List of Partners vendors. Liver enzymes are substances produced by the liver that can be measured with a blood test. Any elevation in an enzyme level may be a sign of a liver problem. Aspartate aminotransferase AST and alanine aminotransferase ALT are two of the enzymes doctors look at when trying to figure out if you have a problem with your liver. Aminotransferases are chemicals that the liver uses to make glycogen. Glycogen is the stored form of glucose , the sugar that the body uses for energy.
Any glucose not immediately used will be changed into glycogen. It is then stored in cells for future use. Most will be stored in the liver. The leftover amount will be warehoused in the:. Aspartate aminotransferase AST is found in a variety of tissues, including the liver, brain, pancreas , heart, kidneys , lungs, and skeletal muscles. If any of these tissues are damaged, AST will be released into the bloodstream. While increased AST levels are signs of a tissue injury, it doesn't always relate to the liver.
By contrast, alanine aminotransferase ALT is found mainly in the liver. If your ALT level is high, this may be a sign of a liver injury. It could be minor or severe. Occasional increases in ALT may occur when you have a short-term infection or illness. Sustained increases are more serious. That's because this may mean there's an underlying disease and a greater chance of liver damage. The normal levels vary based on a person's body mass index BMI It also depends on the lab's reference value, or typical results.
Generally speaking, the normal reference value for adults is:. The high end of the reference range is referred to as the upper limit of normal ULN. This number is used to establish how elevated your liver enzymes are. Mild elevations are generally considered to be two to three times the ULN. With some liver diseases, the level can be more than 50 times the ULN.
Levels this high are described as deranged. While it may seem that a high ALT is all that is needed to diagnose liver disease, its relationship to AST can provide valuable clues as to what exactly is going on.
It will also tell you whether the issue is acute occurring suddenly and progressing rapidly or chronic long-standing or persistent. If the liver experiences an acute injury, you can expect to see a sudden spike in the ALT.
On the other hand, if liver disease is slowly progressing, the damage in the liver will gradually affect other organs too. As these organs are damaged, the AST will begin to rise. This occurs with diseases like hepatitis C.
It causes long-term liver damage that triggers symptoms involving:. These are referred to as extra-hepatic symptoms. Depending on which value is elevated and the amount of elevation, doctors can often get a pretty strong indication as to what disease is involved.
Here are the general guidelines used to diagnose liver disease:. However, a disease cannot be diagnosed by the pattern of elevation alone. How elevated the levels are also needs to be measured.
Some foods and drinks can help protect liver health. Learn more about the foods and drinks that are good for liver health here. Hemangiomas of the liver are the most common type of benign liver tumor. Liver hemangiomas rarely cause symptoms, although large or multiple…. Liver metastases occur when cancer spreads to the liver from another part of the body.
Diagnosis may involve ultrasound. Prognosis depends on how far…. Liver cysts are abnormal growths that can develop in the liver. They are uncommon, and most people with liver cysts do not have symptoms. If they…. Liver fibrosis occurs when chronic injury or inflammation causes a buildup of scar tissue. Elevated liver enzymes: Everything you need to know. Medically reviewed by Saurabh Sethi, M. Share on Pinterest If a person has elevated liver enzymes, a doctor may investigate possible underlying causes.
Share on Pinterest A person with hepatitis may experience fatigue, joint pain, and nausea. Testing for elevated liver enzymes. Share on Pinterest Someone with metabolic syndrome may benefit from exercising more, losing weight, and reducing their stress levels. Exposure to air pollutants may amplify risk for depression in healthy individuals. Costs associated with obesity may account for 3. Related Coverage.
What foods protect the liver? Medically reviewed by Kathy W. Warwick, R. What to know about liver hemangiomas. What to know about liver metastases. Elevated enzymes may, however, be useful in motivating behaviour change, with elevated gamma-glutamyltransferase GGT being the best predictor of mortality.
Chronic viral hepatitis may be associated with non-specific symptoms, including fatigue, but most patients are symptom-free. Risk factors for hepatitis include: 3.
