Report of the Advisory Group on Testing for the Presence of Australia (Hepatitis-Associated) Antigen and its Antibody. Contains information on the general principles of testing, methods of testing, training of staff, accommodation and equipment for testing, reagents for testing, Australia antigen or antibody subjects and recommendations. Appendix includes a code of practice for laboratories undertaking such tests, suggested letter to positive donors, suggested letter to gp following agreement by donor and addresses of reference centres in England and wales