Your dog has had a routine senior blood test or pre-anesthetic screen and the liver enzymes are high. Your dog has no symptoms of liver disease though. They appear completely healthy.This is a very common situation to find yourself in. But what should your next step be?What are liver enzymes?Changes in different liver enzymes mean different thingsALT and AST are used as a marker of liver damage, although AST is also found in muscle and so can also increase if the muscles are damaged.ALKP/ALP and GGT are markers of o problem with the normal flow of bile, a liver waste product. These are also sensitive to diseases outside the liver + non-harmful causes of elevation, as well as also being released from other tissues or in the presence of steroids.What Causes raised liver enzymes in DogsThere are lots of potential causes of raised liver enzymes and screening blood tests are seldom definitive for the exact cause.Sometimes increased serum liver enzyme activities occur because the patient does have primary liver disease, but very often they are secondary to disease outside of the liver. And to confound results even more, tissues other than the liver also produce these enzymes.The liver plays a major role in the metabolism and excretion of drugs, toxins, and waste products. As a result it is susceptible to injury as a direct result of these or due to diseases in other parts of the body. Common examples include dental disease, hormone abnormalities (such as Cushings disease), intestinal disease, and pancreatic disease.Increased liver enzyme activities can occur from benign processes (e.g. hepatic nodular hyperplasia) which is not uncommon in older dogs.Diseases of the liver itself are also numerous and can include infections, cancers, immune problems, and inflammatory conditions.What to do if your dog’s liver tests are high?The answer really depends on your dog!A mild elevation in liver enzymes can be a sign of many things like dental disease, intestinal disease, general inflammation, as well as liver disease of course. Mild elevation can also be completely normal in an older dog, and this is pretty common. The other blood results may prove a clue, as will your dog's history and physical exam.Options include:Rechecking the blood levels a few weeks later to see if there is any change.Treating any other diseases that are known to be present (such as dental disease)More testing, such as a blood test called a bile acid stimulation, or imaging with ultrasound (or xrays).The liver is a very hard organ to know exactly what is going on and in some cases, when everything points to a problem within the liver itself, a biopsy is needed.Head over to the full show notes and learn more about the member hub