Normally suspected following abnormal liver blood tests or an echobright liver on ultrasound scan, non-alcoholic fatty liver disease NAFLD is, in part, a diagnosis of exclusion. When fatty change is seen on ultrasound, other causes including alcohol misuse and viral hepatitis, should be considered.
The BSG guidelines 3 include information on a range of different liver blood tests, providing guidance on how test results should be interpreted and making recommendations for further investigations that may be appropriate. Most laboratories report total bilirubin, which will be raised by an elevation of either the conjugated or the unconjugated form. Interpretation of hyperbilirubinaemia in neonates and infants requires specialist support because of the risk of kernicterus and the need to diagnose with urgency conditions such as biliary atresia.
Albumin is a protein synthesised by the liver that can serve as a marker of synthetic liver function. Albumin concentration may, however, be reduced in other clinical situations, including sepsis, systemic inflammatory disorders, nephrotic syndrome, malabsorption, and gastrointestinal protein loss. Alkaline phosphatase ALP is predominantly a liver enzyme but is also found in bone and in smaller quantities in the intestines, kidneys, and white blood cells.
Levels of ALP are higher in childhood and in pregnancy, where it is associated with bone growth and placental production, respectively. Raised ALP may also result from cholestasis caused by hepatic congestion due to right-sided heart failure. If ALP is elevated in isolation, measurement of GGT see below can help to provide some indication as to whether or not the origin is hepatic, and, if doubt remains, electrophoresis can be used to differentiate hepatic from non-hepatic ALP.
Elevated levels of aspartate aminotransferase AST and alanine aminotransferase ALT are the most common abnormalities seen in liver blood tests. Both AST and ALT are enzymes present in hepatocytes that are released into the blood following hepatocyte injury or death. In contrast, AST is present in cardiac, smooth, and skeletal muscle and may be elevated in myocardial infarction or myositis. In children, creatine kinase measurement may help to determine whether an isolated rise in either of these two enzymes is due to an underlying skeletal muscle disorder, such as muscular dystrophy.
Abundant in the liver and also present in the intestines, kidneys, pancreas, and prostate, but not in bone, GGT can be useful in determining whether elevated ALP is of bone or liver origin. Levels of GGT may be elevated by factors that are not liver-related, including obesity, excess alcohol consumption, and certain drugs.
In spite of this low specificity, GGT is one of the best predictors of mortality in liver disease. As ALP is not a reliable indicator in children, GGT can be used to establish the likelihood of biliary disease, for example congenital abnormalities of the biliary tract and genetic disorders of bile metabolism. Prolonged PT or INR can, therefore, indicate acute or chronic liver dysfunction, but can also be caused by vitamin K deficiency in fat malabsorption and chronic cholestasis.
Platelet reduction is an indicator of advanced liver disease, although platelets may be reduced in a wide variety of medical conditions. In liver morbidity, platelet reduction is associated with splenic enlargement secondary to portal hypertension with consequent platelet sequestration; a reduction in thrombopoietin levels; and reduced platelet production.
When results of liver blood tests are abnormal, the clinical response should include: obtaining a thorough clinical history; performing examinations; and, in appropriate patient groups, considering primary sclerosing cholangitis and viral hepatitis see Box 1 and Figure 1. Guidelines on the management of abnormal liver blood tests. Gut ; 67 1 : 6— Reproduced under the terms of the CC BY 4. This figure details the initial response to abnormal liver blood tests.
Boxes in yellow indicate the initial evaluation of the clinical presentation. For the remainder, a clinical history alongside evaluation ofthe pattern of liver blood test derangement will determine choice of pathway and is shown in the grey boxes.
A grey box indicates all the tests that should be requested at that stage rather than a hierarchy within it. For children, the [guideline] text should be consulted for modification of recommendation.
Areas of diagnostic uncertainty are indicated in orange boxes and the decision for repeat testing or referral to secondary care will be influenced by the magnitude of enzyme elevation and clinical context. Non-alcoholic fatty liver disease is most commonly suggested by an echobright liver on ultrasound and other causes of fatty changes in the liver, including alcohol misuse, must be excluded in order to establish the diagnosis.
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