Question: We use an answering service that charges us a fee per call. Is it OK for us to invoice patients when they use this service? AAPC Forum Participant Answer: Be careful trying to pass basic operational costs onto patients, especially in situations where patients are seeking healthcare and money might be a barrier to care. If you send an invoice to a patient after they utilized your answering service — which they may have done unintentionally — then your patient may take their business elsewhere and tell others why they left. Instead, account for such costs as part of doing business, like electricity, rent, and other utilities your practice requires.