Review of ACR renal criteria in systemic lupus erythematosus.

The American College of Rheumatology renal criteria require re-evaluation to incorporate recent advances in the classification of glomerulonephritidies. Renal biopsy is now common and safely performed by experienced nephrologists in community as well as academic settings. The optimal criterion is renal histopathology findings of an immune complex mediated glomerulonephritis as interpreted by an experienced pathologist employing accepted criteria. Renal biopsies should be analysed by routine histopathology, immunofluorescent and electron microscopy. Rating of activity and chronicity should be noted. Secondary criteria for patients unable to undergo renal biopsy includes a combination of findings. These include proteinuria, hypocomplementemia, elevated anti-dsDNA antibodies and an active urine sediment. Proteinuria is a nonspecific finding and, most importantly, can be associated with a number of comorbidities including diabetes, hypertension and atherosclerotic disease. Persistent proteinuria > 0.5 g per day or a spot protein to creatine ratio of > 0.5 should be accompanied by an additional feature supporting active lupus such as positive serologies (hypocomplementemia and/or elevated anti-dsDNA antibodies) and/or active urinary sediment. Similarly, active urinary sediment should be accompanied by the additional criterion of proteinuria to meet renal criteria. Decline in renal function is not a reliable criterion given the numerous medications, comorbidities and other clinical circumstances which may result in this feature.