Your Guide to Liver Lab Tests and Liver Function Test Interpretation

Research shows that 4.5 million adults live with diagnosed liver disease, totaling around 1.8% of the population. 

If you’re one of those affected, you know how debilitating liver disease can be. 

You also know that staying on top of your health can make a world of difference. Whether you’re already suffering from reduced liver function or you’re at risk of developing it, it’s important to get check-ups periodically.

Yet, lab tests can be notoriously complex. How do you know which ones to take and what the results mean? Today, we’re sharing a liver function test interpretation guide to take the guesswork out of the equation. 

Read on to learn which tests to prioritize and how to understand the answers you receive. 

Liver Disease 101

Did you know that your liver is the largest organ inside of your body? And, it serves an equally large purpose. 

Your liver is responsible for helping your body digest food, remove toxins, and store energy. It’s also susceptible to disease.

There are multiple kinds of liver disease caused by one of four culprits: viruses, drug abuse, cancer or genetics. Let’s take a look at some of the most common diseases under each type.

Viruses

Liver diseases caused by viruses include Hepatitis A, B, and C. Note that most cases of Hepatitis A infections are short-term. On the other hand, Hepatitis B and C can lead to longer-term, or chronic, infections.

Drug Abuse

If you misuse drugs, poisons, or alcohol, the toxins in these substances can damage your liver. Examples of liver diseases in this category include cirrhosis (scarring of the liver) and fatty liver disease. 

Liver Cancer

Liver cancer affects up to 33,000 new people in the U.S. every year. Moreover, 27,000 people in the country die from the disease every year. Many cases of liver cancer stem back to Hepatitis B or Hepatitis C viruses or infections. 

Inherited Diseases

While many instances of liver disease can be traced back to environmental or behavioral factors, there are also inherited diseases that can affect your liver function. 

These include hemochromatosis, defined as overage of iron in your body, as well as Wilson’s disease, defined by an overage of copper in your organs. 

Symptoms of Liver Disease

As there are many different variations of liver disease, it can be difficult to pinpoint exact symptoms. However, there are a few common signs that can help physicians point to an issue. 

These include:

  • Swelling in your abdomen and legs
  • Variations in your stool and urine color
  • Bruises that appear easily
  • Jaundice 

Nine Liver Function Test Interpretation Metrics

It’s important to note that liver disease can strike without any symptoms. This is why liver function tests are so important. They’re used to check for liver damage and can also help diagnose liver diseases.

Now, let’s take a look at nine key liver function tests that anyone at risk for liver disease should undergo.

Alanine Aminotransferase (ALT)

This is a critical lab test that checks for liver damage. If you’re wondering whether a disease, drug use, or injury has caused damage to your liver, an Alanine Aminotransferase (ALT) test can get to the root of the issue. 

The ALT enzyme is mostly concentrated in your liver. It helps your body break down food and turn it into energy. On a normal basis, there are only minimal traces of ALT in your blood.

Normal levels of ALT are between 7 and 56 units-per-liter (U/L) of serum.

A damaged liver will release more ALT back into your bloodstream. If your levels come back higher than normal on an ALT test, it could signal that there’s an issue with your liver’s performance. 

Alkaline Phosphatase (ALP)

Like ALT, Alkaline Phosphatase (ALP) is another important enzyme located primarily in your liver, though it’s also present in your digestive system, kidneys, and bones. It helps your body break down proteins. 

An ALP test will measure the amount of this enzyme present in your blood. 

If you’re experiencing liver damage, your liver will release high levels of ALP into your blood. Normal ALP levels are between 20 and 140 U/L.

Aspartate Aminotransferase (AST)

Another important enzyme, Aspartate Aminotransferase (AST), releases into your bloodstream when you experience damage to your liver. 

In most cases, normal AST amounts are between 10 to 40 U/L. If your levels are abnormally high, it might be a sign of liver damage or disease. 

Bilirubin

Bilirubin is a yellowish substance that occurs naturally as portions of your red blood cells break down. As it’s released, your liver accepts the bilirubin from your blood. Then, it alters its chemical makeup enough that you can eliminate it as bile. 

If you’re experiencing jaundice, it’s important to schedule a bilirubin lab test. If your results come back high, it can mean one of two things:

  1. Your red blood cells are breaking down in an unusual way
  2. Your liver isn’t breaking down waste as it should. 

Either way, your body is unable to clear the bilirubin from your blood. This can result in a yellowing of your skin and eyes. Normal adults over the age of 18 can have up to 1.2 milligrams of bilirubin per deciliter (mg/dl) of blood. High levels can point to compromised liver function. 

