The Albumin/Creatinine Ratio (ACR) is a test used to detect and monitor albuminuria, which refers to the presence of albumin (a protein) in the urine. The test measures the ratio of albumin to creatinine in a single urine sample, providing an estimate of albumin excretion and helping assess kidney function.

Why is it checked?

1. Screening for Kidney Disease

• Detects early signs of kidney damage, especially in individuals at high risk, such as those with diabetes, hypertension, or a family history of kidney disease.

1. Monitoring Chronic Kidney Disease (CKD)

• Tracks the progression of CKD or response to treatment over time.

1. Assessing Cardiovascular Risk

• Albuminuria is a marker of systemic vascular damage and is associated with an increased risk of cardiovascular events.

1. Detecting Glomerular Damage

• Indicates damage to the glomeruli (the kidney’s filtering units), often due to conditions like diabetic nephropathy or glomerulonephritis.

How it works

• Albumin is a protein that should normally be retained in the blood.
• Creatinine is a waste product of muscle metabolism that is excreted consistently in urine.
• By calculating the ratio of albumin to creatinine, the test accounts for variations in urine concentration, providing a standardized measurement.

Normal vs. Abnormal ACR Values

CategoryACR (mg/g)InterpretationNormal<30No significant albuminuria.Microalbuminuria30–300Early kidney damage, often reversible with treatment.Macroalbuminuria>300Significant kidney damage; requires further evaluation.Symptoms Leading to Testing

The ACR test is often ordered for individuals with:

1. Diabetes or Hypertension

• Early detection of diabetic nephropathy or hypertensive kidney disease.

1. Symptoms of Kidney Disease

• Swelling in legs, ankles, or around the eyes.
• Foamy urine (indicating protein presence).
• Fatigue, nausea, or loss of appetite.

1. High Cardiovascular Risk

• To assess risk of heart attack or stroke in certain populations.

Significance

• Low ACR (<30 mg/g): Indicates healthy kidney function.
• Elevated ACR (30–300 mg/g): Suggests early kidney damage; lifestyle changes, blood pressure, and glucose control are crucial.
• Very High ACR (>300 mg/g): Indicates severe kidney damage, potentially progressing to kidney failure if untreated.

Monitoring and Management

• ACR is often repeated regularly in patients with chronic conditions like diabetes.
• If elevated, interventions include:
• Optimizing blood sugar and blood pressure control.
• Prescribing medications such as ACE inhibitors or ARBs to protect the kidneys.
• Lifestyle changes, including dietary adjustments and exercise.

By identifying kidney damage early, the ACR test plays a critical role in preventing complications and slowing disease progression.