Urine albumin-to-creatinine ratio (ACR) or urine protein-to-creatinine ratio (PCR) is a urinary diagnostic test for proteinuria. This is usually obtained as a random sample, but an early morning sample would be most accurate.
Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group (2013). KDIGO 2012 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney Int Suppl. 2013:3:1-150.