• Sjögren’s syndrome
• consensus report
• classification

I read with great interest the editorial by R Manthorpe published in the June issue of the Annals of the Rheumatic Diseases.¹ The author reviewed the different criteria that have been proposed for the classification of patients with Sjögren’s syndrome (SS) and, in particular, commented on the US-European Consensus Group criteria,² which were reported for the first time in this same issue. As the first author of the paper, I would like to discuss certain points and criticisms which he raised about our criteria set. First of all I would like to discuss briefly the meaning of “classification criteria” and the methods by which the European^3,4 and US-European criteria for SS² were derived.

Classification criteria are not meant to be used for diagnosis. Diagnosis is an often complex process by which a doctor arrives at the suspicion of a specific disease in a given patient, and then must collect enough clinical data to confirm that suspicion. Classification criteria, on the other hand, represent a tool for research and communication, providing uniform criteria for the scientific community to classify patients with the same disease, select patients for clinical-therapeutic trials, and make the data obtained by different researchers in different series of patients comparable. As any experienced rheumatologist knows, it is not uncommon to diagnose a specific rheumatic disease in a patient who does not meet the classification criteria proposed for that disease.

Given these considerations we can argue that:

• Classification criteria can be used for diagnostic purposes only when they have a sensitivity and specificity of 100%

• Because none of the classification criteria for systemic rheumatic diseases reach this level of sensitivity and specificity, it is evident that some patients with a given disease will fail to be classified as having it, and some normal …