsequently to the communication of the authorization.