From the Guidelines
Urine microalbumin should be checked annually in patients with diabetes, starting at diagnosis for type 2 diabetes and after 5 years of disease duration for type 1 diabetes, as recommended by the most recent guidelines 1. This approach is supported by the latest evidence, which emphasizes the importance of early detection and intervention to slow the progression of kidney disease. The preferred screening method is a spot urine albumin-to-creatinine ratio, which corrects for variations in urine concentration, as stated in the guidelines 1. Results between 30-300 mg/g indicate microalbuminuria, while values above 300 mg/g suggest overt proteinuria. Some key points to consider when interpreting the results include:
- Positive results should be confirmed with repeat testing, as transient elevations can occur with fever, exercise, urinary tract infections, heart failure exacerbations, or poorly controlled blood pressure.
- The test detects small amounts of albumin in the urine, which serves as an early marker of kidney damage before more significant proteinuria develops.
- Early detection allows for timely intervention with medications like ACE inhibitors or ARBs to slow progression of kidney disease. It is also important to note that the guidelines recommend annual testing for albuminuria in adults with diabetes using morning spot urine albumin-to-creatinine ratio (uACR) 1. Additionally, if estimated glomerular filtration rate is <60 mL/min/1.73 m2 and/or albuminuria is >30 mg/g creatinine in a spot urine sample, the uACR should be repeated every 6 months to assess change among people with diabetes and hypertension, as recommended by the guidelines 1.
From the Research
Urine Microalbumin Screening
- Urine microalbumin screening is recommended for patients with diabetes, hypertension, and chronic kidney disease 2, 3, 4, 5.
- The screening can be done using a morning spot urine test for albumin-to-creatinine measurement (mg/g) 2.
- Microalbuminuria is defined as a persistent elevation of albumin in the urine of >30 to <300 mg/d (>20 to <200 microg/min) 2.
Frequency of Screening
- The National Kidney Foundation recommends annual screening for microalbuminuria in patients with diabetes or kidney disease 2.
- Patients with hypertension and chronic kidney disease should also be screened annually 3.
- In the first year of treatment, screening should be done every 6 months to monitor the impact of antihypertensive therapy 2.
Importance of Screening
- Microalbuminuria is an established risk marker for the presence of cardiovascular disease and predicts progression of nephropathy 2, 3, 4, 5.
- The presence of microalbuminuria is a marker of endothelial dysfunction and a predictor of increased cardiovascular risk 2, 4.
- Early detection and treatment of microalbuminuria can help reduce the risk of cardiovascular disease and progression of renal disease 2, 3, 4, 5.
Screening Methods
- Microalbumin-specific dipsticks and urinary albumin:creatinine ratio determination (from a spot urine sample) are preferred simple screening methods 3.
- A standard urinary dipstick test can be used to detect microalbuminuria, but it has low sensitivity and should not be used as the sole method of screening 6.