Over-the-Counter Market. 1  Describing a security or trade that does not occur on an exchange. Very often, the OTC market includes securities that are very small and do not trade on an exchange because they do not meet market capitalization requirements. 2  A widespread aggregation of dealers who make markets in many different securities.
Liver tests check the blood for two main liver enzymes: 1  Aspartate aminotransferase (AST), formerly called SGOT; the AST enzyme is also found in muscles and many other tissues besides the liver. 2  Alanine aminotransferase (ALT), formerly called SGPT; ALT is almost exclusively found in the liver.
Gamma-glutamyl transferase (GGT) is an enzyme that is found in many organs, such as the kidney, liver, gallbladder, spleen, and pancreas. Among these, the liver is the main source of GGT in the blood. This test measures the level of GGT in a blood sample.GGT is increased in most diseases that cause damage to the liver or bile ducts. Normally, GGT is present in low levels, but when the liver is injured, the GGT level can rise.GT is usually the first liver enzyme to rise in the blood when any of the bile ducts that carry bile from the liver to the intestines become obstructed, for example, by tumors or stones. This makes it the most sensitive liver enzyme test for detecting bile duct problems.