Albumin

Albumin is a protein that your liver creates. Your body uses it to carry hormones, enzymes, and medicines throughout your body.

Normal albumin levels range from 3.4 to 5.4 g/dL. If your levels are lower than this, it could mean you have liver disease.

Total Protein and Albumin/Globulin (A/G) Ratio

You may already know that proteins are essential building blocks present within all your cells and tissues. They provide critical support to your overall growth, health, and development. 

Within your blood, there are two specific kinds of proteins. These include albumin (detailed above) and globulins. Albumin comprises around 60% of the protein and globulins supply the remaining 40%.

Your Total Protein and Albumin/Globulin (A/G) Ratio test will measure the total protein present in your blood, along with individual levels of albumin. You can calculate the number of globulins by subtracting the albumin from the total protein amount. This is the A/G ratio.

Normally, you’ll have a slightly higher level of albumin than globulins, and the ratio will measure a little over 1. If there’s an issue with your liver, this ratio can help pinpoint where it originates.

The Hepatic Function Panel contains each of the six biomarkers noted above.

The Hepatic Function Panel, also known as the Liver Function Panel, contains the following 10 biomarkers:

  • Albumin
  • Albumin/Globulin Ratio
  • Alkaline Phosphatase
  • ALT
  • AST
  • Bilirubin, Direct
  • Bilirubin, Indirect
  • Bilirubin, Total
  • Globulin
  • Protein, Total

Gamma-Glutamyl Transferase (GGT)

The Gamma-Glutamyl Transferase (GGT) enzyme is in your liver. If a disease strikes your liver or bile ducts, most GGT tests will return with results that are higher than normal. 

Average GGT levels are 9 to 48 U/L, although these levels can rise in the event of liver damage. This test is especially useful in identifying and diagnosing bile duct concerns. GGT is one of the fastest-acting enzymes to rise in your blood in the event of a bile duct obstruction. 

Prothrombin Time and International Normalized Ratio (PT/INR)

Let’s break down this test name into two parts.

First, Prothrombin Time and International Normalized Ratio (PT/INR) is a measure of how long it takes for your body to form blood clots. Also, INR is a separate test performed on individuals who are currently taking blood-thinning medication.

For reference, an average PT is around 11 to 13.5 seconds and an average INR is 0.8 to 1.1

Lactate Dehydrogenase (LD)

Almost every cell in your body contains at least some level of Lactate Dehydrogenase (LD). The highest concentrations are in your heart, liver, kidney, lung, muscles, and erythrocytes.

This enzyme is the powerhouse behind your ability to convert sugar into energy

The levels to look for are between 140 U/L to 280 U/L for adults. If you’ve experienced tissue damage, your levels will be abnormally high, which is cause for concern.

Lab Tests to Screen and Monitor Individuals

In addition to the nine key labs tests identified, we also want to share a list of nine other lab tests designed to help those with poor liver health or reduced liver function.

If you’re included in this group, you should get your blood level tested periodically to stay on top of any changes in your health.

Alpha-1 Antitrypsin

Medical research links AAT deficiencies with liver disease. This condition, known as Alpha-1, makes the AAT protein in your liver work at low capacity. 

In normal cases, this protein travels through your liver and into your blood, where it helps protect your lungs and other valuable organs. If the protein has an abnormal shape, it can get lodged in your liver.

Once the protein lodges in your liver, it can cause a multitude of conditions ranging from cirrhosis to liver cancer. You may also experience lung issues. An AAT test helps measure the amount of AAT in your blood and can also reveal if you’ve inherited any abnormal forms of the protein. A standard range is 100-300 mg/dL and levels lower than 80 mg/dL can mean a heightened risk of lung disease.

Alpha-Fetoprotein (AFP) Tumor Marker

Produced in a fetus’ liver and yolk sac, Alpha-Fetoprotein (AFP) Tumor Marker plays a critical role in early development. It’s the main protein present at this time. 

By your first birthday, AFP levels drop significantly and by the time you’re an adult, there are only traces of it in your blood.

That said, AFP is a tumor marker.

