Alpha-1-acid glycoprotein, also known as orosomucoid, is a member of the alpha-globulin family of proteins found in human serum. It binds many basic drugs and some hormones. It modifies platelet adhesive capacity and may have immunoregulatory functions.
Alpha-1-acid glycoprotein is especially useful in monitoring tumor recurrence. Monitoring is also helpful in differentiating acute phase responses from estrogen effects. In addition, it is an excellent protein to assay along with haptoglobin, where levels should rise concurrently. If alpha-1-acid glycoprotein levels elevate while haptoglobin levels remain normal, this suggests an acute phase response with mild to moderate in-vivo hemolysis.
Normal concentrations of human serum alpha-1-acid glycoprotein are 50-140 mg/dl. Increased levels may be due to inflammation, infection, surgical trauma, tumor recurrence (breast, lung, etc.), or corticosteroid therapy. Depressed levels may be due to nephrotic syndrome, pregnancy, estrogen therapy, end-stage liver disease, or genetic predispositions.