What does the Albumin, Serum test measure?

Why is Albumin, Serum measured?

Albumin is the most clinically informative single CMP analyte for nutritional status and hepatic synthetic function. Hypoalbuminaemia (<3.5 g/dL) indicates: chronic liver disease with impaired synthetic capacity; protein-calorie malnutrition or malabsorption; nephrotic syndrome with urinary protein loss; or protein-losing enteropathy. In chronic inflammatory states, albumin falls as a negative acute phase reactant — hypoalbuminaemia in a hospitalised patient does not necessarily indicate malnutrition; concurrent hs-CRP confirms the inflammatory component. Albumin is required to correctly interpret total calcium (albumin correction formula) and total protein (A:G ratio calculation). In functional medicine, albumin above 4.0 g/dL is the target for adequate hepatic synthetic function, nutritional status, and optimal drug binding.

Reference ranges

Standard reference

3.5–5.0 g/dL (35–50 g/L) # REVIEWER FLAG: Confirm Quest Diagnostics reference range for serum albumin — the lower limit of 3.5 g/dL is consistent across most platforms; confirm Quest's specific values.

Functional medicine optimal

4.0–5.0 g/dL (functional medicine optimal — below 4.0 g/dL even within the reference range may indicate early hepatic, nutritional, or inflammatory compromise in the clinical context of fatigue, oedema, or impaired wound healing). # REVIEWER FLAG: Not standardised as a clinical guideline target below 3.5 g/dL — reviewer to confirm framing.

Units

g/dL, g/L

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.