Albumin optimal range and reference range

Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026

Sera's bands for Albumin:

Optimal 4 – 5 g/dL (40 – 50 g/L); sufficient 3.5 – 5.5 g/dL (35 – 55 g/L); out of range below 3.5 or above 5.5 g/dL.

Evidence grade: Published reference interval. A band that primarily reflects a published adult laboratory or population reference interval. It is not necessarily applicable to every assay or laboratory.

All units

Unit	Optimal	Sufficient	Out of range
g/dL	4 – 5	3.5 – 5.5	below 3.5 or above 5.5
g/L	40 – 50	35 – 55	below 35 or above 55

What the evidence says

The acceptable band of 3.5 to 5.5 g/dL (35 to 55 g/L) is a standard laboratory interval (Labcorp; MedlinePlus gives 3.4 to 5.4). UK laboratories use the harmonised 35 to 50 g/L, so a UK report will flag above 50 where Sera does not. The optimal band's upper edge of 5.0 g/dL is that UK upper limit. Its lower edge of 4.0 g/dL is a functional target with no specific published threshold: in a US cohort of 31,274 adults, mortality rose step by step below 4.6 g/dL, which supports preferring the upper part of the range rather than any single cut-off. Albumin falls with inflammation, liver disease and protein loss, and rises with dehydration. Albumin reported from protein electrophoresis reads lower than the routine dye-binding method and should not be compared with these bands.

Sources

Hepatic Function Panel (7) (test 322755) sample report — Labcorp, 2016 · Laboratory / reference-interval sourceLabcorp's sample report prints serum albumin 3.5 to 5.5 g/dL, the same as Sera's sufficient band. Report dated 2016; the interval may have been revised since.
Albumin blood (serum) test — MedlinePlus Medical Encyclopedia, US National Library of Medicine, 2025 · Government / public-health guidanceNormal albumin is 3.4 to 5.4 g/dL (34 to 54 g/L), within 0.1 g/dL of Sera's sufficient band at both ends. Reviewed 2/13/2025.
Albumin — York and Scarborough Teaching Hospitals NHS Foundation Trust, Laboratory Medicine test directory, 2026 · Laboratory / reference-interval sourceUK harmonised adult range 35 to 50 g/L. The lower limit matches Sera's sufficient lower edge and the upper limit matches Sera's optimal upper edge of 50 g/L. The page is undated; opened October 2026.
Albumin — University Hospitals Birmingham NHS Foundation Trust, Pathology tests database, 2026 · Laboratory / reference-interval sourceAdults 35 to 50 g/L, sourced to the Pathology Harmony recommendations. Confirms the UK lower limit of 35 and upper limit of 50 g/L. Last updated 19 August 2026.
Serum albumin is incrementally associated with increased mortality across varying levels of kidney function — Brown-Tortorici AR, Naderi N, Tang Y, et al. — Nutrition, 2020 · Peer-reviewed publicationIn 31,274 US adults (NHANES 1999 to 2010), mortality rose progressively as albumin fell below 4.6 g/dL. Supports an optimal band in the upper part of the reference range; it does not identify 4.0 g/dL as a threshold.

What Albumin measures

The most common protein in your blood. The liver makes it, and it keeps fluid in balance and carries hormones, vitamins, and medicines around the body.

Low albumin is one of the strongest warning signs for overall mortality and can point to long-term inflammation, liver problems, poor nutrition, or protein loss through the kidneys. Levels below 4.0 g/dL carry higher risk even when still called normal.

Related liver & pancreas health markers

See Albumin in the full list of biomarker ranges

This page is a reference for practitioners, not medical advice. Sera's bands are practitioner targets for structured review, not diagnostic thresholds, and Sera does not diagnose or recommend treatment. Read a result alongside the interval printed by the issuing laboratory and the client's history and symptoms. Range set: Sera Production, version 1.0, last reviewed November 9, 2026.