Alpha 1 acid glycoprotein (AGP) is an acute phase plasma protein synthesized by the liver. It functions to regulate the interaction between blood cells and endothelial cells, and together with haptoglobin and C reactive protein, it also mediates the extravasation of cells during infection and inflammation. Expression of AGP is induced by acute-phase stimulatory agents such as bacterial lipopolysaccharides. AGP has a high affinity, low capacity binding for basic drugs at physiological pH. In human plasma, AGP is found at 0.5-1.4 mg/ml. These levels are elevated during acute inflammation; therefore AGP protein levels can be used to diagnose inflammatory conditions. Multiple AGP genes exist, including AGP 1, AGP 2, AGP 3 and AGP 8. AGP 1 and AGP 2 contain five and six potential N-glycosylation sites, respectively. Abnormal expression of the APG 1 gene is linked to sarcoidosis and other immunogenetic diseases, while mutations in the APG 2 gene are associated with different types of carcinomas.