Authored by MCN Neurologists
To ensure an accurate diagnosis, it is common practice to perform a thorough battery of diagnostic investigations when evaluating a patient for multiple sclerosis (MS). Multiple sclerosis is, however, ultimately a clinical diagnosis, because there are no definite laboratory tests.
Blood tests are used to exclude appropriate alternative diagnoses or co-diagnoses. They include a search for antinuclear antibodies, to rule out collagen vascular diseases and vasculitis. As well, your doctor may do checks for thyroid disorders, Lyme`s disease, vitamin B12 and folate deficiencies and tropical infections with HTLV-1 virus. Occasionally, your doctor may do additional tests to look for sarcoidosis, adrenoluekodystrophy and myasthenia gravis.
Magnetic resonance imaging (MRI) and cerebro-spinal fluid (CSF) analysis are two main laboratory tests for MS. MRI of the brain and spinal cord may show the presence of lesions with certain characteristics that may be compatible with a diagnosis of MS. Presence of multiple lesions in the brain and/or spinal cord, with or without contrast enhancement of the MRI, may point to evidence of MS, its activity and severity, as well as progressions of the disease.
Compared with MRI, CSF analysis is somewhat invasive and, therefore, is not used as often to establish the diagnosis of MS. CSF analysis is especially helpful, though, when there is a presence of atypical features on a patient’s history and examination, as well as non-conclusive MRI data. Oligoclonal bands are the most specific for MS, although there is a possibility of false-positive results. CSF cell count, protein, glucose, VDRL titer, myelin basic protein and intrathecal IgG production are also important parameters in ruling out other disorders that can mimic MS. CSF studies, therefore, are used not only to support the diagnosis of MS, but also to suggest a misdiagnosis.
Visual evoked potential tests (VEP) are used to document lesions within visual pathways or the brain stem. The presence of abnormalities on VEP testing may support evidence of disseminated disease, which is likely in cases of MS.
In certain circumstances, a number of other diagnostic procedures may be indicated. Additional ancillary laboratory tests may include urodynamics, to document neurogenic bladder, neurocognitive testing, to document cognitive abnormalities, and electrophysiological tests, to rule out peripheral neuropathy.
For further information about Multiple Sclerosis, click on the following links:
Multiple Sclerosis Treatment and Research Center
Schapiro Center for Multiple Sclerosis
South Metro Muliple Sclerosis Center
http://www.nationalmssociety.org/chapters/MNM/index.aspx (National Multiple Sclerosis Society, Minnesota Chapter)
January 1, 2010
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