| Subject | Contents |
| Definition | A test that measures the amount of angiotensin-converting enzyme (ACE) in the blood. |
| Alternative Names | Serum angiotensin-converting enzyme; SACE |
| How the test is performed | Adult or child: Blood is drawn from a vein ( venipuncture ), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (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 tourniquet 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 . 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 | 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. Infants and children: The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age: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 | 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 | 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 | Normal results range from 18 to 67 U/ml for individuals over 20 years old. People under 20 years old have higher ACE levels and are not usually tested. Note: U/ml = units per milliliter |
| What abnormal results mean | Abnormal results may be indicated by increased levels that are seen in about 75% of patients with sarcoidosis . However, elevated levels may also be seen in several other disorders including: active histoplasmosis alcoholic cirrhosisamyloidosisasbestosis berylliosis diabetes mellitus Gaucher's disease Hodgkin's diseasehyperthyroidismidiopathic pulmonary fibrosisleprosy myeloma primary biliary cirrhosispulmonary embolismsclerodermasilicosistuberculosis A decrease in ACE levels may indicate: steroid therapy (usually prednisone) response to therapy for sarcoidosis |
| What the risks are | excessive bleedingfainting 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 | 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. |
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