DefinitionACE levels is a blood test that measures the amount of angiotensin-converting enzyme (ACE).
Alternative NamesSerum angiotensin-converting enzyme; SACE
How the test is performedA blood sample is needed. For information on how this is done, see: Venipuncture
How to prepare for the testYou may have to restrict food and fluids for up to 12 hours before the test. People taking steroid therapy should talk to their health care providers, because steroids can decrease ACE levels.
How the test will feelWhen 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 performedThe most common use of this test is to help diagnose and monitor a disorder called sarcoidosis . People with sarcoidosis may have their ACE levels tested regularly to check the severity of the disease and see how well treatment is working. This test also helps confirm Gaucher's disease and leprosy.
Normal ValuesNormal values vary based on your age and the test method used. Typically, adults have ACE levels less than 40 micrograms/L.The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What abnormal results meanIncreased ACE levels may be a sign of sarcoidosis. ACE levels will rise or fall as sarcoidosis becomes worse or improves.However, increased ACE levels may also be seen in several other disorders, including:Active histoplasmosisAlcoholic hepatitisAsbestosisAsthmaBerylliosisDiabetesEmphysemaGaucher's diseaseHodgkin's diseaseHyperthyroidismIdiopathic pulmonary fibrosisLeprosyLung cancerMultiple sclerosisNephrotic syndromeSilicosisTuberculosisA decrease in ACE levels may indicate:Anorexia nervosaChronic liver diseaseSteroid therapy (usually prednisone)Therapy for sarcoidosisUnderactive thyroid (hypothyroidism)
What the risks areVeins 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.The risks associated with having blood drawn are slight but may include:Excessive bleedingFainting or feeling lightheadedHematoma (blood accumulating under the skin)Infection (a slight risk any time the skin is broken)
Special considerationsBecause elevated ACE levels may also be seen in several other disorders, the overall usefulness of the ACE blood test is limited.
ReferencesPincus MR, Abraham NZ, Carty RP. Clinical enzymology. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 20.Iannuzzi M. Sarcoidosis. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 95.