Imperial Collage Healthcare

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CSF Angiotensin Converting Enzyme (CSF ACE)

Lab Code : CSF (ACE)

Test Background

Diagnosis is of neurosarcoidosis (NS) is notoriously difficult and usually relies on the exclusion of other causes. NS usually only develops in patients with significant systemic sarcoidosis, however some patients may develop NS prior to being diagnosed with sarcoidosis. As a result patient workup can be challenging. Angiotensin converting enzyme in cerebrospinal fluid (CSF ACE) has been reported to be a potentially useful biomarker in aiding the diagnosis of NS. Although non-specific, CSF ACE is thought to be increased in approximately 50% of all NS patients.

Clinical Indications

NS usually only develops in patients with significant systemic sarcoidosis. It is thought that approximately 5 – 15% of sarcoidosis patients may develop NS, but around half of these individual are subclinical. Symptoms may include: headaches, visual, ataxia, vomiting, cranial neuropathy (presenting feature in ~50% cases). 

Reference Range

Normal Range                      ≤ 2.0 U/L

Borderline High Results       1.5 – 2.0 U/L

High Results                        > 2.0 U/L

Sample Required
CSF in universal container samples (EDTA and Fluoride interfere with the assay and are unsuitable).

Sample Volume
300 µL (500 µL preferred)


It is recommended that all samples are promptly stored at 4°C and where possible frozen at -20°C. 

Turnaround Time

4 weeks


Patients on ACE inhibitors may produce significantly lower results (often below the limit of detection).  

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