Paraneoplastic Autoantibody Evaluation, Serum (Sendout)

Useful For:

• Serological evaluation of patients who present with a subacute neurological disorder of undetermined etiology, especially those with known risk factors for cancer
• Directing a focused search for cancer
• Investigating neurological symptoms that appear in the course of, or after, cancer therapy, and are not explainable by metastasis
• Differentiating autoimmune neuropathies from neurotoxic effects of chemotherapy
• Monitoring the immune response of seropositive patients in the course of cancer therapy
• Detecting early evidence of cancer recurrence in previously seropositive patients
• For a complete list of tests and potential reflex tests included in this panel, refer to the Mayo Paraneoplastic Evaluation Algorithm - Serum.

Ordering Guidance: The Paraneoplastic Autoantibody Evaluation is not the recommended test for patients suspected of autoimmune neurological disorders. A comprehensive neurological phenotype-specific autoimmune/paraneoplastic evaluation (e.g. encephalopathy, movement disorders, myelopathy, axonal neuropathy, etc.) should be considered. For additional guidance, review the Autoimmune Encephalitis Testing Recommendations or consult the Laboratory Medicine Resident on-call.

Individual Antibody Follow-Up Testing: Individual antibody tests within the Paraneoplastic Autoantibody Evaluation are available for patients who have previously tested positive for those antibodies within the past five years at a Mayo laboratory. Refer to Mayo test: Neuroimmunology Antibody Follow-up, Serum.

Reference Values:

Note: Includes reference values for panel tests only.

Neuron-restricted patterns of IgG staining that do not fulfill criteria for amphiphysin, ANNA-1, ANNA-2, ANNA-3, AGNA-1, PCA-1, PCA-2, PCA-Tr, or CRMP-5-IgG may be reported as "unclassified antineuronal IgG." Complex patterns that include non-neuronal elements may be reported as "uninterpretable."

CRMP-5 Note: CRMP-5 titers lower than 1:240 are detectable by recombinant CRMP-5 Western blot analysis. CRMP-5 Western blot analysis will be done on request on stored serum (held 4 weeks). This supplemental testing is recommended in cases of chorea, vision loss, cranial neuropathy, and myelopathy.

Interpretation: Antibodies directed at onconeural proteins shared by neurons, glia, muscle, and certain cancers are valuable serological markers of a patient's immune response to cancer. They are not found in healthy subjects and are usually accompanied by subacute neurological symptoms and signs. Several autoantibodies have a syndromic association, but no autoantibody predicts a specific neurological syndrome. Conversely, a positive autoantibody profile has 80% to 90% predictive value for a specific cancer. It is not uncommon for more than one paraneoplastic autoantibody to be detected, each predictive of the same cancer.

Outside Laboratories: Centrifuge sample and transfer serum into a separate plastic vial. Refrigerate serum.

Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.

Reject Due To: Gross hemolysis, lipemia, icterus.

Centrifuge samples and transfer 4 mL serum (2 mL minimum) into the RPNPEV aliquot. If specimen volume allows, aliquot 1 mL serum into a separate plastic vial for Immunology (UW437). Prioritize the sendout test (RPNPEV).

• RPNPEV: Refrigerate 4 mL serum (2 mL minimum) in the Sendouts Mayo rack.
• UW437: Freeze 1 mL serum at -20°C in Immunology rack.

If individual antibodies are requested (with a previous positive result within the last 5 years at Mayo), refer to separate test guide #982 (Neuroimmunology Follow-up, PNEFS).

Sendouts:

• Order Mayo Test: PAVAL
• Interfaced: Yes [Interface: 601: Worksheet: MARF]

Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.

Reject Due To: Gross hemolysis, lipemia, icterus.