ACE production occurs mainly in the epithelial cells of the pulmonary bed. Smaller amounts are found in blood vessels and renal tissue, where ACE converts angiotensin I to angiotensin II; this conversion helps regulate arterial blood pressure. Angiotensin II stimulates the adrenal cortex to produce aldosterone. Aldosterone helps the kidneys maintains water balance by retaining sodium and promoting the excretion of potassium.
Normal range: 8 " “53 U/L.
Use
Evaluation of patients with suspected sarcoidosis
Evaluate the severity and activity of sarcoidosis
Evaluation of hypertension
Evaluation of Gaucher disease
Interpretation
Increased In
Active pulmonary sarcoidosis (50 " “75% of patients but only 11% with inactive disease)
Gaucher disease (100%)
DM (>24%)
Hyperthyroidism (81%)
Leprosy (53%)
Chronic renal disease
Cirrhosis (25%)
Silicosis (>20%)
Berylliosis (75%)
Amyloidosis
TB infection
Connective tissue diseases
Fungal disease, histoplasmosis
Decreased In
Far-advanced lung neoplasms
Anorexia nervosa associated with hypothyroidism
COPD, emphysema, lung cancer, cystic fibrosis
Starvation
Limitations
False-positive rate equals 2 " “4%.
Levels may be normal in lymphoma and lung cancer.
Serum ACE is significantly reduced in patients on ACE inhibitors (e.g., enalapril and captopril).
The reference interval for children and adolescents may be as much as 50% higher than specimens from adults.
Serum ACE abnormality has been reported in 20 " “30% ofα1-antitrypsin variants (MZ, ZZ, and MS Pi types) but in only about 1% of individuals with normal MM Pi type. There is evidence that paraquat poisoning (because of its effect on pulmonary capillary endothelium) is associated with elevated serum ACE.