Neuromyelitis opticus (NMO), also known as Devic’s disease, is an inflammatory disease of the central nervous system characterized by severe optic neuritis and transverse myelitis, usually with a relapsing-remitting disease course. The analysis of anti-aquaporin-4 (AQP4) antibodies (also known as NMO-IgG) identifies circulating autoantibodies against aquaporin-4, a water channel molecule expressed on astrocytes in the central nervous system. AQP4 antibodies can be detected in serum from approximately 75% of patients with NMO, and can be identified in patients with isolated, longitudinally extensive transverse myelitis or optic neuritis (NMO spectrum disease).
The result of the analysis is given as units/mL (U/ml), which is calculated from the amount of antibodies to aquaporin-4 in a dilution of the sample using an ELISA-kit from DLD Diagnostika, Germany. The number of U/ml is proportional to the amount of anti-aquaporin-4 in the sample.
The results should be interpreted as follows:
<3 U/ml: negative for anti-aquaporin-4 antibodies
>=3 U/ml: positive for anti-aquaporin-4 antibodies
The analysis is performed in Neuroimmunology Laboratory once a week. Since all positively screened samples are sent to Odense University Hospital, DK, for confirmation by a cell-based analysis, longer response times are expected. The OUH-analysis does not give a titer, thus the titer given are from the preliminary ELISA analysis.
The result of the analysis is sent to LABKAII/sundhedsplatform for hospitals in Region H.