ACE levels

• Illustrations
• Alternative names
• Definition
• How the test is performed
• How to prepare for the test
• How the test will feel

• Why the test is performed
• Normal Values
• What abnormal results mean
• What the risks are
• Special considerations

Alternative names    Return to top

Definition    Return to top

This is a blood test that measures the amount of angiotensin-converting enzyme (ACE).

How the test is performed    Return to top

Blood is drawn from a vein on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to fill with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

For an infant or young child:

The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.

Blood is drawn from a vein on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to fill with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

For an infant or young child, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.

After the blood has been drawn, it is sent to a laboratory to be evaluated.

How to prepare for the test    Return to top

Food and fluids may be restricted for up to 12 hours before the test. People taking steroid therapy should consult their health care providers because steroids can decrease ACE levels.

For infants and children:

The preparation you can provide for this test depends on your child's age and experience. For specific information regarding how you can prepare your child, see the following topics:

• infant test or procedure preparation (birth to 1 year)
• toddler test or procedure preparation (1 to 3 years)
• preschooler test or procedure preparation (3 to 6 years)
• schoolage test or procedure preparation (6 to 12 years)
• adolescent test or procedure preparation (12 to 18 years)

How the test will feel    Return to top

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed    Return to top

ACE levels can be used in the evaluation of sarcoidosis and other diseases that are caused or aggravated by constricted blood vessels. People with sarcoidosis may have their ACE levels tested regularly to evaluate the severity of the disease and to monitor the response to therapy. This test also helps confirm Gaucher's disease and leprosy.

Normal Values    Return to top

Normal values vary with age and with the test method used. Typically, adults have ACE levels less than 40 micrograms/L.

What abnormal results mean    Return to top

This test is often used to help diagnose sarcoidosis, a condition in which ACE levels are increased 75% of the time. Elevated ACE levels may also be seen in several other disorders, including:

• active histoplasmosis
• alcoholic cirrhosis
• amyloidosis
• asbestosis
• berylliosis
• diabetes mellitus
• Gaucher's disease
• Hodgkin's disease
• hyperthyroidism
• idiopathic pulmonary fibrosis
• leprosy
• myeloma
• primary biliary cirrhosis
• pulmonary embolism
• scleroderma
• silicosis
• tuberculosis

• steroid therapy (usually prednisone)
• response to therapy for sarcoidosis

What the risks are    Return to top

The risks associated with having blood drawn are:

• excessive bleeding
• fainting or feeling light-headed
• hematoma (blood accumulating under the skin)
• infection (a slight risk any time the skin is broken)
• multiple punctures to locate veins

Special considerations    Return to top

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.