The microalbumin test measures small quantities of albumin protein in the urine. Albumin is normally found in the bloodstream, and its presence in urine indicates the kidneys may not be filtering waste properly. This sensitive screening tool detects the earliest stages of kidney damage. Fasting is generally not required for the microalbumin test itself.
The Purpose of Microalbumin Testing
Medical providers order a microalbumin test to monitor individuals at high risk for kidney disease. This includes people with Type 1 or Type 2 diabetes and those managing high blood pressure (hypertension). These chronic conditions can damage the filtering units within the kidneys over time.
The test measures microalbuminuria, which is the presence of increased albumin leaking into the urine. Healthy kidneys retain albumin, but early damage allows small amounts to pass through. Detecting this leak provides an early warning sign of diabetic nephropathy or other kidney issues. Early detection allows doctors to adjust treatment plans to slow or prevent the progression toward chronic kidney failure.
Sample Collection Procedures
The microalbumin test uses a urine sample collected via two primary methods. The most common is the random or “spot” sample, often used to calculate the Albumin-to-Creatinine Ratio (ACR). The ACR compares albumin to creatinine, a waste product, which accounts for urine concentration. While a random sample can be taken anytime, providers often prefer a first-morning void for more consistent results.
The second method is the timed or 24-hour urine collection, which measures the total albumin excreted over a full day. This requires collecting all urine in a specialized container over 24 hours, often requiring refrigeration. Regardless of the method, you can eat and drink normally beforehand, as food intake does not interfere with the measurement. However, if your doctor orders concurrent blood work, such as a glucose or lipid panel, you may need to fast for those separate tests.
Factors Affecting Test Accuracy
Although fasting is not required, several temporary conditions can cause a falsely elevated result. Strenuous physical activity within 24 to 48 hours of the test can temporarily increase albumin excretion. Acute illnesses, such as a fever, the flu, or an active urinary tract infection (UTI), also lead to a temporary spike in microalbumin levels.
Dehydration and the presence of blood in the urine (hematuria) are other factors that interfere with accuracy. Inform your healthcare provider if you have any of these conditions before submitting your sample. If the initial result is high, the test is repeated two to three times over a three- to six-month period to confirm a persistent issue.