Acetylcholine Receptor (Muscle AChR) Binding Antibody, Serum
Use
The test is useful for supporting the diagnosis of autoimmune myasthenia gravis (MG) in adults and children. It helps distinguish autoimmune MG from congenital MG and other acquired forms of neuromuscular junction transmission disorders. It also serves as an adjunct to the test for P/Q-type calcium channel binding antibodies as a diagnostic aid for Lambert-Eaton myasthenic syndrome.
Special Instructions
Standalone testing is recommended in certain situations. This test should not be requested in patients who have recently received radioisotopes, as potential assay interference might occur. Specimens will be screened for radioactivity and held if necessary. It is advisable to collect specimens before initiating immunosuppressant medication for optimal antibody detection.
Limitations
The presence of elevated immunoglobulins due to therapeutic intervention may lead to false-positive results. Some patients with Lambert-Eaton syndrome, paraneoplastic disorders, and healthy individuals may present positive results. The presence of alpha-bungarotoxin antibodies may interfere with the assay. Specimens should ideally be collected before the initiation of immunosuppressive therapy as these may reduce test sensitivity.
New York Approved
Methodology
Immunoassay (RIA)
Biomarkers
LOINC Codes
- 97558-1
- 97558-1
Result Turnaround Time
3-6 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1.5 mL
Minimum Volume
1 mL
Container
Plastic vial
Collection Instructions
Collect serum in a preferred red top or acceptable serum gel tube.
Patient Preparation
For optimal antibody detection, collect specimen prior to initiation of immunosuppressant medication.
Storage Instructions
Refrigerated is preferred. Serum is stable for 28 days refrigerated, 72 hours ambient, or 28 days frozen.
Causes for Rejection
Gross hemolysis, lipemia, or icterus.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 28 days |
| Frozen | 28 days |