Angiotensin-Converting Enzyme (ACE)

Test ID: 

702780

CPT code:

82164

Clinical Use:

High in sarcoidosis, more often when the disease is active. Of value in assessing the response of sarcoidosis to corticosteroid therapy. Changes in serum ACE correlate with clinical status and results of gallium scans (which reflect presence and activity of inflammatory granulomatous lesions). Falling ACE level is a favorable prognostic sign. Rising levels may reflect activity uncontrolled by therapy.

Test Information:

Other abnormalities found in some sarcoidosis patients include elevations of serum alkaline phosphatase, calcium, gamma globulin with polyclonal gammopathy, and hypercalciuria. Serum angiotensin converting enzyme is elevated in 50% of cases of sarcoidosis but not in cases of active tuberculosis or Hodgkin disease. Increases are less frequent when sarcoidosis is inactive.6 Some 80% to 90% of patients with demonstrably active sarcoidosis have elevated serum ACE. Angiotensin converting enzyme activity is also increased in sarcoid lymph node homogenate. The diagnosis of sarcoidosis is an histopathologic/clinical complex. Noncaseating granulomas must be proven not to be caused by tuberculosis, histoplasmosis, or other microbiologic entities. Berylliosis is a very rare cause of such granulomas.

Specimen Type:

Serum

Requested Volume: 

0.5 mL

Minimum Volume: 

.02 mL

Container Type: 

Red-top tube or gel-barrier tube

Patient Preparation: 

Stop administration of captopril, enalapril, or lisinopril for 12 hours prior to venipuncture (reduces ACE activity).

Collection:

Separate serum from cells.

Storage Instructions:

Room Temperature.

Stability Requirements:

Rejection Criteria

Captopril, enalapril, or lisinopril administration; hemolyzed or icteric specimen; whole blood, cerebrospinal fluid (CSF), or EDTA plasma specimen received.