Liver Function Panel: AST, ALT, and What Your Results Mean

What Is a Liver Function Panel?

A liver function panel is a set of blood tests that check how your liver is working. The liver is a large organ that filters toxins, processes nutrients, stores energy, and makes proteins and bile. Because it does so many jobs, a panel uses several markers to build a picture rather than relying on one number.

A typical panel includes enzymes such as AST, ALT, and alkaline phosphatase, plus proteins such as albumin and total protein, and bilirubin. Some versions also include GGT or a prothrombin time. The exact list depends on the laboratory and the ordering reason.

The word panel matters. A single enzyme can be high for reasons unrelated to liver disease, so clinicians read the markers together, along with your history and other tests, before drawing conclusions.

What Each Liver Marker Measures

• AST: an enzyme found in the liver, heart, and muscle. High levels can come from liver stress or muscle injury.
• ALT: an enzyme more specific to the liver, so it is often the clearer signal of liver irritation.
• Alkaline phosphatase: an enzyme linked to bile ducts and bone.
• Bilirubin: a yellow pigment from red blood cell breakdown that the liver processes.
• Albumin: a protein the liver makes that keeps fluid in the blood vessels.
• Total protein: the combined amount of albumin and other blood proteins.

An AST and ALT pattern, plus bilirubin and albumin, often tells a clinician whether the issue is sudden or long-standing.

What Normal and Abnormal Liver Panel Results Mean

Reference ranges vary by laboratory, so check your own report. Common adult guides are:

High AST and ALT often point to liver cell irritation from fatty liver, alcohol, medication, or a viral infection. A high alkaline phosphatase can suggest a bile duct problem. Rising bilirubin can cause jaundice. Low albumin can reflect a long-term liver or nutrition issue. Because many factors shift these markers, an abnormal panel is a starting point for more questions, not a final answer.

Why a Liver Function Panel Is Ordered

A liver panel is ordered to:

• Screen for liver problems as part of routine blood work
• Investigate fatigue, nausea, abdominal pain, or jaundice
• Monitor a known liver condition or medication effect
• Check for fatty liver disease related to weight or metabolic health
• Follow up on abnormal results from another panel

It is often paired with a comprehensive metabolic panel, a complete blood count, and hepatitis testing when a viral cause is possible.

How to Order a Liver Function Panel and Where to Get Tested

You can order a liver panel without a doctor's visit in most US states. Online lab-testing directories let you select a liver panel, pay, and download a requisition. You then visit a CLIA-certified lab or one of our partner lab locations for a blood draw, usually without an appointment.

1. Choose a liver function panel or a metabolic panel that includes it.
2. Pay online and print your requisition.
3. Visit a nearby walk-in testing site.
4. View results in a secure portal, often within one to two business days.

Tell the lab about any medications, supplements, or alcohol use, since these can change liver enzyme levels.

How Much Does a Liver Function Panel Cost?

A liver function panel commonly costs between about $40 and $90 through a direct-access lab. A broader comprehensive metabolic panel that includes liver markers usually runs $25 to $90. Insurance may cover testing when a clinician documents a medical reason.

Preparation and What to Expect

Some liver panels are done fasting, especially when they are part of a metabolic panel. Avoid heavy alcohol use and strenuous exercise for a day before the draw, since both can raise liver enzymes. The blood draw takes only a few minutes.

If results are abnormal, a clinician may repeat the panel to see whether the change persists, then order imaging or viral testing if needed.

Liver enzymes can rise for reasons that have nothing to do with liver disease. Intense exercise, a recent injury, and even some common pain relievers can raise AST or ALT. Because of that, a mildly abnormal panel is often repeated before any imaging or further testing is ordered.

Keeping a copy of your past results helps. A number that has been stable for years carries a different meaning than the same number after a recent jump, and the pattern over time guides the next step.