Specimen Requirements


Voltage Gated Calcium Channel Type N AB

Specimen Requirement

Collect SST/1.0 mL serum, after 30 minutes of clotting, promptly centrifuge and send.


Radioimmunoassay (RIA)


Room temp: 48 hours, Refrigerated: 48 hours, Frozen: 60 days

Reference Range

Reference ranges are determined by the performing laboratory and will show on the report.


7-14 days Performed Tuesday, Thursday

Clinical Use

N-type calcium channel antibodies are more highly associated with primary lung cancer than P/Q-type. One or all of the autoantibodies in the myasthenia gravis (MG)/LEMS evaluation can occur with neoplasia without evidence of neurological impairment. One or both calcium channel antibodies (P/Q and N) can occur with paraneoplastic and idiopathic cerebellar ataxia, encephalomyeloneuropathies, and autonomic neuropathy. Classical symptoms of LEMS include proximal muscle weakness, fatigability, dry mouth and impotence. When presentation is further complicated with oculobulbar weakness, these symptoms can easily be misinterpreted as MG. However, because VGCC antibodies are positive in only approximately 5% of MG patients, the measurement of these antibodies is very useful in distinguishing LEMS from MG.

Test Code