Investigation in multiple sclerosis include:
- MRI scanning: 
- permits the visualisation of the dissemination of lesions in time and space
 - will reliably identify plaques in the cortex, brainstem and spinal cord
 - gadolinium enhancement improves sensitivity
 
 - CSF: 
- permits the detection of intrathecal inflammation
 - pleocytosis
 - slightly raised protein
 - 70% of patients hace a raised IgG - electrophoresis reveals oligoclonal bands in the CSF which are not found on serum electrophoresis
 
 - visual evoked potentials: 
- permit the demonstration of conduction changes consistent with demyelination
 - are of normal amplitude but show an increased latency in patients who have or have had optic neuritis
 - measurement of visual evoked potentials is a good way of demonstrating a previous, often subclinical, episode of demyelination in order to make the diagnosis of multiple sclerosis
 - auditory brainstem evoked potentials and somatosensory evoked potentials may also be measured
 
 
Before referring a person suspected of having MS to a neurologist, exclude alternative diagnoses by performing blood tests including (1):
- full blood count
 - inflammatory markers for example erythrocyte sedimentation rate, C-reactive protein
 - liver function tests
 - renal function tests
 - calcium
 - glucose
 - thyroid function tests
 - vitamin B12
 - HIV serology
 
Do not diagnose MS on the basis of MRI findings alone (1).
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