Bottom line: In CSF analysis, a finding of elevated ACE is highly specific but not very sensitive for diagnosis of neurosarcoidosis.
Summary: Neurosarcoidosis>CSF Analysis. In: DynaMed. Provides an overview of CSF findings to consider in diagnosing neurosarcoidosis, including elevated proteins, decreased glucose, and increased angiotensis converting enzyme (ACE).
CSF may be abnormal in 80% of patients with neurosarcoidosis and CSF ACE may be elevated in patients with neurosarcoidosis, but it has not been shown to be specific.
Khoury J, et al. Cerebrospinal fluid angiotensin-converting enzyme for diagnosis of central nervous system sarcoidosis. The Neurologist. 2009; 15(2):108-111.
A structured review of papers reporting on sensitivity and specificity of CSF ACE in diagnosing neurosarcoidosis. Included papers where all patients received both CSF ACE and tissue biopsy. RESULTS: Two retrospective series were included. In one study, 11 patients had neurosarcoidosis, 87 had other neurological diseases and 120 had diagnosis not reported in the paper. Sensitivity was 54.5% (95% CI, 25.1-84.0) and specificity was 93.7% (95% CI, 90.4-97.0). In the second study, 9 patients had neurosarcoidosis and 101 did not. Sensitivity was 23.5% (95% CI, 3.4-43.7) and specificity was 94.6 (95% CI, 90.0-99.2). These studies showed low sensitivity and high specificity, but studies had methodological limitations. Patients were referred to hospital for testing for suspected neurosarcoidosis. ACE levels are known to be elevated in other conditions, such as malignancy and infection (Pract Neurol 2007; 7: 234–244)