Urine Albumin-to-Creatinine Ratio
Also written as: uACR, Microalbumin, ACR, Albumin-creatinine ratio
Detects small amounts of the protein albumin in urine, an early marker of kidney stress.
What it measures
The amount of albumin, the main protein in blood, that is passing into the urine, divided by urine creatinine to correct for how dilute the sample is. Healthy kidney filters keep almost all albumin in the blood, so urine albumin is measured in very small amounts.
Why a doctor orders it
The standard screening test for early kidney damage, checked regularly in people with diabetes or high blood pressure. It can flag kidney stress years before other kidney tests change.
What is generally associated with a higher result
Broadly associated with early damage to the kidney's filters, most often linked with diabetes and high blood pressure. Temporary rises are also common after exercise, fever, infections, and dehydration, which is why single readings are usually confirmed on another sample.
What is generally associated with a lower result
Low values reflect kidney filters holding onto protein as expected and are generally not pursued.
Everyday things that move this number
Not every shift in a value reflects disease. These are ordinary factors known to affect this particular measurement:
- Vigorous exercise in the day before the sample
- Fever or a recent illness
- A urinary tract infection
- Menstruation or contamination during collection
- Time of day - first-morning samples tend to read lower
Questions to take to your appointment
- Was this a first-morning sample, and does the timing matter?
- Could recent exercise or a passing illness raise this ratio temporarily?
- How do my blood pressure and blood sugar relate to this result?
Build a printable questionnaire with your own results →
Where to read more
MedlinePlus, from the US National Library of Medicine, publishes patient-facing pages on individual lab tests and is a reliable next stop: medlineplus.gov/lab-tests .
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