Considerable progress has been made in the improvement of clinical assays for the detection of autoantibodies to nuclear and intracellular antigens with the use of available World Health Organization (WHO) and Arthritis Foundation/Centers for Disease Control (AF/CDC) standards. The ultimate goal of standardization is for various clinical laboratory test results to be interchangeable and for an exchange of data to be done with confidence. This report discusses the available standards. In addition, significant technical problems and variations in methodologies for the detection of autoantibodies to intracellular antigens noted during a 4-year study by a European Consensus Study Group are detailed. Currently, there is a need for a future generation of reference preparations and standards that will show specific antibody reactivity on sensitive enzymes and immunoblotting assays. Standardization efforts should be done to characterize specific nuclear and cellular antigen preparations that may be of natural or of recombinant technology origin.