From the Guidelines
For a patient with optic neuritis, I would order anti-aquaporin-4 (AQP4) antibodies and anti-myelin oligodendrocyte glycoprotein (MOG) antibodies as the most important initial tests to identify potential underlying causes, particularly to differentiate between neuromyelitis optica spectrum disorder (NMOSD) and MOG antibody-associated disease.
Key Laboratory Tests
- Anti-aquaporin-4 (AQP4) antibodies for NMOSD diagnosis 1
- Anti-myelin oligodendrocyte glycoprotein (MOG) antibodies for MOG antibody-associated disease diagnosis 1
- Antinuclear antibodies (ANA), anti-double-stranded DNA, anti-SSA/SSB antibodies for autoimmune conditions like lupus and Sjögren's syndrome 1
- Angiotensin-converting enzyme (ACE) levels for sarcoidosis
- Complete blood count, comprehensive metabolic panel, erythrocyte sedimentation rate, and C-reactive protein to assess for systemic inflammation
- Vitamin B12 and folate levels to rule out nutritional deficiencies
- Infectious disease testing including syphilis serology (RPR/VDRL), Lyme disease antibodies, and tuberculosis testing (QuantiFERON-TB Gold) 1
Rationale
Optic neuritis can be the presenting symptom of multiple systemic conditions, and identifying the underlying cause is crucial for guiding appropriate treatment. Early diagnosis of conditions like NMOSD is particularly important as they require different treatment approaches than typical demyelinating optic neuritis associated with multiple sclerosis. The presence of AQP4 or MOG antibodies can significantly influence the treatment strategy and prognosis.
Additional Considerations
- MRI of the orbits and brain to evaluate for abnormal enhancement and signal changes within the optic nerve and to assess for associated intracranial demyelinating lesions 1
- CSF analysis for oligoclonal bands and to assess for intrathecal antibody production 1
- Monitoring of MOG-IgG titers may be useful in some cases to predict relapse or to monitor treatment response, although its utility is still being defined 1
From the Research
Lab Tests for Optic Neuritis
To diagnose optic neuritis, several lab tests can be ordered, especially antibody tests. The following are some of the key tests:
- Visual acuity test
- Humphrey and/or Goldmann visual field test
- Non-mydriatic fundus photography
- Optic disc OCT
- 3 Tesla orbital-cerebral MRI with and without contrast
- Standard and immunological laboratory testing for anti-MOG and anti-AQP4 antibodies by Western Blot and ELISA 2
Antibody Tests
Specific antibody tests that can be ordered for optic neuritis include:
- Anti-MOG antibodies: These antibodies are associated with optic neuritis, especially in patients with a history of demyelinating neurological manifestations 2, 3
- Anti-AQP4 antibodies: These antibodies are associated with neuromyelitis optica spectrum disorders and can also be present in patients with optic neuritis 4, 5
Clinical Implications
The results of these lab tests can have significant clinical implications, including: