From the Guidelines
The Creatinine/Albumin ratio, also known as the Albumin-to-Creatinine Ratio (ACR), should be checked in patients with kidney disease, diabetes, or hypertension.
Recommended Testing Frequency
It is recommended to perform the test:
- At diagnosis of kidney disease or diabetes 1
- Annually for patients with normal kidney function and no proteinuria 1
- Every 6 months for patients with stage 1-2 chronic kidney disease (CKD) or those with estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 and/or albuminuria >30 mg/g creatinine 1
- Every 3-6 months for patients with stage 3-4 CKD 1
- Every 1-3 months for patients with stage 5 CKD or those on dialysis
Testing Procedure
The test should be done in the morning, using a first morning void urine sample 1, and the result is considered abnormal if the ratio is greater than 30 mg/g 1.
Importance of Monitoring
It is essential to monitor the ACR regularly to assess kidney function and adjust treatment plans accordingly. Medications such as ACE inhibitors or ARBs may be prescribed to slow kidney disease progression, and their effectiveness can be monitored through regular ACR tests 1.
Special Considerations
In youth with diabetes, urine albumin-to-creatinine ratio should be obtained at the time of diagnosis and annually thereafter, and an elevated ratio should be confirmed on two of three samples 1. In patients with established chronic kidney disease (CKD), monitor urinary albumin (e.g., spot UACR) and eGFR 1–4 times per year depending on the stage of the kidney disease 1.
From the Research
Measuring Creatinine (Creat)/Albumin Ratio
- The Creatinine (Creat)/Albumin ratio, also known as the albumin-to-creatinine ratio (ACR), is a diagnostic marker for chronic kidney disease and can be used to predict the occurrence of nephropathy and cardiovascular disorders in diabetes 2, 3.
- The ACR can be measured in spot urine samples, and its value can be used to screen for albuminuria in cases of prediabetes and diabetes 3.
- The measurement of ACR is recommended for the diagnosis of diabetic kidney disease (DKD) according to various guidelines, and it can be performed either in specialized laboratories or using point-of-care testing (POCT) 2.
Frequency of Measurement
- The frequency of measuring ACR may vary depending on the individual's risk factors and medical conditions, such as diabetes, hypertension, and chronic kidney disease 4, 5.
- For individuals with diabetes, the ACR should be measured at least once a year, and more frequently if they have a history of kidney disease or are at high risk of developing kidney disease 2.
- For individuals with prediabetes, the ACR can be measured as part of a regular health checkup to screen for albuminuria and predict the risk of developing diabetes and kidney disease 3.
Special Considerations
- The ACR measurement can be affected by various factors, such as sex, age, and the presence of comorbidities, and these factors should be taken into account when interpreting the results 5, 6.
- The ACR measurement can be used to monitor protein excretion in patients with chronic kidney disease, and it can be used as an alternative to 24-hour urine measurements 4.
- An elevated ACR, even within the normal range, can be associated with an increased risk of all-cause and cardiovascular mortality, and it can be used as a predictor of cardiovascular risk 5.