For over 20 years, surveys have identified much inappropriate use of NHS resources. Whether it's attendances at accident and emergency departments, emergency admissions, ambulance call-outs or GP out-of-hours calls, the evidence shows that a significant proportion of these patient contacts are not needed to deal with the problems presented. A major factor behind much of this unnecessary work is the lack of a single 'point' from which the public can obtain information about the best way to handle healthcare concerns.

A basic tenet of a primary care-led NHS is that patients' problems are dealt with in a setting as close to home as possible by the most appropriate means. More care occurs in the home, while GP premises have become a focus for a new range of activities, including minor surgery and rehabilitation. The role of non-medical professionals is steadily expanding, and it is now accepted that nurses have a major role to play in health promotion and managing chronic disease.

One of the most interesting and potentially valuable innovations is the development of the nurse's role in triaging unselected patients. This practice is now well established in A&E, where patients are sorted by clinical priority. And in The New NHS white paper, the government announced a plan to set up NHS Direct, a 24-hour telephone advice line staffed by nurses. Three pilot helplines will begin in March, with the intention of covering the whole country by 2000.

Triage by nurses is already becoming a major component of GP co-operative out-of-hours services, and decisions here may involve whether or not assistance other than home-care advice is required at all. For telephone triage to be cost-effective, not only must patients needing urgent medical care be quickly referred, but those requiring only home-care advice must be identified to reduce unnecessary health service contacts.

In the US, health maintenance organisations have been trying for years to reduce inappropriate resource use. Many have turned to organisations providing telephone triage systems staffed by nurses. About 35 million Americans now have access to telephone triage lines, and in a country where litigation is endemic a market leader, Access Health of Colorado, claims that 25 million calls have been taken since 1986 without a law suit or legal challenge.

Strong evidence suggests that the American public likes telephone triage and that it is clinically safe. But does it reduce use of health services? The American lessons are important for the NHS. Utilisation has only been reduced significantly when nurses have the support of expert software to guide them through the interview with the patient. The leading methodology uses binary branch-chain logic algorithms to take the answer from each question to determine the next question. If only assisted by protocols or guidelines (manual or computerised), nurses tend to err on the side of safety and over-prescribe visits to the doctor or emergency room. GP co-operatives using telephone triage without expert software have found similar results.

If it can be shown that telephone triage by nurses using expert software can work as well in the UK as it does in the US, the possibilities are exciting. It would be feasible to provide for a defined population one telephone number, which could be contacted by anybody with a pressing health problem. During this call, triage would be carried out and appropriate action initiated which could include a GP visit, sending an ambulance, advice about attending a healthcare facility, or home-care advice. This would mean integrating a number of the current rather haphazard arrangements, and would incorporate GP co-operatives, ambulance services and emergency departments.

Telephone triage could be one of those rare innovations from which patients, professionals and managers all benefit. Patients would have just one number to ring for expert advice. Arrangements for those with urgent needs would be quickly made and unnecessary delays in starting treatment avoided. Doctors would see more patients who actually needed their assistance, while triage offers exciting opportunities for nurses to practise their skills. Reducing inappropriate patient contacts should cut costs and gladden hard-pressed managers.

But three major factors have to be overcome: the British expect to contact or call out a doctor when they have a health problem. They are beginning to accept that doctors are not the sole source of health advice, but a major publicity campaign to change attitudes will be needed. Initial experience with nurse triage in GP co-operatives is hopeful, with audit showing high levels of patient satisfaction.

Organisations currently running separate triage systems - and indeed expanding them, as are GP co-operatives and ambulance services piloting the 888 call scheme - will need to change. Health authorities will have a major role in persuading them to share a nurse triage system.

Crucial to success will be the level of investment in the chosen system. Key aspects of the American systems are training and monitoring of nurses, computerised databases and symptom-based algorithms, and a continuous quality improvement system. Nurses must undergo comprehensive initial training, with arrangements for continuing education. The expert software should cover all diagnostic possibilities, and be able to sort patients into categories by level of care required and urgency. Quality improvement should involve external and internal professionals so that systems are regularly reviewed and updated.

The most successful American triage systems not only manage to achieve high satisfaction ratings but do so while exercising the highest levels of utilisation management. With adequate investment, collaboration between NHS agencies, and the support of the public, telephone triage could bring the NHS real benefits.

Dr Alastair Mason is a freelance consultant and a former regional public health director.

'Telephone triage could be one of those rare innovations from which patients, professionals and managers all benefit... Reducing inappropriate patient contacts should cut costs and gladden hard-pressed managers... but a major campaign to change patient attitudes will be needed'