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Albumin

The main protein in blood plasma. Made by the liver, it keeps fluid inside your blood vessels and carries many substances.

AI-verified against cited sources. Awaiting expert reviewAlso called ALB, AlbLOINC 1751-7

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What it is

Albumin is the most common protein in your blood. Your liver makes it. It acts like a sponge that keeps fluid from leaking out of blood vessels, and it carries hormones, vitamins, calcium and many medicines around the body. Albumin stays in the blood for weeks, so the level changes slowly. Because many things affect it, albumin is a broad snapshot rather than a test of one organ.

Why it matters

Albumin is often part of a routine panel because it is influenced by the liver, kidneys, inflammation, hydration and the gut. A low level is common during illness and doesn't point to one cause by itself. It is also not a direct test of nutrition. Large studies link lower albumin to higher risk of heart disease and death, but it isn't clear that low albumin causes these problems. It mostly reflects other illness, so clinicians treat the cause, not the number.

If it’s low

A low albumin is common in people who are ill and doesn't point to a single cause. It can mean the liver is making less, protein is being lost through the kidneys or gut, inflammation has moved albumin out of the blood, or the blood is diluted. It is a useful clue that clinicians follow up with other tests.

Common causes

  • Pregnancy, when a lower level is normal
  • Inflammation or acute illness, including infections, surgery and injury
  • Extra fluid in the body or IV fluids, which dilute the blood
  • Liver disease that reduces how much albumin the liver makes, such as cirrhosis
  • Kidney conditions that leak protein into the urine, such as nephrotic syndrome
  • Protein loss or poor absorption in the gut, as in inflammatory bowel disease or celiac disease
  • Long-term poor nutrition or low protein intake, usually together with illness
  • Severe burns or some thyroid conditions

What can help

  • Work with your clinician to find and treat the underlying cause; raising the number itself is not the goal
  • Ask whether urine protein, kidney and liver tests would help explain it
  • During illness or recovery, eating enough protein and calories supports your body, and a dietitian can tailor this

If it’s high

A high albumin is uncommon. It usually means the blood is more concentrated than usual, for example from dehydration, so the number looks higher even though your body hasn't made more albumin.

Common causes

  • Dehydration, such as not drinking enough, heavy sweating, vomiting or diarrhea
  • Sitting or standing before the draw (results run about 6% higher than when lying down)
  • A tourniquet left on the arm for a long time during the blood draw
  • Some medicines, including steroids, insulin and some hormones
  • Lab method differences (the green-dye method reads slightly higher than the purple-dye method)

What can help

  • Drink fluids normally before a retest, unless your clinician tells you otherwise
  • Mention any vomiting, diarrhea or heavy sweating before the draw, and ask whether to repeat the test

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: 3.5–5 g/dL. Source: Mayo Clinic Laboratories, American Board of Internal Medicine, MedlinePlus, National Library of Medicine, Labcorp.

See Albumin by age and sex, with the U.S. survey numbers where they exist.

If this applies to you

Albumin means a little more for some people. Open the one that fits you.

Had weight-loss surgery

Albumin is the main protein in blood. It can fall when the body runs short of protein, and also with infection or inflammation. BOMSS uses routine liver blood tests partly to watch for low albumin.

Blood tests after weight-loss surgery

Celiac disease or IBD

In IBD, a very low albumin reflects significant inflammation or poor absorption, BSG notes. It often goes with poor nutrition but is not itself a measure of nutrition, and BSG says correcting it depends mainly on treating the inflammation.

Blood tests for celiac disease and IBD

Fatty liver or liver condition

Albumin is made only by the liver, so it is part of the standard liver panel. BSG cautions that many other illnesses lower it too, so albumin alone isn't a reliable measure of how severe liver disease is.

Blood tests for liver health

Taking methotrexate

Albumin is part of the BSR's routine methotrexate checks. An unexplained fall in albumin is one of the results it asks clinics to follow up.

Blood tests on methotrexate

How common is your level?

NHANES describes the US civilian, non-institutionalized population, not a 'healthy' reference group. People with disease, on medication, fasting or not (except fasting-subsample markers), smokers and so on are all included. A percentile says where a value sits among Americans of that sex and age, not whether it is normal.

How Albumin varies with age in the U.S.Shaded: middle 90% and middle 50% of people. Line: the median. g/dL. Point at any age, or focus the chart and use the arrow keys, to read both sexes in words.

Use the left and right arrow keys to read each age. Shift moves five years.

Reference data derived from CDC/NCHS National Health and Nutrition Examination Survey (NHANES), cycles 2015-2016, 2017-March 2020 (pre-pandemic), August 2021-August 2023. Analysis by bloodtesttracker.com; not endorsed by CDC, NCHS or HHS.

Explore Albumin by age and sex: every percentile as a table, with a download.

What can affect your result

  • Age: Labcorp's published limits are lower for older adults (3.8-4.8 g/dL at age 62 versus 4.0-5.0 at age 40, in its sample reports)
  • Sex: Labcorp's range for women aged 13 to 30 is slightly lower than for men
  • Posture: about 6% higher upright than lying down
  • Hydration, IV fluids and fluid overload
  • Inflammation and acute illness
  • Pregnancy, some medicines (including birth control pills) and prolonged fasting
  • Lab method: bromocresol green versus bromocresol purple dye
  • Posture: results run about 6% higher after sitting or standing than after lying down.
  • Dehydration concentrates the blood and raises albumin, while IV fluids or fluid overload dilute it and lower albumin.
  • Acute illness and inflammation lower albumin quickly, even when the liver is working well.
  • Pregnancy lowers albumin. Some medicines (including birth control pills) and 24 to 48 hours without food can also lower it, according to MedlinePlus.
  • Dye method: bromocresol green reads higher than bromocresol purple, especially in people with kidney disease, so a change of lab or method can shift your result.

