Quick Answer. The amount of time it takes for a sound wave to reach the brain is a changing value. The distance of the location from where the sound originates and the type of media the sound travels through are direct factors. Keep Learning.
1 The blood tests most frequently used for liver disease are the aminotransferases (alanine aminotransferase or ALT and aspartate aminotransferase or AST). 2  Normal levels of ALT ranges from about 7-56 units/liter, and 10-40units/liters for AST. Many drugs may cause elevated AST, and ALT and some medications can cause severe damage (for example, acetaminophen [ Tylenol liver damage]). 2  Less common causes of abnormal AST and ALT levels are wide ranging (for example, toxins, and autoimmune diseases).
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test. Alanine aminotransferase (ALT) is present primarily in liver cells. In viral hepatitis and other forms of liver disease associated with hepatic necrosis, serum ALT is elevated even before the clinical signs and symptoms of the disease appear.