The liver is an organ located in the abdominal cavity, in the upper right part just below the rib cage. It may seem insignificant, but the liver happens to be one of the biggest and most important organs in the human body.
Are you concerned about your liver enzyme levels? Do you know what the normal range is for your age and gender? If not, you're not alone. Most people don't know about their liver enzyme levels until they are diagnosed with a problem. But it's important to know where your numbers stand so that you can take steps to improve your well-being if needed.
To help, we've put together this liver enzymes levels chart. It shows the normal range for adults of both genders and the high and low end of each spectrum.
Liver enzymes
Enzymes are body proteins that are present to speed up chemical reactions in the body. In the liver, there are also enzymes responsible for performing this function in the body - the two most common liver enzymes are ALT (Alanine aminotransferase) and AST (aspartate aminotransferase).
If the liver develops a disease or starts to get damaged, these enzymes find their way into the bloodstream and will be seen when a liver blood test is carried out. This inadvertently means that higher ALT and AST values than normal, in the blood signify liver damage.
Low liver enzyme levels, on the liver enzyme levels chart, signify that your liver is healthy, although sometimes a patient may have low liver enzyme levels and still have a damaged liver.
Aminotransferase Enzymes, What are They?
Aminotransferase enzymes are liver enzymes that catalyze chemical reactions. The chemical reactions involve transferring an amino group to a recipient molecule from the donor molecule. This is where the name “aminotransferase” comes from.
Two aminotransferase enzymes are ALT and AST - Alanine Aminotransferase and Aspartate Aminotransferase.
Aspartate Aminotransferase is found usually in tissues including the kidney, brain, muscle, heart, and of course, the liver. When there is a tissue damage, the enzymes get released right into the serum.
The AST, for example, gets released into the serum when you have a muscle injury or during a heart attack causing elevated enzyme levels. This means that elevated AST levels may not always be an accurate indicator of liver damage.
ALT, on the other hand, is found usually in the liver, even though not exclusively. During a liver injury, it gets released into the serum, indicating that there has been a liver injury or damage.
Liver Enzymes Level Chart
The liver enzymes levels chart reveals what enzyme levels are normal, and what levels are elevated. This is usually checked with a liver test:
- ALT enzyme’s normal range is between 7 -56 units/ serum liter
- AST enzyme’s normal range is between 5-40 units/serum liter
- When enzyme levels are elevated two to three times higher than what is considered the normal range, these are said to be mild elevations. However, this sometimes depends on the laboratory’s preferred normal value range.
- In some cases, the liver enzymes elevation may become severe, reaching the 1000s range.
- The liver enzymes may get acutely elevated for a short period of time which may indicate that there’s been a sudden liver injury. It may also be acutely elevated for a long time indicating an ongoing injury of the liver.
- Apart from the duration, the abnormal liver enzyme elevation levels are also highly significant.
- A liver inflammation or mild injury could also lead to a mild elevation.
- Elevated enzyme levels reaching 10-20 times more than the normal enzyme level values suggest more severe liver damage.
As mentioned previously, ALT and AST are somewhat reliable ways to identify liver damage from diseases. Collectively, they are called liver blood tests or simply, liver tests.
However, as we also mentioned, elevated liver levels, especially AST enzymes, are not an express sign of the liver disease because it could indicate a different kind of tissue damage like muscle damage.
An interpretation of the normal liver function test is best done by a professional or expert physician that has proper experience evaluating the different kinds of tissue damage.
Causes of Elevated Liver Enzymes
- Fatty liver
- Hepatitis A or B
- Hepatitis B or C
- Chronic viral hepatitis
- Liver cirrhosis
- Alcohol abuse
- Reduced blood flow into the liver either from a heart failure or shock
- Hemochromatosis
- Medication overdose
- Pain medications
- Antibiotics like
- Medications for lowering cholesterol
- Anti-fungal medications,
- Psychiatric medications
- Tuberculosis medications
- Seizure medications
- Liver cancer
- Obesity
Signs and Symptoms of Liver Damage
When there are high enzyme levels in the blood, indicating liver damage, there may be little to mild symptoms. Sometimes though, these symptoms can get severe. Symptoms of liver damage include:
- Malaise
- Nausea and vomiting
- Loss of appetite
- Jaundice
- Abdominal Pain
- Weakness/Fatigue
- Itching
- Shortness of breath
- Swollen leg
- Excessive bruising/bleeding
What is a Liver Function Test?
A liver function test is a test that is employed to monitor and diagnose liver damage or disease. It monitors blood protein levels and most importantly, enzyme levels. There are different kinds of liver tests, some are used to measure normal kidney performance like how well its clearing waste and producing protein. Some other liver tests measure the presence of enzymes often released because of liver damage.
Liver function tests are also:
- Checks for liver infections like hepatitis
- Measures how severe liver disease is.
- Monitors the progression of liver diseases like alcoholic hepatitis, or viral hepatitis, and to also monitor the results of treatments
- Closely watch for side effects of medications.
Common Liver Function Tests
The first step to test liver function is to perform a blood test to measure liver enzyme levels. These enzymes are not usually found in the blood, they reside in the liver cells and only get released in the blood when there is a liver injury.
Other enzymes that may be measured during a liver test include gamma-glutamyl transpeptidase, alkaline phosphatase, and 5' nucleotidase.
These are some other liver function tests carried out to monitor liver function
- Coagulation panel and INR (International normalized ratio).
Measures the ability of the blood to clot normally, prevent bruising, and prevent bleeding.
- Bilirubin
Bilirubin is produced when red blood cells are destroyed in the liver. It is released normally in the feces as bile. Elevated levels of bilirubin indicate liver dysfunction.
- Albumin
This protein is usually found in the blood and produced in the liver alone. Reduced levels in the blood may be indicative of a liver disease. Of course liver damage is not the only cause of reduced albumin levels.
