MUSKab ELISA Kit (Muscle Skeletal Receptor Tyrosine Kinase Antibody)

Full Name: MUSKab ELISA Kit (Muscle Skeletal Receptor Tyrosine Kinase Antibody)
Reactivity: Human
Sample Type: Plasma, Tissue Homogenates, Serum, Biological Fluids
Sensitivity: 1.406 ng/ml


MUSKab stands for muscle skeletal receptor tyrosine-protein kinase antibody. It is a receptor found in the neuromuscular junction and MUSKabs are autoantibodies directed against the receptor. Measurement of MUSKab helps diagnose myasthenia gravis and distinguishes it from other neurological disorders.

Myasthenia gravis is an autoimmune disorder where antibodies block or destroy nicotinic acetylcholine receptors on the postsynaptic muscle membrane. This disrupts signaling at the neuromuscular junction, leading to muscle weakness and fatigability. Around 15% of myasthenia cases involve autoantibodies against other neuromuscular proteins like MUSK instead of the acetylcholine receptor. MUSK helps organize the neuromuscular junction, so MUSKabs interfere with signaling between motor neurons and muscle fibers.

Testing blood for MUSKabs aids myasthenia diagnosis, especially in seronegative patients with no detectable acetylcholine receptor antibodies. Presence of MUSKabs confirms an autoimmune basis for symptoms like fluctuating skeletal muscle weakness. MUSKab titer levels may also correlate with disease severity and treatment response monitoring needs. However, MUSKabs differ from acetylcholine receptor antibodies in some clinical aspects. Patients with MUSKab-associated myasthenia gravis can experience more focal muscle involvement, predominance in facial and tongue muscles, and graver disease severity.


Human MUSKab ELISA kit can measure concentrations of muscle skeletal receptor tyrosine kinase antibody (MUSKab) present is plasma, serum, biological fluids or tissue homogenate samples.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • One 96-Well Plate: Pre-coated with anti- MUSKab.
  • Standards: Lyophilized recombinant.
  • Sample/Standard Dilution Buffer.
  • Biotinylated-labelled Antibody.
  • Antibody Dilution Buffer.
  • HRP-Streptavidin Conjugate (SABC).
  • SABC Dilution Buffer.
  • TMB Substrate.
  • Wash Buffer (25x).
  • Plate Sealer.
  • Product Instructions.


For this MUSKab ELISA kit, it is recommended that a standard curve is generated for each assay carried out.

Standard Curve: 0, 2.344, 4.688, 9.375, 16.75, 37.5, 75, 150 ng/ml.
Reactivity: Human
Sensitivity: 1.406 ng/ml
Range: 2.344 – 150 ng/ml
Principle: Sandwich, Double Antibody
Application: Research Use Only.


– Specificity: Highly specific for MUSKab, no cross reactivity or interference between MUSKab and analogues was detected.
– Recovery: Serum (87 – 105%), EDTA Plasma (89 – 103%), Heparin Plasma (87 – 104%).
– Linearity: Serum (89 – 103%), EDTA Plasma (96 – 101%), Heparin Plasma (82 – 98%).
– Precison Intra-Assay: CV < 8%
– Precison Inter-Assay: CV < 10%


  1. MuSK antibody clearance during serial sessions of plasmapheresis for myasthenia gravis. J Neurol Sci. (2007) 263 (1-2): 191-3. Yeh J.H., et al.
  2. Afterdischarges in Myasthenia Gravis. Front Neurol. (2021) 12: 599744. Yang L., et al.
  3. Muscle-Specific Tyrosine Kinase-Associated Myasthenia Gravis: A Neuromuscular Surprise. Case Rep Neurol Med. (2021) 2021: 1326442. Ali H., et al.


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