Recommendations for Reporting Low and High Values for Urine Albumin and Total Protein.

Abstract

To the Editor: Urine albumin (UA)1 and urine total protein (UP) are important biomarkers for assessing, monitoring, and determining treatment and prognosis for people with chronic kidney disease. The Laboratory Working Group of the National Kidney Disease Education Program recommended reporting UA to creatinine ratio (ACR) from a random urine collection, preferably a first morning void, because this value compares well with a 24-h UA excretion rate (1). The Kidney Disease Improving Global Outcomes 2012 recommendations also include reporting the ACR and the protein to creatinine ratio (PCR) for whichever test is performed on a first morning or random urine specimen (2). Clinical studies have demonstrated a strong association between prognosis and level of proteinuria (3), as well as change in response to therapy (4). Most national and professional organization guidelines also recommend reporting ACR or PCR when UA or UP is measured. Clarification is needed for reporting when the measured values for UA or UP are below or above the analytical measuring range (AMR) for the measurement procedures used by a laboratory. Because quantification of UA or UP is needed for treating a patient with kidney disease, urine specimens should …