Galectin-3

Serum or plasma

0.8 mL

0.4 mL (Note: This volume does not allow for repeat testing.)

Red-top tube, gel-barrier tube, or lavender-top (EDTA) tube

For use in conjunction with clinical evaluation as an aid in assessing the prognosis of patients with chronic heart failure. Galectin-3 levels >17.8 ng/mL are present in a proportion of patients with NYHA class II-IV. Such elevated levels are associated with a more progressive form of heart failure resulting in an increased hazard for death or hospitalization.

Levels of galectin-3 in blood may be increased in patients with certain forms of advanced cancer and other conditions associated with organ fibrosis. Galectin-3 results should be interpreted with caution in such patients. Presence of human antimouse antibodies (HAMA) or rheumatoid factor (RF) may interfere with the galectin-3 assay, which could cause falsely elevated results. The galectin-3 assay should not be used in patients with known HAMA or RF. Galectin-3 results should be interpreted with caution in patients with a history of therapeutic use of murine monoclonal antibodies (IgG) or their fragments or in those who have known autoimmune disorders.

Specimens with high levels of γ-globulins (>2.5 g/dL) may cause false elevation in results. Galectin-3 results from patients with diseases associated with hyperglobulinemia, such as multiple myeloma, should be interpreted with caution.

Enzyme immunoassay (EIA)

Galectin-3 is member of the protein family known as galectins. Galectins bind to certain carbohydrates via specific carbohydrate recognition domains (CRDs). Galectin-3 is a 29 to 35 kDa chimera-type galectin − the only member of the galectin family with an extended N-terminal domain constituted of tandem repeats of short amino acid segments (a total of 110-130 amino acids) linked to a single C-terminal CRD of about 130 amino acids.

Galectin-3 interacts with carbohydrates, such as N-acetyllactosamine (LacNac), certain cell surface receptors (such as macrophage CD11b/CD18) and extracellular receptors (such as collagen). Galectins play an important and complex role in intracellular pathways and disease mechanisms. Under certain circumstances, galectin-3 is secreted in the extracellular matrix and galectin-3 can be measured in plasma or serum of healthy individuals. Galectin-3 has been implicated in a variety of biological processes important in heart failure including myofibroblast proliferation, fibrogenesis, tissue repair, cardiac remodeling and inflammation. Experimental data implicate galectin-3 in heart failure development and progression and administration of galectin-3 can induce cardiac fibrosis and reduced ejection fraction in animals. Blockade of galectin-3 prevents organ fibrosis following inflammation and organ damage.

The experimental data are corroborated by several independent clinical studies that indicated that elevated levels of galectin-3 (>17.8 ng/mL) are associated with an increased near-term or long-term risk for hospitalization or death (p<0.05 after adjusting for pertinent covariates). Galectin-3 levels reflect the presence of specific underlying disease processes and are not affected by the degree of decompensation. Hence galectin-3 levels, once elevated, remain generally constant and do not fluctuate with signs and symptoms of heart failure. Although certain medical and device treatments appear to be effective in patients with elevated galectin-3, galectin-3 plasma levels are generally not affected by these treatments.

Galectin-3 and natriuretic peptides are measures of separate and distinct biological processes. Each marker provides independent and complementary information on the status and prognosis of patients with chronic heart failure.