Musk Quantitative Titres Antibody Test

Muscle-Specific Receptor Tyrosine Kinase (MuSK) Antibody is a diagnostic testing process for patients with generalized or ocular myasthenia gravis. MuSK antibodies are detected in patients who are seronegative for Acetylcholine receptor antibodies. A blood sample is taken to measure the level of Anti MuSK Antibodies in the blood. The test is done to confirm Myasthenia Gravis and also during and after the treatment of Myasthenia Gravis. A characteristic of Myasthenia Gravis is that the patient tends to experience weakness that comes on with activity which improves following taking rest. Symptoms may show Bulbar weakness, diplopia, dysarthria, difficulty in chewing or swallowing.

More than one-third of people who are seronegative for muscle AChR antibody can suffer from Muscle-specific kinase (MuSK) antibody. No special preparations needed as the test requires only a blood sample. Since MG patients tend to experience weakness, they are requested to lie down when giving the blood test. Serum samples need to be shipped frozen, refrigerated. The samples sent at room temperature and must be received within 48 hours of collection.

It is important to perform a comprehensive serological evaluation before initiating immunosuppressive therapy. When characteristic signs of myasthenia gravis are eclipsed by superimposition of a steroid-induced myopathy, the interpretation of the patient’s serological and clinical status becomes a bit difficult.

The test is useful for diagnosis of an autoimmune muscle-specific kinase (MuSK) myasthenia gravis. When first-line serologic tests are negative, it aids in the diagnosis of MuSK. It allows doctors to draw a quantitative baseline for MuSK antibodies and to compare with future levels, if weakness is worsened over time. Females are more commonly affected by autoimmune MuSK MG as compared to males. This test may also reveal antinuclear antibodies, glutamic acid, and decarboxylase (GAD65) antibodies. MG is characterized by muscle weakness and fatigability, affecting mainly ocular muscles in AChR MG. MG with anti-MuSK antibodies is a specific subgroup of seronegative MG.

A clinician may ask you to lie down before drawing blood from your veins. Blood is drawn from a vein by piercing a needle into the vein. About 2 mL (0.5 mL minimum) blood serum is collected in a Red-top tube or Serum Separator Tube (SST). The serum is separated from the whole blood in less than 72 hours from drawing it. When collecting the sample, label each specimen tube with two forms of patient identification. This must also appear on the requisition form. The serum sample is then refrigerated and readied for transport. The serum stays stable at room temperature for up to three days.