INTENDED USE

The AChRAb Assay is a radioimmunoassay for the in-vitro-diagnostic semi-quantitative determination of autoantibodies against the acetylcholine receptor in human serum. The AChRAb assay is useful as an aid in the differential diagnosis of Myasthenia Gravis (MG) in conjunction with other clinical and laboratory findings.

SUMMARY AND EXPLANATION

Myasthenia Gravis (MG) is a skeletal muscle disorder characterized by muscular weakness. A good correlation is observed between anti-acetylcholine receptor (AChR) antibodies and muscle weakness in individual patients. Anti-AChR antibodies are present in approximately 90% of patients with MG. Anti-AChR antibodies could be: binding antibodies (multitudes of wide populations of antibodies directed to hydrophilic domains of receptors), blocking antibodies (preventing binding of acetylcholine to receptors) and modulating antibodies (accelerating endocytosis resulting in loss of receptors).

TEST PRINCIPLE

Anti-AChR antibodies are detectable by a radiobinding that is followed by precipitation of the antibodies. Patient specimens and references are incubated with detergent-solubilized fetal and adult AChRs labeled with ¹²⁵I-?-bungarotoxin. The resulting bound complexes of labeled AChRs and autoantibodies are then immunoprecipitated with anti-human IgG. After centrifugation, the supernatant is aspirated and the pellet containing labeled AChR/autoantibody-bound complexes is counted in a gamma counter. Counts are directly proportional to the amount of autoantibodies present.

Catalog Number	ACRB4000-30/120
Tests per Kit	30/120
Method	RIA
Incubation Time	2 hours, 3 x 30 minutes