1. Department of Clinical Chemistry, Pinderfields General Hospital, Wakefield
2. Department of Clinical Biochemistry, Southmead General Hospital, Bristol
3. Department of Medicine, Pinderfields General Hospital, Wakefield
4. Division of Steroid Endocrinology, University of Leeds, Leeds
5. Department of Chemical Pathology, St Mary's Hospital, London
6. University Department of Chemical Pathology and Human Metabolism, Southampton General Hospital, Southampton
7. Department of Chemical Pathology, St Thomas's Hospital, London, UK