In antinuclear antibody testing, the differences reported by the various methods have caused confusion in the interpretation of test results, controversy over acceptable test performance in proficiency surveys, and conflicting claims about the usefulness of the different methods in common clinical practice. This course reviews the analytic capabilities of the various methods, discusses the advantages and limitations of each, and presents a model for optimizing the use of a screening ANA in low and high disease prevalence situations. Celiac disease is relatively common although under-diagnosed, partially due to poor performance of commonly used screening tests. The faculty will address newer screening tests, including anti-tissue transglutaminase and anti-deamidated gliadin, which demonstrate significantly better performance in detecting the presence of the disease. The faculty will discuss and compare the currently available assays.