An ultrasound may be requested by a physician to determine the underlying cause of elevated levels of liver enzymes such as alanine transaminase, or ALT, and aspartate transaminase, or AST, according to American Family Physician. The ultrasound enables a physician to look at the liver and surrounding organs.
The liver may excrete higher-than-normal levels of ALT or AST for different reasons, states Mayo Clinic. Some causes of elevated liver enzyme excretion include hepatitis, gallstones, fatty liver disease, alcohol-related illness, certain types of cancer and gluten intolerance. Some medications, such as acetaminophen, can also cause the liver to excrete more enzymes than usual. When blood tests indicate that these enzymes are higher than ideal, an ultrasound may be performed to assess liver function and to see if the cause of the enzymatic elevation can be determined. Gallstones, tumors or fat deposits on the liver, for example, can be seen on an ultrasound image, allowing a physician to make an accurate diagnosis and initiate treatment protocols.
If the cause of the enzyme elevation is not definitive, a physician may order further testing in order to narrow down the possibilities until a correct diagnosis can be made, states American Family Physician. A physician may order mandatory enzyme level testing at regular intervals if the cause is determined to be medication-related, in order to monitor the health of the patient during treatment.