Sulfate Glucurony Paragloboside (SGPG) antibody; IGM

Category: Neuroimmunology
Test Code: 464
Disease: Neuropathies
Methodology: ELISA
Reference Range: Negative: <1 ; Positive: >1
CPT Code: 83516
Schedule / Turnaround Time: Assay performed every three weeks. Report availability is within three weeks from the time of specimen receipt.
Specimen Requirements:

Specimen need not be refrigerated or frozen. Collect 2-3 ml of blood in a red top or serum separator tube. If possible, separate serum from clot and place into white tube provided with Immco Diagnostics’ collection kits. If separation facilities are not available, the blood can be sent in the tube used for collection.

Sample Stability:

Sample is stable at ambient temperature during shipment. If sample is stored prior to shipment, it is stable at refrigerated (2-8°C) up to five days and frozen (-20°C) up to a year.


Autoantibodies against MAG or SGPG in peripheral neuropathies with monoclonal IgM gammopathies occur in about 50% of patients. The presence of the reactive epitope on MAG led to the discovery of peripheral nerve acidic glycolipid SGPG.The detection of MAG IgM antibodies is useful as it suggests the presence of active demyelination in peripheral neuropathy. Neuropathies associated with anti-MAG are often slowly progressive with evidence of demyelination and a variable degree of axonal loss associated with gait ataxia. 50% of all peripheral neuropathy cases with IgM paraproteinemia possess MAG antibodies. Majority of the MAG-positive patients will also be positive for SGPG because of the sharing of the common epitope between them. SGPG positive cases in the absence of MAG IgM antibodies suggest a multi-focal motor neuropathy with conduction blocked.