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For hours, walk-ins and appointments.Acetylcholine Receptor (AChR)-modulating Antibodies, Flow Cytometry
CPT:
86043
Expected Turnaround Time
5 - 7 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Documents
Specimen Requirements
Specimen
Serum
Volume
0.5 mL
Minimum Volume
0.3 mL (Note: This volume does not allow for repeat testing.)
Container
Serum from a red-top tube; serum from a gel tube
Storage Instructions
Room temperature
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Causes for Rejection
Improper labeling; gross microbial contamination; specimen contaminated with anticoagulants; chyous serum; plasma specimen; excessive hemolysis
Test Details
Use
Diagnose myasthenia gravis (MG); monitor response to treatment of myasthenia gravis
Limitations
In rare cases AChR antibodies can be found in patients with other autoimmune disorders or with thymoma without Myasthenia Gravis (MG).
The causative autoantibody cannot be identified in up to 10% of patients with MG.
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Methodology
Flow Cytometry
Additional Information
The majority of patients with MG have antibodies to the acetylcholine receptor (AChR) and, less frequently, to other proteins at the postsynaptic membrane of the neuromuscular junction. AChR antibodies impede neuromuscular transmission by a range of pathogenic mechanisms including the alteration of tissue architecture and/or by causing a reduction of the density or functionality of AChRs. Three functionally different types of antibodies against muscle AChR can be measured.
AChR modulating antibodies crosslink receptor subunits in such a way as to cause the receptors to be internalized and degraded in a process known as antigenic modulation. Modulating antibodies are implicated with an increased risk of thymoma and the majority of patients with thymoma and MG have modulating antibodies.
References
Bernard C, Frih H, Pasquet F, et al. Thymoma associated with autoimmune diseases: 85 cases and literature review. Autoimmun Rev. 2016 Jan;15(1):82-92.26408958
Berrih-Aknin S, Le Panse R. Myasthenia gravis: a comprehensive review of immune dysregulation and ethiological mechanisms. J Autoimmun. 2014 Aug;52:90-100.24389034
Gilhus NE. Myasthenia Gravis Can Have Consequences for Pregnancy and the Developing Child. Front Neurol. 2020 Jun 12;11:554.32595594
Gilhus NE, Skeie GO, Romi F, Lazaridis K, Zisimopoulou P, Tzartos S. Myasthenia gravis - autoantibody characteristics and their implications for therapy. Nat Rev Neurol. 2016 May;12(5):259-268.27103470
Hehir MK, Silvestri NJ. Generalized Myasthenia Gravis: Classification, Clinical Presentation, Natural History, and Epidemiology. Neurol Clin. 2018 May;36(2):253-260.29655448
Juel VC, Massey JM. Myasthenia gravis. Orphanet J Rare Dis. 2007 Nov 6;2:44.17986328
Phillips WD, Vincent A. Pathogenesis of myasthenia gravis: update on disease types, models, and mechanisms. F1000Res. 2016 Jun 27;5:F1000 Faculty Rev-1513.27408701
Randomized Trial of Thymectomy in Myasthenia Gravis [published erratum]. N Engl J Med. 2017 May 25;376(21):2097.28471717
Skeie GO, Apostolski S, Evoli A, et al. Guidelines for treatment of autoimmune neuromuscular transmission disorders. Eur J Neurol. 2010 Jul;17(7):893-902.20402760
Verschuuren JJ, Huijbers MG, Plomp JJ, et al. Pathophysiology of myasthenia gravis with antibodies to the acetylcholine receptor, muscle-specific kinase and low-density lipoprotein receptor-related protein 4. Autoimmun Rev. 2013 Jul;12(9):918-923.23535160
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 505225 | AChR-modulating Ab | 99062-2 | 505199 | AChR-modulating Ab | % | 99062-2 |
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