Abstract
This conference focuses on exciting new work evaluating molecular markers for joint and skeletal diseases. Yet the term “markers” has not been operationally defined. Further, while many studies are now attempting to evaluate the correlation between synovial fluid or serum “markers” and the prevalence or development of such diseases, no one has yet laid out “Koch's postulates” for markers, the criteria that would be necessary to prove the existence of a marker for disease. I shall try both to discuss the different meanings of the word marker when used in the context of a biochemical measure of osteoarthritis and try to develop criteria that might be used to validate whether a potential marker should be accepted definitively.