What Is the Aldolase Test?

Aldolase is an enzyme responsible for breaking down certain sugars for energy. The liver and skeletal muscle tissue contain high levels of this enzyme. Aldolase testing may be done by a healthcare provider who suspects a muscular problem, such as muscle pain or weakness. Aldolase is released when muscles get damaged, so a person with muscular problems will have higher levels of aldolase.

Read on to learn why the aldolase test is performed and what an abnormal level could mean.

Aldolase Test Uses

Your healthcare provider may order an aldolase test when they suspect certain muscle disorders. The aldolase test can also help determine the causes of muscle weakness (myopathy). If the cause of muscle weakness is neurologic (related to the nervous system) aldolase levels will not be elevated, while if a muscular problem causes the weakness, aldolase levels will be elevated.

The aldolase test may be ordered if you are experiencing muscle weakness or pain. However, the test is nonspecific, meaning that it does not indicate an exact diagnosis. For example, based on this test alone, you cannot differentiate between a liver or a muscle problem. However, in combination with other tests, an aldolase test can help guide further testing to determine the cause of muscle symptoms.

Aldolase Test Procedure

The aldolase test is a blood test and requires venipuncture (drawing blood from a vein). A vein in the arm is typically used, and the overlying skin is cleaned. An elastic band is then wrapped around the upper arm to make the vein plump and easier to puncture. Then a needle is placed into the vein, and blood is collected in a tube, which is then sent for laboratory testing.

What to Expect

Before you have a blood draw for the aldolase test, you may be asked to fast and avoid exercise for a certain period of time, since exercise can transiently increase aldolase levels.

The aldolase test, like any blood draw, may cause mild pain, bleeding, and bruising at the puncture site. Some people experience nausea or feel faint with blood draws. If you feel dizzy, notify the technician, who may ask you to lie down or provide water for you to drink. You should also notify your healthcare provider if you develop signs of infection, like redness, warmth, pain, and swelling at the puncture site.

Test results can take anywhere from hours to a few days.

Interpreting Results

Elevated levels of aldolase in the blood may be caused by various muscle or liver problems. Other diagnostic tests are performed to arrive at a correct diagnosis.

The normal range of aldolase in the blood can vary between the specific laboratory, but in general, a normal aldolase level in adults is between 1 and 7.5 units per liter. Levels may be slightly higher in men, and are higher in infants and children.

Causes of High Aldolase Levels

Any problem with muscles can lead to elevated aldolase levels. Some specific conditions are classically associated with elevated levels, and when these conditions are suspected, aldolase tests are often ordered.

Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is an inherited muscle disorder, typically diagnosed in childhood. Due to the genetics of the condition (X-linked recessive), this condition occurs in males. In this condition, muscles become progressively weak, starting in the shoulder and pelvic regions, and spreading throughout the body. This leads to difficulty walking, standing, and even falls. In later stages, the heart muscle can be affected, leading to cardiomyopathy (heart muscle weakness).

If muscular dystrophy is suspected, an aldolase lab test is performed. Levels of aldolase in DMD may be very elevated, due to the widespread muscle damage in this condition.

Limb-Girdle Muscular Dystrophy

Another type of muscular dystrophy that is less common than DMD is limb-girdle muscular dystrophy (LGMD). This is a group of muscular dystrophies with varying symptoms, severity, and age of onset caused by genetic mutations. LGMD is marked by muscle weakness in the shoulders, upper arms, hips, and legs. Aldolase levels in LGMD are elevated.

Dermatomyositis

Dermatomyositis is an inflammatory condition that causes skin rash and muscle weakness. Although the symptoms of dermatomyositis vary, it causes soreness and weakness that will affect the muscles in the upper arms, legs, shoulders, and hips. A rash can appear on the face, hands, arms, and skin overlying joints. Symptoms often come and go.

Inflammation of the muscles results in the elevation of aldolase levels. And the elevation of aldolase is one of the criteria for diagnosing dermatomyositis.

Polymyositis

Similar to dermatomyositis, polymyositis is an inflammatory condition affecting the muscles, causing them to become weaker. It does not typically cause a skin rash. Aldolase and other muscle enzymes are elevated in polymyositis, which is the criteria for diagnosing this condition. Muscle biopsy is often required for a definitive diagnosis.

Summary

Aldolase is an enzyme found in high levels in muscle and liver tissue that is elevated in certain conditions. A healthcare provider may order this test, along with other testing, when a muscle condition is suspected. The aldolase test is performed with a blood draw. Because it is nonspecific, meaning it is not tied to just one condition, other lab tests, imaging studies, and muscle biopsy may be performed to arrive at a diagnosis.

A Word From Verywell

Having muscle pain and weakness is not only unpleasant but can be confusing and frustrating when you are trying to figure out what is wrong. Many conditions can cause these symptoms. Getting lab tests, including an aldolase test, is one of the first steps in figuring out the cause.