In addition to those laboratory tests normally required for monitoring patients with multiple sclerosis, complete blood and differential white blood cell counts, platelet counts, and blood chemistries, including liver function tests (e. g. aspartate aminotransferase serum glutamic-oxaloacetic transaminase (SGOT), alanine aminotransferase serum glutamate pyruvate transaminase (SGPT) and gamma glutamyltransferase), are recommended prior to initiation and at regular intervals following introduction of Extavia therapy, and then periodically thereafter in the absence of clinical symptoms.