Test ID: STR
Striational (Striated Muscle) Antibodies, Serum
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
This test is a useful 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 > or =90% AChR loss and is most predictive of thymoma when accompanied by CRMP-5-IgG.
It is useful as a screening test for MG in older patients, especially when tests for muscle 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. Measurements of muscle AChR binding, muscle AChR modulating antibody, and CRMP-5-IgG (if initially positive) are also recommended.
Serial measurements in recipients of D-penicillamine or bone marrow allografts may be useful in monitoring autoimmune complications and graft-versus-host disease, respectively.
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
See Paraneoplastic Evaluation Algorithm in Special Instructions.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
Enzyme Immunoassay (EIA)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Anti-Striated Antibody
Muscle (Skeletal) Antibodies
Myasthenia Gravis Antibodies
Myoid Antibody
Skeletal Muscle Antibodies
Striational (Striated Muscle) Antibodies
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Specimen Volume: 0.5 mL
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | Mild OK; Gross reject |
| Icterus | Mild OK; Gross reject |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 14 days |
| Ambient | 72 hours | |
| Frozen | ||
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
<1:60
Interpretation Provides information to assist in interpretation of the test results
Autoantibodies reactive with contractile elements of skeletal muscle are detectable in sera of approximately 30% of patients with acquired (autoimmune) myasthenia gravis (MG) and 74% of patients with thymoma in association with MG.
Striational antibodies occur also in approximately:
-14% of patients with thymoma without clinical evidence of 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) (MGLES/83369 Myasthenia Gravis [MG]/Lambert-Eaton Syndrome [LES] Evaluation and PAVAL/83380 Paraneoplastic Autoantibody Evaluation, Serum)
-In some bone marrow recipients with graft-versus-host disease
The incidence in healthy subjects is <1%.
A rising titer after removal of thymoma may be indicative of tumor recurrence.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
A negative result does not exclude the presence of thymoma (20% are negative).
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
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
Method Description Describes how the test is performed and provides a method-specific reference
Protein antigens extracted from adult rat skeletal muscle in 600 mM KCl are applied to wells of an enzyme-linked immunosorbent assay (ELISA) plate. Serially diluted patient's serum is added. After washing, alkaline phosphatase conjugated antibodies to human IgG, IgM, and IgA are added, washing is repeated, and then the enzyme substrate is added. Results are expressed as antibody titer, ie, the greatest dilution at which the optical density of the reaction product is >1.50 x the mean value of 4 normal control sera. (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;63:474-481)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Thursday, Sunday; 10:30 p.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
83520
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 8746 | Striational (Striated Muscle) Ab, S | 8097-8 |
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