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Test ID: STR Striational (Striated Muscle) Antibodies, Serum

Reporting Name

Striational (Striated Muscle) Ab, S

Useful For

As a serological aid in the diagnosis of thymoma, especially in patients with onset of myasthenia gravis (MG) younger than 45 years


As a screening test for MG in older patients, especially when tests for muscle acetylcholine receptor (AChR) antibodies are negative


Serial measurements are useful in monitoring the efficacy of immunosuppressant treatment in patients with MG


Serial measurements are useful after treatment of thymoma


Serial measurements in recipients of D-penicillamine or bone marrow allografts may be useful in monitoring autoimmune complications and graft-versus-host disease, respectively

Specimen Type


Specimen Required


Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 1.5 mL

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  72 hours

Reference Values


Day(s) and Time(s) Performed

Monday through Friday; 4 a.m. and 3 p.m.

Saturday; 6 a.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
STR Striational (Striated Muscle) Ab, S 94817-4


Result ID Test Result Name Result LOINC Value
8746 Striational (Striated Muscle) Ab, S 94817-4

Clinical Information

Autoantibodies directed against the contractile elements of striated muscle are found in 30% of adult patients with myasthenia gravis and in 80% of those with thymoma. These antibodies may also be detected in patients with: Lambert-Eaton myasthenic syndrome, small-cell lung carcinoma, breast carcinoma, patients treated with D-penicillamine, bone marrow transplant recipients having graft-versus-host disease, and autoimmune liver disorders.


While this test is used as a serological aid in the diagnosis of thymoma, especially in patients with onset of myasthenia gravis (MG) younger than 45 years, it is more predictive of thymoma when accompanied by a muscle acetylcholine receptor (AChR) modulating antibody value of 90% or greater AChR loss and is most predictive of thymoma when accompanied by collapsin response-mediator protein-5-IgG (CRMP-5-IgG). Serial measurements are useful after treatment of thymoma. Measurements of muscle AChR binding, muscle AChR modulating antibody, and CRMP-5-IgG (if initially positive) are also recommended.


Striational antibodies occur in approximately:

-14% of patients with thymoma without clinical evidence of myasthenia gravis (MG)

-30% of patients with acquired (autoimmune) MG

-74% of patients with thymoma in association with MG

-25% of rheumatoid arthritis (RA) patients treated with D-penicillamine, 4% in untreated RA patients

-5% of patients with Lambert-Eaton myasthenic syndrome (LES) and/or small-cell lung carcinoma (SCLC) (MGL1 / Myasthenia Gravis [MG]/Lambert-Eaton Syndrome [LES] Evaluation and PAVAL / Paraneoplastic Autoantibody Evaluation, Serum)

-In some bone marrow recipients with graft-versus-host disease


The incidence in healthy subjects is under 1%.


A rising titer after removal of thymoma may be indicative of tumor recurrence.

Clinical Reference

1. Cikes N, Momoi MY, Williams CL, et al: Striational autoantibodies: quantitative detection by enzyme immunoassay in myasthenia gravis, thymoma, and recipients of D-penicillamine or allogeneic bone marrow. Mayo Clin Proc 1988 May;63(5):474-481

2. Lennon VA: Serological profile of myasthenia gravis and distinction from the Lambert-Eaton myasthenic syndrome. Neurology 1997;48(Suppl 5):S23-S27

3. Vernino S, Lennon VA: Muscle and neuronal autoantibody markers of thymoma: neurological correlations. Ann NY Acad Sci 2003 Sep;998:359-361

Analytic Time

3 days

Testing Algorithm

See Paraneoplastic Evaluation Algorithm in Special Instructions

Method Name

Enzyme Linked Immunosorbent Assay (ELISA)

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