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Test Code CCPQ P/Q-Type Calcium Channel Antibody, Serum


Ordering Guidance


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.



Specimen Required


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


Useful For

Confirming a diagnosis of Lambert-Eaton syndrome

 

Implicating autoimmunity as a disease-causing 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.

Method Name

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)

Specimen Type

Serum

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

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

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Reference Values

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

 

≤0.02 nmol/L

Interpretation

Values greater than 0.02 nmol/L are consistent with neurologic autoimmunity and suggest a paraneoplastic basis.

 

Values in nonimmunosuppressed patients with Lambert-Eaton syndrome are usually greater than 0.1 nmol/L.

Method Description

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-labeled omega-conopeptide-MVIIC. After incubating patient sample with labeled receptors, anti-human IgG is added to form an immunoprecipitate. The amount of (125)I-labeled receptors in the immunoprecipitate is measured using a gamma-counter. The amount of gamma emission in the precipitate is proportional to the amount of CCPQ-IgG in the sample. Results are reported as units of precipitated antigen (nMol) per L of patient sample.(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;72[11]:1304-1312 doi:10.1001/jamaneurol.2015.2378)

Day(s) Performed

Monday through Sunday

Report Available

3 to 7 days

Specimen Retention Time

28 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

86596

LOINC Code Information

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
81185 P/Q-Type Calcium Channel Ab 94349-8

Secondary ID

81185