Lab Metric
Microalbumin (Urine)
Table of contents
Microalbumin measures small amounts of protein leaking into your urine, one of the earliest detectable signs of kidney stress. The test reports albumin alongside urine creatinine and combines them into a ratio, which corrects for how dilute or concentrated the sample is.
Category | Albumin-creatinine ratio | Units |
|---|---|---|
Normal | Less than 30 | mg/g |
Moderately increased | 30 to 300 | mg/g |
Severely increased | Above 300 | mg/g |
Ranges vary between labs, so compare to the range on your own lab report.
What microalbumin measures
Healthy kidneys filter waste out of your blood while keeping useful proteins in. Albumin is the most abundant protein in blood and is normally too large to pass through the filtering units. When those filters are damaged, small amounts begin to escape into urine.
The amount is far too small to show up on a standard urinalysis dipstick, which is why a dedicated microalbumin test is needed. Because urine concentration varies widely depending on how much you have had to drink, the result is divided by urine creatinine to produce the albumin-creatinine ratio. That ratio is the number clinicians act on.
What high or low levels mean
A result below 30 mg/g is normal and suggests the filtering units are intact.
A result between 30 and 300 mg/g indicates moderately increased albumin excretion, historically called microalbuminuria. This is the early warning window, and it matters because it can appear years before kidney function measurably declines. It is most commonly linked to diabetes and high blood pressure, and it is also an independent marker of cardiovascular risk. Caught here, the trajectory is frequently modifiable through blood sugar control, blood pressure management, and specific medications.
A result above 300 mg/g indicates severely increased excretion and warrants prompt clinical evaluation.
A single elevated result is not conclusive. Intense exercise, fever, infection, and dehydration can all raise albumin temporarily, so an abnormal finding is typically confirmed with a repeat test.
Microalbumin FAQ
Why is creatinine measured in the same test?
Urine concentration swings dramatically with hydration, so a raw albumin number can be misleading. Dividing by creatinine, which your body excretes at a steady rate, normalizes the result so samples are comparable regardless of how dilute the urine is.
My regular urinalysis was normal. Why do I still need this?
A standard dipstick only detects protein once levels are considerably higher. Microalbumin is a far more sensitive test designed to catch leakage well before a routine urinalysis would flag it.
Can one high result be a false alarm?
Yes. Strenuous exercise in the prior 24 hours, fever, a urinary tract infection, and dehydration can all elevate the result temporarily. Clinicians generally confirm with a second sample before drawing conclusions.
Read alongside Creatinine and Estimated glomerular filtration rate for a complete picture of kidney health.
Sources
MedlinePlus Medical Encyclopedia, Microalbuminuria test.
National Kidney Foundation, Albumin-to-Creatinine Ratio (ACR).
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