One of the most common sources of disappointment with private health insurance is receiving an unexpected out-of-pocket bill after a hospital admission. Patients who assumed their gold-tier hospital policy would cover everything discover that certain specialists, anaesthetists, or surgical assistants charged above what the fund will pay. The gap between what a doctor charges and what Medicare and your health fund together pay is called the "out-of-pocket" or "gap" cost — and it can be substantial.
When you are admitted to hospital as a private patient, three separate entities may bill you or bill your insurer: the hospital itself, the treating doctor(s), and any additional clinicians (anaesthetist, surgical assistant, pathologist, radiologist). The hospital component is generally well-covered under your hospital policy — the hospital and your fund have agreed contracted rates. The doctor component is where gaps commonly occur.
Medicare sets a fee schedule for every medical service — the Medicare Benefits Schedule (MBS) fee. Medicare pays 75% of the MBS fee for in-hospital services when you have private hospital cover. Your health fund pays at least the remaining 25% of the MBS fee. Together, Medicare and your fund pay 100% of the MBS fee. The gap arises when your doctor charges more than the MBS fee — which most specialists routinely do.
| Scenario | What it means | Your out-of-pocket |
|---|---|---|
| Bulk billing (no gap) | Doctor charges exactly the MBS fee; Medicare + fund cover 100% | $0 |
| Known gap | Doctor and fund have a gap cover arrangement; you are told the out-of-pocket amount in advance | Fixed known amount (capped at $500 per service under most arrangements) |
| No gap cover arrangement | Doctor charges above MBS and has no arrangement with your fund; you pay the full difference | Unlimited — can be $500 to $5,000+ per procedure |
Before any elective procedure, ask every clinician involved — surgeon, anaesthetist, and any assistant surgeon — whether they participate in a gap cover arrangement with your specific health fund. "I participate in gap cover" means different things at different funds. Ask: "Will I have any out-of-pocket costs from your services under my [fund name] policy?" Get the answer in writing if possible. This conversation protects you far better than any policy comparison does.
Most private health funds offer gap cover schemes in which doctors who participate agree to charge no more than a fund-approved amount. Under "no gap" arrangements, the fund covers the full cost above Medicare's 75%. Under "known gap" arrangements, the doctor may still charge above the MBS fee, but agrees to cap the patient's out-of-pocket at a maximum — typically $250–$500 per specialist encounter, varying by fund. These arrangements are voluntary for doctors. Your fund cannot compel a doctor to participate.
Participation rates vary significantly by specialty. GPs and general surgeons have high participation rates. Some specialties — plastic surgery, spinal surgery, cardiac surgery — have lower participation rates, reflecting the complex fee negotiations and higher market rates in these areas. In major capital cities, more specialists participate in gap schemes than in regional areas.
Doctors are required to inform patients of expected out-of-pocket costs before providing services. In practice, for elective procedures, this should happen before admission. However, for emergency admissions, or when additional clinicians are called in mid-procedure, the billing is determined after the fact. An anaesthetist who attends your surgery under an emergency call-out may have no gap cover arrangement with your fund and may charge at their own discretion.
The lack of upfront disclosure is a known systemic problem in the Australian health system. ACCC and private health funds have repeatedly identified it as a source of consumer harm. Several funds now operate pre-admission cost estimator tools that query which clinicians are involved and whether they participate in gap arrangements. These tools are imperfect but provide more certainty than not checking at all.
Surgical prostheses — joint replacements, cardiac devices, cochlear implants — are covered by the Prostheses List, a government-regulated schedule of benefits health funds must pay for listed devices. The benefit was historically set at the same rate as the most expensive comparable device, meaning some cheaper devices generated a windfall for hospitals. Reform of the Prostheses List since 2022 has reduced fund payments and in some cases created new gaps. Check with your surgeon and fund whether any prosthesis involved in your procedure is covered at the full benefit or whether a gap applies.
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