Confirming a diagnosis of Lambert-Eaton syndrome
Implicating autoimmunity as a pathogenic mechanism in patients with complex neurologic presentations, particularly in those with a history of cancer
Implicating autoimmunity as the basis of limbic encephalitis, cerebellar ataxia, myelopathy, peripheral neuropathy, or autonomic neuropathy
This test is not useful as a general screening test for cancer.
Only orderable as part of a profile. For more information see:
PAVAL / Paraneoplastic, Autoantibody Evaluation, Serum
MGLE / Myasthenia Gravis/Lambert-Eaton Myasthenic Syndrome Evaluation, Serum
MDS2 / Movement Disorder, Autoimmune Evaluation, Serum
PNEFS / Neuroimmunology Antibody Follow-Up, Serum
Radioimmunoassay (RIA)
Calcium Channel Blockers
Conotoxin (Receptor) Antibodies
Lambert-Eaton Myasthenic Syndrome Ab
LEMS Antibodies
Motor Nerve Terminal Antibodies
P/Q Type Calcium Channel Antibody, Serum
P/Q-Type Calcium Channel
Paraneoplastic Autoantibody Comprehensive Panel, Serum
Paraneoplastic Autoantibody Lung/Thymoma Panel, Serum
Voltage-Gated Calcium Channel Ab
Serum
The profile test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. The specific waiting period before specimen collection will depend on the isotope administered, the dose given and the clearance rate in the individual patient. Specimens will be screened for radioactivity prior to analysis. Radioactive samples received in the laboratory will be held 1 week and assayed if sufficiently decayed or canceled if radioactivity remains.
Only orderable as part of a profile. For more information see:
PAVAL / Paraneoplastic, Autoantibody Evaluation, Serum
MGLE / Myasthenia Gravis/Lambert-Eaton Myasthenic Syndrome Evaluation, Serum
MDS2 / Movement Disorder, Autoimmune Evaluation, Serum
PNEFS / Neuroimmunology Antibody Follow-Up, Serum
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 4 mL
0.5 mL
Gross hemolysis | Reject |
Gross lipemia | Reject |
Gross icterus | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 28 days | |
Frozen | 28 days | ||
Ambient | 72 hours |
Confirming a diagnosis of Lambert-Eaton syndrome
Implicating autoimmunity as a pathogenic mechanism in patients with complex neurologic presentations, particularly in those with a history of cancer
Implicating autoimmunity as the basis of limbic encephalitis, cerebellar ataxia, myelopathy, peripheral neuropathy, or autonomic neuropathy
This test is not useful as a general screening test for cancer.
This test is not offered as a free-standing test but is included in the following test procedures as an aid for diagnosis of neurological autoimmunity, usually in a paraneoplastic context.
P/Q-type calcium channels regulate neurotransmitter release at motor nerve terminals and are involved in central neurotransmission.
A snail venom toxin, omega conopeptide MVIIC, is a specific high-affinity antagonist for P/Q-type channels.
Autoantibodies directed against extracellular epitopes of P/Q-type calcium channels are implicated as the effectors of the Lambert-Eaton myasthenic syndrome (LES).
These antibodies generally reflect an immune response against cancer.
P/Q-type calcium channel binding antibodies are found in 95% of non-immunosuppressed patients with LES (100% of those with cancer) and in 20% of patients who have encephalomyeloneuropathies related to carcinoma of lung, breast, or ovary.
Only orderable as part of a profile. For more information see:
PAVAL / Paraneoplastic, Autoantibody Evaluation, Serum
MGLE / Myasthenia Gravis/Lambert-Eaton Myasthenic Syndrome Evaluation, Serum
MDS2 / Movement Disorder, Autoimmune Evaluation, Serum
PNEFS / Neuroimmunology Antibody Follow-Up, Serum
< or =0.02 nmol/L
Values greater than 0.02 nmol/L are consistent with neurologic autoimmunity and suggest a paraneoplastic basis.
Values in non-immunosuppressed patients with Lambert-Eaton syndrome are usually greater than 0.1 nmol/L.
High-dose intravenous IgG therapy may cause false-lowering of (or negative) values.
Plasma specimens can yield false-positive results.
The influence of myeloma M proteins is uncertain.
1. Lennon VA, Kryzer TJ, Griesmann GE, et al: Calcium-channel antibodies in the Lambert-Eaton myasthenic syndrome and other paraneoplastic syndromes. N Engl J Med. 1995;332:1467-1474
2. Lennon VA: Serological profile of myasthenia gravis and distinction from the Lambert-Eaton myasthenic syndrome. Neurology. 1997;48(Suppl 5):S23-S27
3. Zalewski NL, Lennon VA, Lachance DH, Klein CJ, Pittock SJ, Mckeon A: P/Q- and N-type calcium-channel antibodies: Oncological, neurological, and serological accompaniments. Muscle Nerve. 2016 Aug;54(2):220-227. doi: 10.1002/mus.25027
High voltage-activated calcium channels of P/Q-type (ie, high affinity receptors for omega-peptide MVIIC) are solubilized from porcine cerebral cortical membranes in detergent and are complexed with (125)I-labelled omega-conopeptide-MVIIC. After adding a patient's serum and antihuman IgG and IgM to form an immunoprecipitate, specific antibodies are detected by counting gamma-emission from the (125)I-omega-peptide that coprecipitates with any P/Q-type calcium channels that have bound antibodies.(Griesmann GE, Kryzer, TJ, Lennon VA: Autoantibody profiles of myasthenia gravis and Lambert-Eaton myasthenic syndrome. In: Rose NR, Hamilton RG, Detrick B, eds. Manual of Clinical and Laboratory Immunology. 6th ed. ASM Press; 2002:1005-1012; Jones AL, Flanagan EP, Pittock SJ, et al: Responses to and outcomes of treatment of autoimmune cerebellar ataxia in adults. JAMA Neurol. 2015 Nov;72[11]:1304-1312 doi: 10.1001/jamaneurol.2015.2378)
Monday through Sunday
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 US Food and Drug Administration.
86596
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
CCPQ | P/Q-Type Calcium Channel Ab | 94349-8 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
81185 | P/Q-Type Calcium Channel Ab | 94349-8 |