Objective. To test the reliability of the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index and the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) in the assessment of patients with SLE.

Methods. Ten patients with SLE, representing a spectrum of damage and activity, were included. Each patient was examined by 6 of 10 physicians from 5 countries, representing 10 lupus clinics. The SLICC/ACR Damage Index was used to assess accumulated damage, and the SLEDAI was used to assess disease activity. The order of the patients and physicians was randomized according to a Youden square design.

Results. The SLICC/ACR Damage Index detected differences among patients (P < 0.001). There was no detectable observer difference (P = 0.933), and there was no order effect (P = 0.261). Similar results were obtained with the SLEDAI. There was concordance in the SLICC/ACR Damage Index among observers, despite a wide spectrum of disease activity detected by the SLEDAI.

Conclusion. Physicians from different centers are able to assess patients with SLE in a reproducible way, using the SLEDAI to assess disease activity and the SLICC/ACR Damage Index to assess accumulated damage.