Test Details
Methodology
Quantitative spectrophotometry
Result Turnaround Time
4 - 5 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
Quantitative measurement of ACE in CSF. Angiotensin Converting Enzyme (ACE) is used in the assessment of neurosarcoidosis. The major sources of ACE are macrophages and epithelial cells. Patients with sarcoidosis display elevated levels of ACE.
Limitations
Results of this test are labeled for research purposes only by the assay's manufacturer. The performance characteristics of this assay have not been established by the manufacturer. The result should not be used for treatment or for diagnostic purposes without confirmation of the diagnosis by another medically established diagnostic product or procedure. The performance characteristics were determined by LabCorp.
Custom Additional Information
Angiotensin-converting enzyme catalyzes the formation of angiotensin II by cleaving the C-terminal histidylleucine dipeptide from angiotensin I.1
Indications are that ACE is affiliated with an autonomous renin-angiotensin system of the brain that participates in physiologic processes inside the brain.2,3 Also, studies suggest that changes in ACE concentrations in brain tissue, caused by various neurologic disorders, are reflected by alterations in ACE activity in cerebrospinal fluid (CSF).4
Increased ACE concentrations in CSF are associated with neurosarcoidosis,4-7 with affected patients generally having activities approximately two-fold or more higher than those of healthy individuals.4,6,7
Increased CSF ACE has also been implicated in neurologic diseases, such as bacterial and viral meningitis and Behcet disease.4-7
Decreased concentrations have been reported in patients with Alzheimer disease, Parkinson disease, and progressive supranuclear palsy.8,9
Specimen Requirements
Specimen
Cerebrospinal fluid (CSF), frozen
Volume
0.5 mL
Minimum Volume
0.2 mL
Container
Plastic (CSF) tube
Collection Instructions
Collect CSF by lumbar puncture.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Reference Range
See table.
Age | Range (U/L) |
|---|---|
0 to 5 y | Not established |
6 to 17 y | 0.0−2.1 |
18 to 50 y | 0.0−2.5 |
>50 y | 0.0−3.1 |
Storage Instructions
Transport frozen.
Causes for Rejection
Hemolysis
Footnotes
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 123231 | ACE, CSF | 12480-0 | 123232 | ACE, CSF | U/L | 12480-0 |
| Order Code | 123231 | |||||
| Order Code Name | ACE, CSF | |||||
| Order Loinc | 12480-0 | |||||
| Result Code | 123232 | |||||
| Result Code Name | ACE, CSF | |||||
| UofM | U/L | |||||
| Result LOINC | 12480-0 |