Blood and lab tests
What Does Albumin Mean on a Blood Test?
Albumin · say it: al-BYOO-minAlso written: ALB, serum albumin, plasma albumin
Short answer
Albumin is the main protein in your blood plasma. It is made by the liver and helps keep fluid inside blood vessels.
What it means
Albumin is the most plentiful protein in the liquid part of blood. The liver makes it. Albumin acts a bit like a sponge that holds water inside the blood vessels, and it carries hormones, calcium, bilirubin and many medicines around the body.
Albumin is part of the liver function panel and the comprehensive metabolic panel (CMP). The lab reports it because it reflects how well the liver has been making proteins over the previous weeks, and because it can drop when protein is being lost, for example through the kidneys, or when someone is unwell or poorly nourished. A high value most often reflects dehydration, because the blood is more concentrated.
Blood albumin is different from urine albumin. Albumin in urine, often reported as microalbumin or an albumin-to-creatinine ratio, is a kidney test. Albumin is also separate from globulin; together the two make up total protein.
Where you may see it
- Liver function tests (LFTs) and comprehensive metabolic panels
- Hospital blood results, often repeated during a stay
- Calculated lines on a report such as "adjusted calcium" or "A/G ratio"
📄 How it looks on a report
Albumin 31 g/L L
🙅 What it does not mean
- A low albumin does not prove liver disease. Inflammation, recent illness, kidney protein loss, poor appetite and even lying down during the blood draw can lower it.
- Blood albumin is not a measure of how much protein you eat. Diet can play a part, but the level depends mostly on the liver, the kidneys and your overall health.
- It is not the same test as urine albumin or microalbumin, which look for protein leaking through the kidneys.
🗒️ Questions to ask your doctor
🧾 Reports where you will see “Albumin”
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🔗 Read more from trusted sources
- “Albumin” on MedlinePlus ↗
US National Library of Medicine
- MedlinePlus lab test guides ↗
US National Library of Medicine
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General information about a medical word, not advice about your own results. Ask the clinician who ordered the test what it means for you.