Albumin (Serum Albumin)

What is albumin?

Albumin is the most abundant protein in the blood plasma, accounting for approximately 60% of total serum protein. It is produced almost exclusively by the liver — a healthy liver synthesises around 10–15 grams of albumin per day. Because of this, serum albumin is one of the most important indicators of the liver's synthetic capacity.

Albumin performs several critical functions in the body. It is the primary protein responsible for maintaining oncotic pressure — the force that keeps fluid within blood vessels rather than leaking into surrounding tissues. When albumin falls significantly, fluid accumulates in the legs (oedema), abdomen (ascites), and lungs. Albumin also serves as the blood's principal carrier protein, transporting hormones (including thyroid hormones and steroid hormones), fatty acids, bilirubin, calcium, and many drugs. Changes in albumin therefore affect how medications behave in the body.

With a circulating half-life of approximately 20 days, albumin is a marker of chronic protein status and liver function over weeks rather than reflecting day-to-day fluctuations. It is a standard component of liver function tests (LFTs) and nutritional screening panels.

Normal albumin range

The normal adult serum albumin range is:

• Normal: 35–50 g/L
• Mild hypoalbuminaemia: 30–34 g/L — warrants clinical assessment
• Significant hypoalbuminaemia: <30 g/L — often associated with fluid retention and increased medication toxicity risk
• Severe hypoalbuminaemia: <20 g/L — indicates serious illness; clinical urgency

What a low albumin may indicate

Low albumin (hypoalbuminaemia) can result from reduced production, increased loss, or increased breakdown. Common causes include:

• Liver disease — cirrhosis, chronic hepatitis, and advanced liver failure reduce albumin synthesis; a falling albumin is a marker of worsening liver function and prognosis
• Malnutrition and poor dietary protein intake — inadequate protein substrate for albumin synthesis; seen in eating disorders, alcoholism, and severe caloric restriction
• Inflammation and acute illness — albumin is a "negative acute-phase protein" that falls rapidly during infection, surgery, trauma, or inflammatory disease, even when nutritional intake is adequate
• Nephrotic syndrome — large amounts of albumin are lost in the urine due to kidney glomerular damage; results in profound hypoalbuminaemia with oedema
• Malabsorption — Crohn's disease, coeliac disease, and other conditions reducing protein absorption from the gut

What a high albumin may indicate

A high albumin is uncommon and rarely represents a primary clinical problem. Possible causes include:

• Dehydration — the most common cause; as plasma volume falls, albumin becomes more concentrated without any change in total albumin mass
• Haemoconcentration — any condition reducing circulating fluid volume (excessive sweating, vomiting, diarrhoea) can produce a relative rise in albumin
• Laboratory artefact — prolonged tourniquet application during blood draw can artificially elevate protein levels
• True hyperalbuminaemia — extremely rare; no common clinical condition is characterised by genuine excess albumin production

Get your albumin tested at The Vesey

Albumin is included in the following panels at The Vesey Private Hospital, Sutton Coldfield:

• Liver Health Panel — albumin, ALT, AST, GGT, bilirubin, ALP, and total protein
• Nutritional Health Panel — albumin alongside vitamins, minerals, and iron studies
• Lifestyle Screen — comprehensive multi-system panel including liver function
• Advanced Health Panels — full metabolic and organ-function assessment

No fasting strictly required, though it is preferable to fast for 4–6 hours before a liver panel for the most accurate results. Results reviewed by a clinician before release.

Frequently asked questions

Further reading: Albumin — Lab Tests Online UK · Independent patient information from the British Society for Clinical Biochemistry.