48-72 hours after setup at PeaceHealth Laboratories’ reference lab; next run if repeat testing is necessry.
Specimen Collection Details
One 7.5 mL serum separator tube (SST).
Allow to clot, centrifuge and separate serum from cells immediately.
Specimen stable 2 hours at ambient temperature, 7 days refrigerated, or 1 monthe frozen. Avoid repeated freeze/thaw cycles.
0.5 mL serum.
0.3 mL serum.
Plasma; severely lipemic, contaminated, or hemolyzed specimen.
≥ 0.5 nmol/L
Interpretive Data: Approximately 85-90% of patients with myasthenia gravis (MG) express antibodies to the acetylcholine receptor (AChR), which can be divided into binding, blocking, and modulating antibodies. Binding antibody can activate complement and lead to loss of AChR. Blocking antibody may impair binding of acetylcholine to the receptor, leading to poor muscle contraction. Modulating antibody causes receptor endocytosis resulting in loss of AChR expression, which correlates most closely with clinical severity of disease. Approximately 10-15% of individuals with confirmed myasthenia gravis have no measurable binding, blocking, or modulating antibodies.