From the Guidelines
A moderately increased albumin (alb) to creatinine (creat) ratio, also known as moderately increased albuminuria, indicates a urine albumin-to-creatinine ratio (uACR) of 30 to 299 mg/g (3 to 29 mg/mmol), which is equivalent to a 24-h albumin excretion rate (AER) of 30 to 299 mg/day and a urine protein-to-creatinine ratio (uPCR) of 150 to 499 mg/g (15 to 49 mg/mmol) 1.
Key Points
- This ratio is a continuous marker for cardiovascular event risk at all levels of kidney function, with the risk starting at values consistently above 30 mg/g.
- Moderately increased albuminuria is rarely seen with short duration of type 1 diabetes or before puberty, and testing can be delayed in these situations.
- The albumin-to-creatinine ratio is used to classify kidney disease, with A2 being the category for moderately increased albuminuria.
Clinical Implications
- Annual albuminuria testing is recommended at the time of diabetes diagnosis for type 2 diabetes, and 5 years after diagnosis for type 1 diabetes.
- The KDIGO heatmap is used to stage kidney disease and assess cardiovascular risk, with both eGFR and albuminuria needed to properly stage the disease 1.
From the Research
Albumin to Creatinine Ratio
A moderately increased albumin (alb) to creatinine (creat) ratio can indicate early kidney dysfunction or damage 2. This ratio is used as a diagnostic marker for chronic kidney disease and can predict cardiovascular disease 3.
Association with Mortality
Studies have shown that a higher albumin-to-creatinine ratio, even within the normal range, is associated with an increased risk of all-cause and cardiovascular mortality 4. This association is larger among women and younger participants.
Variability and Diagnostic Implications
The albumin-to-creatinine ratio can vary significantly within an individual from day to day, which can make it challenging to interpret changes in albuminuria 5. Multiple urine collections may be required to monitor changes over time, but a single collection may be sufficient for diagnosis.
Key Points
- A moderately increased albumin-to-creatinine ratio can indicate early kidney dysfunction or damage 2
- The ratio is associated with an increased risk of all-cause and cardiovascular mortality, even within the normal range 4
- The ratio can vary significantly within an individual from day to day, requiring multiple collections for monitoring 5
- The ratio is not a reliable predictor of incident diabetes in pre-diabetic individuals 6