Microalbumin Urine Test in California

What this test measures

Albumin is a protein made by the liver and normally held in the bloodstream by the filtering units of the kidneys. When those filters become damaged or stressed, small amounts of albumin can leak into urine before larger proteins do. A microalbumin measurement detects these low levels, which fall below the range of a standard urine protein dipstick. Catching leakage early gives clinicians a chance to monitor kidney function more closely.

This test uses a random urine sample rather than a full 24-hour collection. Because urine concentration varies through the day, the result is often paired with a urine creatinine measurement and reported as an albumin-to-creatinine ratio. The ratio adjusts for how dilute or concentrated the sample happens to be and is generally more consistent than a bare albumin value when a random sample is used.

The test is typically ordered for people being monitored for chronic conditions that affect the kidneys, or who have a family history of kidney problems. It may also form part of a broader kidney function assessment. Results are read alongside blood tests such as creatinine and estimated glomerular filtration rate, and a single elevated value is often confirmed with a repeat sample.