Empeiria

Albumin

Also known as ALB

protein · no single molecular formula

LOINC 1751-7 code verified serum g/dL

What this substance is

A 585-residue protein. It has a SMILES string in the same sense that a novel has a letter count -- technically true, practically useless. Its identity is a sequence and a fold, so UniProt and PDB carry it instead.

UniProt P02768 · 585 residues · PDB 1AO6, 1BM0, 1E78

3D model · Protein (PDB 1AO6)

Human serum albumin, one chain, as crystallised (PDB 1AO6). It works as a single chain. Experimental structure from the Protein Data Bank, entry 1AO6, shown as its biological assembly (1 chain). Every chain was checked against its UniProt sequence (at least 100.0% identical). Drag to rotate, scroll to zoom.

Reference ranges

Checking your own result against this range needs the running application; this is a static copy. Nothing you type anywhere in Empeiria is ever sent to a server.

This open edition shows a range only where a public-domain or openly licensed source states one, and none does for this marker yet. Compare your result with the range printed on your own lab report.

How it is measured

In practice

A health worker takes a small blood sample from a vein in your arm with a needle. It usually takes less than five minutes. You don't need to do anything special for an albumin test alone. If other tests are done on the same blood, you may be asked not to eat or drink for several hours.

Serum, or EDTA- or heparin-anticoagulated plasma, from venipuncture; a fasting specimen is desirable. Posture matters: ideally the patient sits for at least 15 minutes before collection, because standing raises and lying down lowers serum albumin. Separated serum or plasma should be removed from cells within one hour. Albumin may be lower after 24 to 48 hours without food.

Before the test

  • Tell your provider about all the medicines you take, but do not stop any without talking to your provider first.
  • If other blood tests are ordered with it, fast (no food or drink) for several hours if your provider tells you to.

Where: laboratory

Sources: Albumin Blood Test, MedlinePlus (U.S. National Library of Medicine); NHANES 2017-2018 Laboratory Procedure Manual, Albumin (CDC National Center for Health Statistics) cited · not yet checked by a person

In the lab

enzymatic colorimetric

Bromocresol green (BCG)

A dye that sticks to albumin is added, and the colour change shows how much is present.

Albumin binds the dye to form a coloured complex, and the colour is measured.

  • Read by: Absorbance of the albumin-dye complex
Why labs disagree: Bromocresol green also reacts with some other proteins, notably alpha-2-macroglobulin, so it tends to read higher than bromocresol purple or antibody-based methods. In kidney disease the gap has ranged from about 0.2 to 1 g/dL, often around 0.5 g/dL. The methods are not interchangeable, and which one a lab runs shifts both its results and the cut-offs that should be applied to them.

Sources: Different serum albumin assays influence the prescriptions in children with primary nephrotic syndrome (Sci Rep 2024), PMC open access; Navigating the Challenge: Selecting the Optimal Assay for Serum Albumin Measurement (EJIFCC 2025), PMC open access cited · not yet checked by a person

What it reports on

Associated symptoms

Conditions this marker features in

When low
  • low Liver damage from alcohol · monitoring
    A low albumin points to more advanced disease, once the liver can no longer make enough protein. It is of little help early on.
  • low Low blood calcium · supportive
    Calcium is adjusted for albumin. Low blood protein makes total calcium read low.
Either direction

Ordered as part of

cmp · hepatic