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Liver function tests, commonly known as a liver panel, are blood tests used to measure liver performance through the analysis of various substances found in the blood, such as proteins, enzymes, and bilirubin. The tests can provide important insight into problems with the liver, such as inflammation, scarring, or liver damage. They are often used to diagnose and monitor diseases, including hepatitis and cirrhosis.
There are a variety of different types of liver function tests, and each one screens for different aspects of liver health. Here’s a look at the most common types of liver function tests, as well as their normal ranges and what abnormal results may mean.
What is a liver function test?
A liver function test is a blood test used to measure various substances in the blood that are indicative of hepatic function. In a single appointment, your healthcare provider can gain a better overall picture of your liver health and make diagnoses or recommendations for further testing based on the results.
During the test, a small blood sample is taken from a vein in the arm using a small needle. The sample is then sent to the laboratory for analysis, and the results will be available within several days, or in some cases even sooner. Although your healthcare provider may recommend that you fast for 10 to 12 hours prior to the test, liver function tests generally don’t require any other preparation.
What does a liver function test show?
Your healthcare provider may recommend a liver function test for a variety of reasons. Generally, the test is ordered if you have any symptoms or signs that might indicate a problem with your liver, such as:
- Yellowing of the skin and eyes, a condition known as jaundice
- Upper abdominal pain or swelling
- Nausea or vomiting
- Fatigue
- Loss of appetite
- Dark urine or light-colored stool
In some cases, your healthcare provider may order a liver function test as part of routine screening or to monitor the progression of an existing condition.
“It’s generally recommended to get a liver panel if you’re diagnosed with obesity or being overweight, are a heavy alcohol drinker, have been exposed to hepatitis viruses, or have a genetic disposition for liver disease,” says Edward Salko, MD, a board-certified physician and a medical director at PersonaLabs.
The test results of a liver panel can also be used to help diagnose a variety of conditions, such as:
- Cirrhosis
- Hepatitis A, B, and C
- Liver cancer
- Nonalcoholic fatty liver disease
- Wilson disease
- Celiac disease
What’s included in a liver panel?
Based on your specific medical history and symptoms, your healthcare provider may order a number of different tests, explains Dr. Salko. Some common tests included in a liver function panel include:
- Alkaline phosphatase (ALP)
- Alanine transaminase (ALT), also known as alanine aminotransferase
- Aspartate aminotransferase (AST), also known as aspartate transaminase
- Gamma-glutamyl transferase (GGT), also known as gamma-glutamyl transpeptidase
- Albumin
- Total protein
- Bilirubin
- Lactate dehydrogenase (LDH)
- Prothrombin time (PT)
Liver function test normal range
The liver plays a role in nearly every bodily process, including metabolism, digestion, and immunity. As such, a healthy and properly functioning liver is important for overall health.
However, there are several factors that can affect how the liver functions, including age, sex, pregnancy, and certain medications, explains Dr. Salko. “Alcohol use, frequent eating out, and smoking cigarettes can also have adverse effects on the liver,” he adds.
Liver function test normal range chart |
|
|---|---|
| Test | Normal range |
| ALP | 30–120 U/L |
| ALT | 10–40 U/L |
| AST | 10–40 U/L |
| GGT | Female: 8–40 U/L
Male: 9–50 U/L |
| Albumin | 3.5–5.5 g/dL |
| Total protein | 5.5–9.0 g/dL |
| Bilirubin | Total: 0.3–1.0 mg/dL
Direct: 0.1–0.3 mg/dL Indirect: 0.2–0.7 mg/dL |
| LDH | 80–225 U/L |
| PT | 11–13 seconds |
Liver enzyme test
Liver enzyme lab tests measure the levels of certain enzymes in the blood that are released by liver cells. These enzymes help to speed up certain chemical reactions within the body, such as breaking down proteins and fats, helping blood clot, and fighting infection. Most commonly, doctors will order a test for four different enzymes:
- Alkaline phosphatase (ALP): 30–120 U/L
- Alanine transaminase (ALT): 10–40 U/L
- Aspartate aminotransferase (AST): 10–40 U/L
- Gamma-glutamyl transferase (GGT): 8–40 U/L for females, 9–50 U/L for males
“Elevations in both AST and ALT often mean that the liver is inflamed. The most common causes would include alcohol use, medications, fatty liver disease, and recent or current infections, such as COVID, mono, or other viruses,” says Max Pitman, MD, a medical director at Salvo Health and board-certified physician at Summit Health in Brooklyn, New York.
Abnormal levels of ALP could be an indicator of chronic liver disease, bone disease, or chronic kidney disease. However, additional laboratory tests are often needed to make the diagnosis.