Slow to change from liver or nutrition causes, since albumin lasts about 2 to 3 weeks in the blood (a half-life of about 17 days). It can fall within days during an acute illness or with IV fluids.

When to talk to a clinician

Talk with a clinician soon if your albumin is below your lab's range, especially with new swelling in your legs, face or belly, foamy urine, yellow skin or eyes, ongoing diarrhea or unexplained weight loss. Get urgent care if swelling comes with shortness of breath, or if you feel confused or very drowsy.

Questions you could ask

  • How does my albumin compare with my earlier results?
  • Could dehydration explain this, and should we recheck it when I am well hydrated?
  • What do you think is behind my low albumin?
  • Would urine protein, kidney or liver tests help explain it?
  • Should we recheck it, and when?

Questions people ask

Does low albumin mean I'm not getting enough protein?

Usually not. Illness, inflammation, fluid shifts and protein loss through the kidneys or gut affect albumin much more than diet does. A low result can still prompt a look at your nutrition, but it isn't a direct test of it.

Can I raise my albumin with protein shakes or by eating more protein?

It depends on why the level is low. Treatments aimed only at raising the number have shown limited benefit, so doctors focus on the underlying cause. Ask your clinician or a dietitian before adding supplements.

How do I convert albumin from g/dL to g/L?

Multiply g/dL by 10. For example, 4.0 g/dL is 40 g/L. To go the other way, divide g/L by 10.

Why is my result flagged at one lab but not another?

Labs use different dye methods and different usual ranges. Labcorp, for example, prints narrower limits that change with age and sex, while Mayo Clinic Laboratories uses 3.5 to 5.0 g/dL for adults. Compare your result with the range printed on your own report.

Show the science and sources

Units

  • 1 g/dL = 1 g/dL
  • 1 g/dL = 10 g/L
  • 1 g/dL = 150.4 µmol/L
  • 1 g/dL = 1000 mg/dL

Open the Albumin unit converter

Is a change real?

Albumin naturally varies about 2.6% from test to test in the same healthy person. Between two results from the same lab, a change of roughly 8% or more is unlikely to be day-to-day noise or lab variation (95% reference change value). Source: Critical appraisal and meta-analysis of biological variation estimates for kidney related analytes (Jonker N et al., EFLM WG-BV).

For clinicians and researchers

Albumin (about 66.5 kDa) is made by hepatocytes at roughly 10.5 g/day (about 150 mg/kg/day). Its total-body turnover time is about 25 days, with a half-time of about 17 days, and it provides 60-75% of plasma oncotic pressure. It is a negative acute-phase reactant: inflammation raises capillary leak, enlarges the distribution volume and shortens half-life, so the concentration falls despite higher fractional synthesis. Outside liver disease, synthesis is usually normal or raised, and low albumin reflects redistribution, dilution, greater loss (nephrotic urine, protein-losing enteropathy) or catabolism. It is no longer considered a reliable marker of malnutrition by itself. Worsening hypoalbuminemia is associated with poorer outcomes in cirrhosis, although albumin was not retained as an independent predictor in MELD. Dye-binding methods dominate: bromocresol green shows a positive bias against bromocresol purple, notably in kidney disease, and immunoassays and electrophoresis (a separate SPEP albumin fraction) are alternatives. Pregnancy lowers albumin, so pregnancy-specific intervals apply. Observational meta-analysis (48 cohorts) links higher albumin to lower cardiovascular and all-cause mortality, with causality unresolved.

LOINC 1751-7 (primary), 61151-7, 61152-5, 54347-0. Specimen: serum-or-plasma.

Sources

  1. Albumin, Serum (test ALBS1), Mayo Clinic Laboratories Extended Catalog, Mayo Clinic Laboratories
  2. Comprehensive Metabolic Panel, Serum (test CMAMA), Mayo Clinic Laboratories Extended Catalog, Mayo Clinic Laboratories
  3. Pediatric Testing Reference Ranges (Albumin, test 001081), Labcorp
  4. Albumin (test 001081), sample patient report, Labcorp
  5. Comp. Metabolic Panel (14) (test 322000), sample patient report, Labcorp
  6. Albumin, Serum or Plasma by Spectrophotometry (test 0020030), ARUP Laboratories
  7. ABIM Laboratory Test Reference Ranges, January 2026, American Board of Internal Medicine (2026)
  8. Albumin blood (serum) test (MedlinePlus Medical Encyclopedia), MedlinePlus, National Library of Medicine
  9. Albumin Blood Test (MedlinePlus Lab Tests), MedlinePlus, National Library of Medicine
  10. Liver enzyme alteration: a guide for clinicians, Canadian Medical Association Journal (2005)
  11. Human serum albumin homeostasis: a new look at the roles of synthesis, catabolism, renal and gastrointestinal excretion, and the clinical value of serum albumin measurements, International Journal of General Medicine (2016)
  12. Hypoalbuminemia: Pathogenesis and Clinical Significance, Journal of Parenteral and Enteral Nutrition (2019)
  13. The clinical significance of hypoalbuminaemia, Clinical Nutrition (2024)
  14. Serum albumin, cardiometabolic and other adverse outcomes: systematic review and meta-analyses of 48 published observational cohort studies involving 1,492,237 participants, Scandinavian Cardiovascular Journal (2020)
  15. Effects of posture on concentrations of serum proteins in healthy adults. Dependence on the molecular size of proteins, Scandinavian Journal of Clinical and Laboratory Investigation (1980)
  16. Navigating the Challenge: Selecting the Optimal Assay for Serum Albumin Measurement, EJIFCC (2025)
  17. LOINC codes for albumin (NLM Clinical Tables search), National Library of Medicine

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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