In 2006, revised diagnostic criteria were proposed by Dean Wingerchuk, MD, MSc. These guidelines include two absolute criteria, as well as the need for fulfillment of at least 2 out of 3 supportive criteria in order to be diagnosed with NMO. These criteria are as follows:
- Optic neuritis
- Brain MRI not meeting criteria for MS diagnosis
- Positive NMO-IgG test
- LETM on T2-weighted imaging on MRI
Sometimes, if one does not meet these criteria, a diagnosis of NMO spectrum disorder is given at the discretion of the practitioner, because of the pattern and severity of their attacks, response to immunomodulatory agents, MRI evidence, or the high specificity of the NMO-IgG. An NMO spectrum diagnosis is highly likely to become clinically definite NMO. Regardless of the diagnosis of clinical definite NMO or NMO spectrum disorder, the standard of care for acute and maintenance therapy is the same.