Home
HelpTest Code ACE Angiotensin Converting Enzyme, Serum
Reporting Name
Angiotensin Converting Enzyme, SUseful For
Evaluation of patients with suspected sarcoidosis
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumNecessary Information
The use of angiotensin converting enzyme (ACE)-inhibiting antihypertensive drugs will cause decreased ACE values. Patients taking ACE inhibitors, such as captopril and enalapril, will have extremely low or unmeasurable ACE activity. Indicate on the request form if the patient is on ACE inhibitors.
Specimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 7 days | |
| Frozen | 180 days | ||
| Ambient | 24 hours |
Reference Values
≥18 years: 16-85 U/L
0-17 years: Angiotensin converting enzyme activity may be 20-50% higher in healthy children compared to healthy adults.
For SI unit Reference Values, see https://www.mayocliniclabs.com/order-tests/si-unit-conversion.html
Day(s) Performed
Monday through Friday
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
82164
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| ACE | Angiotensin Converting Enzyme, S | 2742-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| ACE | Angiotensin Converting Enzyme, S | 2742-5 |
Clinical Information
Angiotensin converting enzyme (ACE) is integral to the renin-angiotensin system (RAS), which maintains blood pressure by regulation of fluid volume and vascular tension. Its peptidase action on the decapeptide angiotensinogen I results in the hydrolysis of a terminal histidyl leucine dipeptide and the formation of the octapeptide angiotensin II, a potent vasoconstrictor that increases blood pressure.
ACE activity is increased in sarcoidosis, a systemic granulomatous disease that commonly affects the lungs. In sarcoidosis, ACE is thought to be produced by epithelioid cells and macrophages of the granuloma.
ACE activity reflects the severity of sarcoidosis: 68% positivity in those with stage I sarcoidosis, 86% in stage II sarcoidosis, and 91% in stage III sarcoidosis.
Other conditions such as Gaucher disease, leprosy, untreated hyperthyroidism, psoriasis, premature infants with respiratory distress syndrome, adults with amyloidosis, and histoplasmosis have been associated with increased serum ACE activity.
Interpretation
An elevation in the level of serum angiotensin converting enzyme (ACE), along with radiographic evidence of infiltrates or adenopathy and organ biopsies showing noncaseating epithelial granulomas is suggestive of a diagnosis of sarcoidosis.
Normal, healthy children and infants are known to have ACE activity levels greater than the adult reference interval.
Cautions
Spinal fluid angiotensin converting enzyme (ACE) activity to aid the diagnosis of neurosarcoidosis has been reported; however, there is insufficient evidence to support ACE being used for this purpose.
Clinical Reference
1. Liebermann J: Elevation of serum angiotensin-converting-enzyme (ACE) level in sarcoidosis. Am J Med. 1975;59:365-372
2. Rodriguez GE, Shin BC, Abernathy RS, Kendig EL Jr: Serum angiotensin-converting enzyme activity in normal children and in those with sarcoidosis. J Pediatr. 1981;99:68-72
3. Personal observations from a Mayo pediatric normal range study using a manual method (Hana)
4. Maguire GA, Price CP: A continuous monitoring spectrophotometric method for the measurement of angiotensin-converting enzyme in human serum. Ann Clin Biochem. 1985;22:204-210
5. Allen DW, Rajagopal V: Other adjunctive drugs for coronary intervention: beta-blockers, calcium-channel blockers, and angiotensin-converting enzyme inhibitors. In: Tropol EJ, Teirstein P, eds. Textbook of Interventional Cardiology. 8th ed. Elsevier; 2020:214-222
Method Description
Angiotensin converting enzyme (ACE) catalyzes the conversion of angiotensin I to angiotensin II. The enzyme also mediates the cleavage of the synthetic substrate N-(3-[2-furyl]acryloyl)-L-phenylalanylglycylglycine (FAPGG) into an amino acid derivative and a dipeptide. The kinetic of this cleavage reaction is measured by recording the decrease in absorbance at 340 nm.(Package insert: Buhlmann ACE Kinetic; 01/2013)
Report Available
1 to 3 daysSpecimen Retention Time
7 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Disease States
- Sarcoidosis
Method Name
Spectrophotometry (SP)
Forms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-General Request (T239)
-Cardiovascular Test Request (T724)