Persistent proteinuria is associated with greater frequency of renal morbidity and renal mortality. The purpose of this consensus statement was to describe an appropriate approach for detection, evaluation, monitoring, and treatment of dogs and cats with proteinuria. This disorder has numerous causes, and the statement includes a classification scheme. Assessment involves localizing the origin of proteinuria as well as determining its persistence and magnitude. Step 1 is to rule out extraurinary postrenal causes by evaluating urine collected by cystocentesis. Step 2 is to rule out prerenal causes, such as elevated plasma proteins. Step 3 is to rule in urinary postrenal causes by looking for signs of inflammation or hemorrhage. Step 4 is to rule in pathologic interstitial renal causes by finding inflammation associated with clinical signs of active nephritis. In step 5, the magnitude of proteinuria (urine protein-to-creatinine ratio ≥ 2.0) suggests pathologic, glomerular renal protein loss. Step 6 determines whether proteinuria is mild or transient. Step 7 rules in "pathologic glomerular renal" or "pathologic tubular renal" disease, which are indistinguishable with conventional testing. Recommended responses to persistent proteinuria are also given.

COMMENTARY: Proteinuria in small animal patients is a diagnostic challenge, and emerging evidence indicates that it is important to diagnose, treat, and manage affected patients. In-house diagnostic tests for microalbuminuria have allowed practitioners to identify asymptomatic patients but have also led to confusion about meaningful interpretation of positive results. The ACVIM Consensus Statement gives the latest recommendations concerning this challenging problem and should be read by all.

Assessment and management of proteinuria in dogs and cats: 2004 ACVIM Forum Consensus Statement (Small Animal). Lees GE, Brown SA, Elliott J, et al.J VET INTERN MED 19:377-385, 2005