Albumin

What is Albumin?

The most abundant protein in blood, made by the liver; albumin keeps fluid inside blood vessels and carries many substances, so it reflects liver synthesis and nutrition.

Albumin is the most abundant protein in blood and is made by the liver, so a serum albumin level offers a window into the liver's protein-making (synthetic) function as well as overall nutrition. Beyond that role, albumin helps hold fluid inside blood vessels and transports substances such as hormones, calcium, bilirubin, vitamins, and many medicines. Because the liver produces it, low albumin can accompany longer-standing liver disease, but it can also reflect poor nutrition, kidney protein loss, inflammation, or conditions that dilute the blood. Albumin turns over slowly, so it changes gradually and is better at reflecting sustained states than sudden events. Higher values are most often linked to dehydration rather than an excess of the protein itself.

What to know about Albumin

Understanding Albumin means knowing what it reflects, what tends to move it, and the signs that suggest it’s worth a closer look — so you can bring the right questions to your next appointment.

How to read a value in context

A 'normal' albumin means the value falls within the population reference interval the lab uses. Because albumin turns over slowly and responds to nutrition, hydration, and inflammation, it reflects a sustained state rather than a moment-to-moment snapshot. A normal result does not guarantee the liver's full function, and a modestly low value can reflect non-liver factors. It is best interpreted with total protein and the rest of the panel.

Lifestyle factors that influence this marker

• Eat adequate high-quality protein and an overall balanced diet within your clinician's guidance to support healthy protein status
• Stay appropriately hydrated, since dehydration can raise and overhydration can lower measured albumin
• Address digestive or appetite issues with your clinician, as poor nutrient absorption can lower albumin over time
• Talk to your doctor before making significant changes to your diet, exercise, medications, or supplements

Tests often checked alongside this

• Total protein — together with albumin gives the fuller protein picture and allows the A/G ratio
• Globulin — the non-albumin protein fraction, interpreted with albumin
• ALT and AST — assess liver-cell injury that may accompany reduced synthesis
• Total bilirubin — part of the broader assessment of liver function

How this can show up in how you look and feel

• Albumin is a blood measurement and does not itself cause symptoms
• Low albumin can be associated with fluid buildup, such as swelling in the legs or abdomen
• Low albumin is sometimes seen alongside fatigue or signs of poor nutrition
• High albumin is usually associated with dehydration rather than symptoms of its own

What can affect this marker

• Liver protein-making capacity
• Nutrition and protein intake or absorption
• Hydration status
• Inflammation, kidney protein loss, and pregnancy

What to track over time

• Your albumin trend over time rather than a single value
• How albumin and total protein move together
• Hydration and dietary protein intake
• Any swelling or fluid-retention symptoms

What to ask your doctor

• Is my albumin change related to my liver, nutrition, kidneys, or hydration?
• Should albumin be rechecked, and alongside which other tests?
• Do my albumin and total protein together suggest anything specific?
• What dietary or lifestyle steps are appropriate for me?

This glossary entry is for informational purposes only and is not a substitute for professional medical advice. Read our Medical Disclaimer.