Low levels of ALT and AST are commonly found in adult blood tests and are normal for most people. These lower levels are good because they indicate that the liver, heart, pancreas and kidneys are functioning properly and releasing small amounts of the enzymes. It is when the levels start to climb that doctors become concerned about the health of a patient.
When a doctor draws blood to complete an ALT and AST test, they typically look for indicators that something is malfunctioning within the body. Most doctors complete these two tests at the same time because they offer a better ratio for comparison. With these numbers, the doctor can determine the extent of any damage, which allows them to develop a treatment plan. Unlike other enzymes found in the blood, lower levels of ALT and AST are a positive result. If the numbers change between visits, the doctor completes the test over again in a few hours. Since these levels can change drastically within a 6 to 10 hour time span, most physicians need to pay close attention to lab results. For this reason, most doctors choose to run each test multiple times a year for anyone who has a history of infection or illness related to the liver, heart or kidneys.