Table 3.

Guidelines on the use of anti-interferon β (IFN-β) antibody testing in multiple sclerosis

Recommendations by the European Federation of Neurological Societies (EFNS)	Level of recommendation
BAb assays can be used for screening of IFN-β antibodies	Level A
NAb testing should be performed in specialized laboratories	Level A
Nab should be performed with validated CPE or MxA assays using serial dilution test	Level A
NAb should be tested within first 24 months of therapy	Level A
NAb measurement is not needed in NAb patients after 24 months of IFN therapy	Level B
Patients with NAb should be retested every 3–6 months	Level A
Therapy should be discontinued in patients with high titer NAbs and retested in 3–6 months	Level A

Data modified from Sorensen et al. (2005a).

BAb, Binding antibodies; Nab, neutralizing antibodies; CPE, cytopathic effect; MxA, myxovirus resistance protein 1.