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).
ALT and AST are liver enzymes that are part of a comprehensive metabolic panel. Increased levels can be found due to some medications, fatty liver, obesity, diabetes, alcohol, hepatitis, bile duct disease, and many other things.