These are molecules in your blood that become present in higher capacities if there is an instance of cancer. This particular marker links to liver cancer. Also, higher blood levels of AFP are present in cases of cirrhosis or chronic active hepatitis. 

While an AFP blood test will determine your exact levels, tests measure the standard range for adults in nanograms, equaling less than 10 ng/mL. If your test comes back extremely high (e.g. 400ng/ml) it could indicate liver tumors. 

Ceruloplasmin

Remember our mention of Wilson’s disease? This inherited disease negatively affects your liver. Ceruloplasmin is an enzyme that contains copper and plays a major role in your body’s iron metabolism. 

Once your intestines absorb copper from food, they send it to your liver. There, it’s stored or sent to help make different kinds of enzymes. Your liver then connects Ceruloplasmin to a protein and sends it into your bloodstream. As such, more than 90% of the copper in your body is bound to Ceruloplasmin.

If your liver becomes damaged or diseased, it can get overrun with copper and unable to process it all, leading to Wilson’s disease. Most people have Ceruloplasmin serum levels of 20 to 35 mg/dl. Most people suffering from Wilson’s disease will have lower levels of 10 mg/dL instead.

Along with urine tests, a Ceruloplasmin blood test can help you identify if you’re at risk for this condition. 

Copper

As expected, a copper blood test will reveal the level of copper present in your blood. Most adults have between 50mg and 80mg of copper present within their body, with most of it stored in their liver and muscle tissue. 

This test provides another way to test for Wilson’s disease, which leads to a copper buildup that eventually overflows from your liver, entering your brain, kidneys, and even your eyes. 

In the process, the excess copper can kill your liver cells and result in long-term nerve damage.

Des-Gamma-Carboxy Prothrombin (DCP) 

Prothrombin is a clotting factor that your liver produces. In its abnormal state, it can become Des-Gamma-Carboxy Prothrombin (DCP).

If you’re currently undergoing treatment for a certain kind of liver cancer called hepatocellular carcinoma (HCC), a DCP test can help reveal if that approach is yielding the intended results. 

Also, liver tumors will produce DCP, explaining why these levels are checked alongside AFP. 

Iron and Total Iron Binding Capacity (TIBC)

An Iron and Total Iron Binding Capacity (TIBC) test measures the amount of iron in your blood. Most people get all the iron they need from their diet alone. Once you ingest it, a protein called transferrin carries it to through your bloodstream. 

Your liver produces transferrin, and a TIBC test will measure how well transferrin binds to iron and carries it throughout your blood. Most laboratories define a normal TIBC range of between 240 and 450 mcg/dl. If your levels are higher than this, it denotes a low level of iron in your blood.

Hepatitis A Testing

Hepatitis A is a very contagious infection that affects your liver. As detailed, it’s one of a few cases of hepatitis, all of which lead to an inflamed and enlarged liver. 

When any form of hepatitis compromises your liver, it’s unable to perform its job. This means that toxins and waste products build up without a way to exit your body.

Hepatitis A Testing can determine if this virus is present in your body. If your Hepatitis A IgM antibody delivers a “positive” result, it indicates a recent or acute infection.

Hepatitis B Testing

Hepatitis B is another liver infection. This virus can damage the cells in your liver, causing your liver enzymes to leak into your bloodstream. 

Hepatitis B Testing can determine if this virus is present in your body. If your Hepatitis B Surface Antigen (HBsAg) antibody delivers a “positive” result, it indicates that you have a new infection or a flare of a chronic Hepatitis B infection.

Hepatitis C Testing

Hepatitis C is another infection that affects your liver, causing inflammation and potential liver damage. 

Hepatitis C Testing can determine if you have such an infection. If your Hepatitis C antibody delivers a “positive” result, it indicates that you have an infection. In 50% to 80% of cases, an initial infection accelerates to a chronic infection. 

Proactive Testing Protects Your Liver Health

If you suffer from liver disease, you know that it can be a silent but painful condition. Also, there are so many facets that it can be challenging to pinpoint your exact condition or risk factor.

If you need help understanding the health of your liver, we’d love to help. We offer these key liver lab tests as part of our selection of 1,500 lab tests, and we provide explanations on each biomarker.

You can select your lab tests, order directly online, choose a convenient patient service center near you, and review your test results typically in 1 to 2 days after your blood is collected.

Take charge of your health and get tested today at UltaLabTests.com/Shop

Contact us today to learn more and find the answers you’re looking for.