Support diagnosis of neurosarcoidosis. May be used to evaluate treatment response.

Sterile vial/container

1. Transfer CSF to a Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp), labelled as CSF
2. Freeze

Screw-cap polypropylene frozen transport vial/tube - 4mL (LabCorp)

Frozen (preferred) - 6 months

Ambient - 4 hours

Refrigerated - 1 week

• CSF containing gadolinium-based contrast agents
• Hemolyzed or xanthochromic specimens

Quantitative spectrophotometry

0.0 - 2.5 U/L

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.

Angiotensin-converting enzyme catalyzes the formation of angiotensin II by cleaving the C-terminal histidylleucine dipeptide from angiotensin I. Indications are that ACE is affiliated with an autonomous renin-angiotensin system of the brain that participates in physiologic processes inside the brain. 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). Increased ACE concentrations in CSF are associated with neurosarcoidosis, with affected patients generally having activities approximately two-fold or more higher than those of healthy individuals. Increased CSF ACE has also been implicated in neurologic diseases, such as bacterial and viral meningitis and Behcet disease. Decreased concentrations have been reported in patients with Alzheimer disease, Parkinson disease, and progressive supranuclear palsy.