For clinicians

Albumin

Unit
g/L

What is Albumin?

Albumin is the main protein your liver makes. It keeps fluid inside your vessels, ferries substances through your blood and gives a gentle read on your nutrition: like the delivery vans of your bloodstream. A stable value goes together with a well-functioning liver and a good nutritional state.

Clinical frame

Albumin is the most abundant plasma protein, is made exclusively in the liver and has a half-life of about three weeks. It is a negative acute-phase protein: during inflammation the liver, driven by IL-6, shifts its synthesis to CRP and fibrinogen and albumin falls, partly through capillary leakage and faster breakdown [1].

Because of that slow kinetics, a low-normal or falling albumin reflects persistent low-grade inflammation rather than an acute episode. During inflammation albumin is not a valid nutrition marker: the fall follows the inflammatory response, not intake. So interpret it as a combined marker of liver, nutrition and inflammation [3].

In the Copenhagen General Population Study, among 100,000 people without cardiovascular disease, risk rose almost linearly as albumin fell: per 10 g/L lower, about a quarter more myocardial infarction and a third more stroke, largely explained by the inflammatory component [2]. Dehydration, renal loss and the assay distort the value [3].

What moves this value?

Your diet, your fluid balance, a period of inflammation and your liver and kidney function influence the value.

Enough protein from a varied diet and good hydration support a healthy value. Discuss a persistently low value with your doctor.

Developed and reviewed with the Synapse medical advisory board.

References

  1. Mantovani, A. & Garlanda, C. Humoral innate immunity and acute-phase proteins. N Engl J Med 388, 439–452 (2023). doi.org/10.1056/NEJMra2206346
  2. Ronit, A. et al. Plasma albumin and incident cardiovascular disease: results from the CGPS and an updated meta-analysis. Arterioscler Thromb Vasc Biol 40, 473–482 (2020). doi.org/10.1161/ATVBAHA.119.313681
  3. Evans, D. C. et al. The use of visceral proteins as nutrition markers: an ASPEN position paper. Nutr Clin Pract 36, 22–28 (2021). doi.org/10.1002/ncp.10588

The colour zones are personal: they depend on age, sex, risk and history, and appear in the patient's own report.

Insights to discuss with the patient, not a diagnostic instrument.