The study, which was funded by the Department for Children, Schools and Families, will inform revisions to the 2002 guidance Promoting the Health of Looked After Children, as promised in the Care Matters white paper.
Compiled by the Thomas Coram Research Unit and the National Children's Bureau (NCB), the report highlights differences in the way the guidelines are implemented throughout Britain.
It states: "Because much of the 2002 guidance is open to interpretation, and because it is not statutory on health, it is implemented in different ways and this has resulted in variable practice and provision across the country."
By interviewing professionals in strategic health authorities, primary care trusts (PCTs) and local councils, the report found there were not enough looked-after children's doctors and nurses. It said information sharing and the quality of health assessments was an area of concern.
It added that in some areas, joint working was "hindered by a silo mentality, poor communication, including tensions in sharing information and confidentiality". The recent reorganisation of PCTs, systemic problems in social care systems and joint working with health were also problems.
NCB officer Helen Chambers, an author of the report, said by placing the role of corporate parent on health services, the needs of looked-after children would be better met. She said: "It is important that there is a clear child-focused agenda at the provider and commissioner level, to promote the health and wellbeing of looked-after children."
But John Simmonds, director of policy at the British Association for Adoption and Fostering, said this was not a simple process: "One problem of looked-after children's health is the absence of primary care taking the role that a parent usually plays. The problem of getting systems that are regularly in contact with children to properly monitor their health is difficult."
A DCSF spokesman said any revised guidance would be statutory for health organisations and local councils.
