Galectin-3
A protein involved in inflammation and scarring (fibrosis), including of the heart muscle. In heart failure, a higher level reflects ongoing fibrosis and remodelling and is linked to a worse outlook, so it is used mainly as a prognostic marker alongside the natriuretic peptides BNP and NT-proBNP.
What it measures
Galectin-3 is a protein that plays a role in inflammation and, importantly, in fibrosis — the formation of stiff scar tissue. In the heart, the processes that galectin-3 reflects contribute to 'cardiac remodelling', where the heart muscle becomes stiffer and less efficient over time. Its main clinical use is in heart failure, where it acts as a marker of this ongoing fibrosis and remodelling rather than of the moment-to-moment strain on the heart (which the natriuretic peptides BNP and NT-proBNP reflect). A higher galectin-3 level in someone with heart failure is associated with a worse prognosis — more disease progression and a higher risk of hospitalisation — and it adds information beyond the natriuretic peptides. It is used for risk stratification and to help gauge outlook, not to diagnose heart failure on its own. Because galectin-3 is involved in fibrosis generally, levels can also be influenced by kidney disease and other fibrotic conditions, so it is interpreted in the clinical context. It is a specialist, prognostic marker rather than a routine test.
What a high value can mean
- Worse prognosis in heart failure — reflects ongoing cardiac fibrosis and remodelling; linked to disease progression and higher risk of hospitalisation.
- Kidney impairment — can raise it, as galectin-3 is cleared by the kidneys and involved in fibrosis generally.
- Other fibrotic or inflammatory conditions — can contribute, so it is read in context.
What a low value can mean
- Lower fibrotic/remodelling activity — a more reassuring prognostic result in heart failure.
- Normal — the expected result outside significant cardiac or fibrotic disease.
When to discuss with a doctor
Galectin-3 is a specialised prognostic marker used mainly within the care of heart failure, not a test to diagnose it or to act on by yourself. In someone with known heart failure, a higher level suggests more active cardiac fibrosis and a higher risk of progression, adding to the information from BNP or NT-proBNP and helping the cardiology team gauge outlook and intensity of management. Because kidney disease and other fibrotic conditions also affect it, it is always interpreted in the full clinical context. Mediora.AI shows galectin-3 alongside the natriuretic peptides and the rest of your cardiac and kidney markers so it is read in context; the prognostic interpretation belongs with your doctor.