“Elevated GGT can be seen in many conditions such as alcohol use, gallstone or gallbladder issues, and medication use,” Dr. Pitman says. “Elevated GGT on its own is not cause for immediate concern but should be evaluated in the context of other abnormal liver tests. Small increases in liver enzymes (two to five times the upper limit of normal) are often temporary and not cause for excessive concern but should be followed up to make sure that they decrease to the normal level over time.”
Albumin
Albumin is a protein produced in the liver, and it plays an important role in transporting various substances throughout the body, including hormones and medications. An albumin test measures the levels of serum albumin, with a normal range being 3.5–5.5 g/dL.
Elevated levels of albumin may be a sign of dehydration, while low levels can be indicative of liver or kidney disease. Dr. Pitman adds that low albumin can also be a sign of malnutrition or chronic inflammation.
Total protein test
The total protein test measures the total amount of proteins in your blood, including albumin and globulins. A normal range is typically 5.5–9.0 g/dL.
“Low total protein is a sign of malnutrition or chronic inflammation,” says Dr. Pitman. “Elevated total protein, particularly if it’s a very high level for a sustained period of time, should be checked out by your primary care physician or hematologist to make sure there is no underlying condition contributing to excess protein in the blood.”
Bilirubin test
Bilirubin is a yellow substance naturally made as your body breaks down old red blood cells. A healthy liver will automatically remove the majority of the bilirubin from your body as a waste product. However, if the liver is not functioning properly, bilirubin will build up in the bloodstream and cause the skin to yellow, a condition known as jaundice.
The normal range of serum bilirubin levels is 0.3–1.0 mg/dL. If your bilirubin levels exceed this range, it may be a sign of a liver condition, but this isn’t always the case—certain medications and foods can also elevate bilirubin levels.
LDH test
LDH, which plays an important role in energy production, is an enzyme present in the cells of almost all organs and tissue. A normal range for LDH levels is 80–225 U/L.
“Many different types of conditions can cause elevated LDH,” Dr. Pitman explains. “It’s not specific to any one condition. Some of these conditions involve inflammation, like infections, or rapid cell turnover, like in malignancy or certain types of anemia. Many other conditions can cause it as well, including autoimmune conditions, drug reactions, and much more.”
Dr. Pitman adds that a high LDH on its own should not cause concern, but it should be evaluated in context with other symptoms and tests.
Prothrombin time (PT) test
Prothrombin time refers to the time it takes for the liquid portion of your blood, also known as plasma, to clot. A normal prothrombin time should be within 11-13 seconds.
“Elevated PT means that blood clotting is not occurring as rapidly as normal and can indicate a risk of excessive bleeding,” Dr. Pitman says. “This is commonly seen in people who are taking blood thinners such as coumadin or Jantoven. It can also occur as a result of low vitamin K levels, certain inherited bleeding conditions, or in advanced liver disease, such as liver cirrhosis or acute liver failure.”
Next steps: What if I’m diagnosed with a liver condition?
Abnormal liver function test results can indicate a variety of liver conditions. While many of the symptoms of liver conditions are similar, the treatment will depend on the specific diagnosis.
Common types of liver conditions, symptoms, and treatments |
||
|---|---|---|
| Condition | Common symptoms | Treatments |
| Cirrhosis | Weakness, loss of appetite, unintentional weight loss, nausea, vomiting, mild pain in upper right side of abdomen, jaundice, itchy skin | Treatment of underlying cause, including drinking less alcohol, losing weight, and certain medications depending on underlying condition |
| Hepatitis A | Fever, loss of appetite, diarrhea, nausea, abdominal discomfort, dark urine, jaundice | No treatment, the virus will typically pass on its own |
| Hepatitis B | Fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, jaundice, joint pain | May clear on its own, or may require antiviral medication, such as entecavir or lamivudine |
| Hepatitis C | Fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, jaundice, joint pain | Antiviral and other medications, such as Epclusa or Pegasys |
| Liver cancer | Fatigue, loss of appetite, symptoms of indigestion, swollen abdomen, flu-like symptoms, jaundice | Chemotherapy, surgery, thermal ablation, radiotherapy |
| Nonalcoholic fatty liver disease | Generally few to no symptoms, tired, discomfort in upper right side of abdomen | Weight loss through healthy diet and exercise |
| Wilson disease | Fatigue, nausea, vomiting, poor appetite, dark urine, light-colored stool, pain in upper abdomen, jaundice, problems with speech, tremors, anxiety, depression, psychosis | Chelating agent medications, such as penicillamine and trientine |
| Celiac disease | Bloating, chronic diarrhea, constipation, gas, weight loss, mood changes, slowed growth, fatigue, joint pain, depression, anxiety | Gluten-free diet |
It’s important to address any and all concerns you may have with your healthcare provider, as they can provide you with the best information and advice on how to manage your condition, as well as potential side effects of each treatment option. Additionally, Dr. Salko advises that diet and lifestyle changes may help improve overall liver function, as well as have a positive impact on other aspects of your mental and physical health.
