To provide a service in England and Wales for specialised assays, clinical chemists envisaged a multi-tier system with area, regional, and supraregional laboratories. The Department of Clinical Biochemistry at Addenbrooke's Hospital was established as a regional centre for hormone assays and formal operation started in June 1975. The assays which seemed most suitable for regional development in East Anglia were those for investigating the pituitary-gonad and pituitary-thyroid axes. Most of these were introduced in the first year of operation. A specialised laboratory was not set up: instead, endocrine assays were integrated into a large service laboratory and little expenditure was needed for specialised facilities or staff. The work load of endocrine assays increased markedly during the first year of operation, but the main source of requests was local rather than regional. This lack of use by a region has implications for all three tiers of the specialised service. It suggests that effective centralisation of specialised assays is impracticable unless a dictatorial approach to the problem of rationalisation is made at regional and area level.