The clinical genetics service in Wales is based at the Institute of Medical Genetics at the University of Wales Healthcare trust in Cardiff.

In 1992, an average block contract price was introduced for each family referred to the service. Last year, geneticists at the unit reported on the first five years' experience, which demonstrated that it was an economically feasible method of charging.

The analysis showed that while the majority of conditions incurred below average cost, a small number of key disorders - notably Huntington's chorea, muscular dystrophy and, to a lesser extent, cystic fibrosis - were responsible for pushing up the mean charge.

Consultant clinical geneticist Dr Helen Hughes and her colleagues pointed out that the system of charging an average price per family rather than varying the cost according to the nature of the disease has four key advantages. It recognises the contribution of both medical and non-medical personnel on the genetics team, covers follow-up - including counselling of relatives - protects the service against loss of income owing to non-attendance, and provides a basis for negotiation when new services are proposed to purchasers.

Initially, some HAs had reservations, and the Cardiff team has spent a lot of time re-educating purchasers as staff change. 'We told them that if they wanted to have an individual pricing system for each case we could do it but the administration charges would put the price up,' explains Dr Hughes. 'The fact is that no one can get their head around a better way of doing it, and they don't have the time. So our system is the simplest option.'

At around 400 new family referrals per million population per year, demand for non-cancer genetic testing has remained very similar since the system was set up. But the growing demand for cancer tests has meant that these have to be budgeted separately at present.

'At first, cancer genetics was handled through research but it is now part of our routine service. However, referral is handled differently from other conditions, through a stepwise system. We are keeping it separate so that we don't imbalance the rest of the service,' adds Dr Hughes.