• Sjögren's syndrome
• consensus report
• classification

Classification criteria are necessary to identify diseases for which no diagnostic or specific tests yet exist. They are especially of value within the systemic rheumatic diseases. Their main purpose is to organise crude data and information into useful information which will improve clinical care, treatment, and follow up. Classification criteria need to be foolproof so that it is unlikely that changes will be needed in the immediate future.

“Classification criteria should not be interdependent”

Furthermore, they should be carefully defined, with variables independent of each other, totally inclusive, mutually exclusive, and clinically relevant. Epidemiological studies show us that the most common disease within the systemic rheumatic diseases is primary Sjögren's syndrome (SS), followed by rheumatoid arthritis. For primary SS, no international or American College of Rheumatology (ACR) classification set of criteria exists and as the time from a patient's first symptom to diagnosis is 7–9 years, it seems obvious that a new set of classification criteria is needed to add to the seven different sets of criteria produced during the past 25 years.¹ A look at articles published in English within this field shows that the European criteria from 1993 or 1996^{2, 3} are the ones most commonly cited, while the Copenhagen criteria⁴ are used in China and, seemingly, the ones most used world wide.