What to Know About the Aldolase Test

Medically Reviewed by Carol DerSarkissian, MD on May 25, 2021

The aldolase blood test (ALS) checks for muscle disease by measuring the level of aldolase in your blood.

What Is Aldolase?

‌Aldolase is a protein that helps the body turn sugar into energy. There is normally a lot of aldolase in your muscles and liver. When there is damage to the cells in your muscles or liver, those cells break open and dump the aldolase into your bloodstream.

Why Is an Aldolase Test Performed?

‌If you are experiencing muscle weakness or myalgia (muscle pain), your doctor will want to know if your symptoms are due to a problem with your muscles or your nerves. A high amount of aldolase (ALS) in your blood can be a sign of muscle damage. If the problem is in the nervous system, the amount of aldolase in your blood will not change.

How Do You Prepare for an Aldolase Test?

‌You may need to stop eating and drinking for about 8 hours before the blood test. Your doctor will let you know if you should stop any of your medicines to keep them from affecting the test results.

You might also need to avoid intense exercise for several days before the test. Long-lasting exercise can raise the level of aldolase in your blood and could affect your test results.

How Is an Aldolase Blood Test Performed?

‌A lab tech will place a very small needle in a vein in your arm. They will draw about 1 milliliter of blood into a little plastic tube called a vial. The vial will be sent off for testing. You will probably get results within a few days.

What Are Normal Results for an Aldolase Test?

‌The normal range for aldolase can be a little higher or lower depending on your age and gender. Generally, the normal range for adults is between 1.0 and 7.5 units per liter.

The normal amount of aldolase in the blood is higher in children. For those under age 18, anything under 14.5 units per liter is considered normal.

What Does it Mean if Your Aldolase Levels Are High?

‌An increased level of aldolase in the blood is sometimes a sign of muscle disease, such as:

Duchenne muscular dystrophy.Duchenne muscular dystrophy (DMD) is a genetic disorder, meaning it is the result of a difference in the person’s DNA. Symptoms typically start when a child is 2 or 3 years old. The first symptom is often muscle weakness, which can make it hard for the child to walk, run, and jump.

Other early signs can include delays in learning to sit, stand, or speak. Duchenne muscular dystrophy eventually causes muscle atrophy as well as heart and lung problems. Some medications can help manage the symptoms of DMD.

Limb-girdle muscular dystrophy. Limb-girdle muscular dystrophy is also a genetic disorder that causes weakness and wasting of the muscles around the shoulders and hips. Symptoms can include walking with a waddling gait, difficulty getting up out of a chair, or trouble climbing stairs.

The goal of treatment is to help ease symptoms. Treatment options include physical therapy and occupational therapy to strengthen muscles and prevent contractures, which are overly tight muscles that limit your range of motion.

Dermatomyositis.Dermatomyositis is an autoimmune disease, which means that the immune system is attacking healthy cells instead of just fighting off invaders like viruses.

Signs of dermatomyositis include a red rash around your eyelids, red or purple bumps on your joints, and muscle weakness in your arms and legs.

Polymyositis. Polymyositis is another rare autoimmune disease that also causes muscle weakness. Where dermatomyositis affects the muscles of the limbs, polymyositis typically causes weakness in the muscles of the neck, back, shoulders, and hips. It can also cause falls, a dry cough, and difficulty swallowing.

Symptoms most often start when you’re an adult and come on gradually. Medications can help reduce symptoms. Physical therapy can strengthen your muscles and improve your flexibility. Speech therapy can also help with swallowing difficulties associated with this condition.

WebMD Medical Reference



‌Genetic and Rare Diseases Information Center: “Dermatomyositis,” “Duchenne muscular dystrophy.”

International Journal of Sports Medicine: “Serum aldolase isoenzymes in athletes at rest and after long-lasting exercise.”

Johns Hopkins: “What Are Common Symptoms of Autoimmune Disease?”

Mayo Clinic: “Aldolase, Serum,” “Polymyositis.”

Muscular Dystrophy Association: “Duchenne Muscular Dystrophy (DMD),” “Limb-Girdle Muscular Dystrophy (LGMD).”

National Organization for Rare Disorders: “Limb-Girdle Muscular Dystrophies.”

The Myositis Association: “Blood Tests,” “Polymyositis.”

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