Elevated Liver Enzymes: What to Know
One indicator of liver health is the level of liver enzymes. Elevated liver enzyme levels can indicate damage or injury to the liver.
Each laboratory will have its own reference ranges for liver enzymes. In general, normal liver enzyme levels are as follows.
|alanine transaminase (ALT)||4–36 international units per liter (IU/L)|
|aspartate transaminase (AST)||5–30 IU/L|
|alkaline phosphatase (ALP)||30–120 IU/L|
|gamma-glutamyl transferase (GGT)||6–50 IU/L|
|lactate dehydrogenase (LDH)||50–150 IU/L|
On their own, elevated LDH levels may not be related to a condition affecting the liver. However, if elevated LDH levels occur alongside other elevated liver enzymes, it may help doctors determine the cause and severity of the liver condition.
Some of these values may vary depending on individual factors such as sex assigned at birth and body weight.
It is typical for babies under 6 months old to have elevated AST levels. These drop to adult levels by the time they reach 6 months of age.
Learn 10 things to know about your liver.
A variety of conditions can cause elevated liver enzyme levels.
Hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome is a complication resulting from high blood pressure during pregnancy. AST and ALT levels in people with the condition may be more than twice the usual levels.
The condition tends to occur in the third trimester, although some cases can occur up to a few days after delivery.
Alcohol consumption is the leading cause of liver disease in the United States. Alcoholic liver disease causes fats to accumulate in the liver.
Early alcohol-related liver disease may be reversible, but later stages of the condition are permanent.
Drug or medication consumption
Drug-induced liver toxicity is a major cause of acute liver failure in the United States. Over 1,000 different medications and herbs may cause liver problems, with acetaminophen being one of the main triggers.
Other medications that can cause liver damage include:
- nonsteroidal anti-inflammatory drugs (NSAIDs)
- anticancer medications
- cardiovascular medications including statins and blood pressure medication
- certain herbs and supplements, such as green tea extract
Several different viruses can cause hepatitis, or inflammation of the liver, resulting in elevated liver enzymes. These viruses invade healthy liver cells and cause damage.
- Hepatitis A is generally transmitted by ingesting food or water that is contaminated with stool from a person with the virus.
- Hepatitis B transmits through contact with blood or body fluids containing the virus.
- Hepatitis C is transmitted through contact with blood from a person who is infected. Many people do not have symptoms and may be unaware that they have this disease.
- Hepatitis D only occurs alongside hepatitis B and spreads through the same methods.
- Hepatitis E, similar to hepatitis A, transmits through contaminated food or water or undercooked meat or shellfish.
Bile flow problems
Blockage of bile flow can cause elevated liver enzymes. Bile flows from the gallbladder to the small intestine to help the body process fats.
The most common cause of the blockage is gallstones.
Several other conditions can cause elevated liver enzymes. These include:
- nonalcoholic fatty liver disease, which is fat buildup in the liver not resulting from alcohol consumption
- Alagille syndrome, which causes a buildup of bile in the liver
- hemochromatosis, where iron builds up in various areas of the body, including the liver
- Wilson disease, which causes copper buildup in the liver and other organs
- autoimmune hepatitis, or liver inflammation resulting from an atypical immune response
- porphyria, which refers to a group of disorders that can cause a chemical buildup in the liver
- endoscopic retrograde cholangiopancreatography, a procedure used to diagnose and treat issues related to the bile ducts
- Budd-Chiari syndrome, which causes veins that drain the liver to narrow or become blocked by blood clots
Some people with elevated liver enzymes may not have symptoms at all. Researchers estimate that about 1–9% of people with elevated liver enzymes are asymptomatic.
Symptoms of acute liver failure resulting from damage may include:
- jaundice, or yellowing of the skin or the whites of the eyes
- dark colored urine
- pain in the right upper abdomen
- abdominal swelling
- fatigue or malaise
- nausea and vomiting
- gray or clay-colored stools
Chronic liver damage may also cause:
- muscle wasting
- bleeding in the stomach or intestines
- breast development in people assigned male at birth
- changes in the brain
To diagnose the cause of elevated liver enzymes, your doctor will take a detailed history and perform a physical exam. They will assess your alcohol use, medication and supplement use, and personal risk factors. They may ask about your travel history, as some infectious diseases are more common in certain areas of the world.
Tell your doctor about your alcohol use and other risk factors. This may help pinpoint the cause of your elevated liver enzymes.
Testing for liver enzyme levels involves using serum, which is the clear liquid component of blood left after spinning the sample tube in a centrifuge.
Different proportions of liver enzyme elevations point toward different causes. For example, elevated AST and ALT levels can indicate liver cell injury. ALP and GGT indications can indicate bile flow irregularities. Your doctor will take these ratios into account.
Treatment of elevated liver enzymes depends on the underlying cause. People without symptoms or identified risk factors may only need repeated testing to track trends in liver enzyme levels. Acute liver failure may require intensive care hospitalization.
Treatments for elevated liver enzymes may include:
- medication changes
- n-acetylcysteine for acetaminophen poisoning
- weight loss for nonalcoholic fatty liver disease
- alcohol cessation
- antiviral therapy
- surgical management of bile duct or gallbladder issues
- liver transplant
The outlook for people with elevated liver enzymes depends on the cause. Some conditions resolve with minor interventions, such as discontinuing alcohol use or certain medications. Other conditions may have lifelong implications.
Liver issues can affect other organ systems as well. Cerebral edema, kidney failure, problems with bleeding and clotting, and dangerously low blood sugar may occur. These conditions can be fatal if not addressed.
Report symptoms of liver problems to your physician as soon as you notice them. Keep all appointments for doctor visits and laboratory testing.
The risk factors for elevated liver enzymes relate to the conditions that cause them. These factors may include:
- alcohol use
- medication use or misuse
- intravenous drug misuse
- travel to developing nations
- sex without a barrier method or multiple sexual partners
- tattoos or piercings done using shared or nonsterile equipment
Not all causes of elevated liver enzymes are preventable, but you can lower your risk in the following ways:
- Avoid overuse or misuse of acetaminophen. Monitor your total acetaminophen intake and keep it below 3,000 milligrams in a 24-hour period.
- Avoid excess alcohol consumption.
- Maintain a moderate weight.
- Lower your risk of contracting viral hepatitis by:
- avoiding sharing needles or other drug paraphernalia
- avoiding sharing razors, toothbrushes, or nail clippers
- getting vaccinated
- using a condom or other barrier method during sex
- wearing disposable gloves when in contact with another person’s blood or body fluids
While elevated liver enzymes can occur without significant underlying conditions, they may be a sign of liver damage. The specific enzyme levels and ratios help physicians pinpoint possible causes.
If you have signs of liver issues, see your doctor right away.