Angiotensin-converting Enzyme (ACE)
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.
Special Instructions
Stop administration of captopril, enalapril, or lisinopril 12 hours prior to venipuncture to reduce ACE activity.
Limitations
Elevations of ACE levels are observed in approximately 35% to 80% of sarcoidosis cases, and less likely in chronic cases. Different mixtures of acute and chronic cases contribute to variability in elevation incidence reports. Elevated ACE levels have also been reported in other conditions, including diabetes mellitus, Gaucher disease, leprosy, primary biliary cirrhosis, amyloidosis, myeloma, some alpha1-antitrypsin variants, Melkersson-Rosenthal syndrome, and hyperthyroidism. The test is not specific for sarcoidosis, as elevations may occur in conditions like extrinsic allergic alveolitis, coccidioidomycosis, beryllium disease, asbestosis, silicosis, and alcoholic liver disease. ACE activity decreases during starvation, regardless of thyroid activity levels, and may also be normal in bronchogenic carcinoma responding to treatment.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 2742-5
- 2742-5
Result Turnaround Time
2-3 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
0.5 mL
Minimum Volume
0.2 mL
Container
Red-top tube or gel-barrier tube
Collection Instructions
Separate serum from cells at the time of collection.
Patient Preparation
Stop administration of captopril, enalapril, or lisinopril for 12 hours prior to venipuncture (reduces ACE activity).
Storage Instructions
Room temperature
Causes for Rejection
Captopril, enalapril, or lisinopril administration; hemolyzed or icteric specimen; whole blood, cerebrospinal fluid (CSF), or EDTA plasma specimen received
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 10 days (stability provided by manufacturer or literature reference) |
| Refrigerated | 10 days (stability provided by manufacturer or literature reference) |
| Frozen | 7 months (stability provided by manufacturer or literature reference) |