As a regional example outside the Bay Area, the UC Davis teaching hospital’s appointment guidance requires full payment at the end of the visit and describes deposits for admitted patients. That hospital’s requirements do not establish the terms at your local practice.
Before a planned referral, request the current estimate, deposit rule and likely timing of further charges from the receiving hospital. Ask what happens if the estimate changes during treatment. Separately, ask the insurer which records and pre-treatment information it can review.
Build a payment plan that works even if a claim takes longer than expected. An insurer’s willingness to review an estimate is not a guarantee that it will reimburse the full final bill.