Campaigners are demanding clarity over whether patients using non drug-based NHS services will be able to 'top up' their care.
National clinical director for cancer Mike Richards' review of co-payments allowed patients to pay for drugs that are not funded by the service, as long as private care was given separately from NHS provision.
Charity Age Concern is now calling on the Department of Health to clarify how far its logic may extend to other situations where NHS funds are used to provide care.
Grey areas in current policy include care home residents fearing they will be forced to meet all their bills once they are paid for with continuing care funding.
There are also questions around new policy areas, such as individual budgets for healthcare.
Afraid to ask for funding
Age Concern care finance policy adviser Pauline Thompson said the charity had heard of cases where elderly care home residents had been afraid to apply for NHS continuing care funding because they feared they would be forced to move to cheaper homes.
She said care home residents should be allowed to top up health service payments, but that their rights to NHS funding must also be spelled out clearly.
"With current support for the idea of being able to top up, we can't see how you can say you can top up all these other things and not top up the care home you wish to go to.
"But we'd also wish to make absolutely sure that there were some mechanisms in place to ensure that the NHS did pay the going rate."
King's Fund senior policy adviser Anna Dixon said whether patients would expect to top up individual health budgets was likely to depend on whether the Department of Health's pilot scheme allowed for direct payments - as in social care - or was simply a "nominal budget".
People receiving direct payments under the social care system are currently allowed to top up.
"The suggestion at the moment is that they are not going to go down the route of direct payments, which would suggest that it probably won't be possible," she said.
A DH spokesperson said the revised guidance on top-ups published by the Department of Health at the time of the Richards review and currently out to consultation, which requires private and NHS care delivered in secondary or specialist environments to take place separately, would apply to future individual budget pilots.