The use, misuse and abuse of paraneoplastic panels in neurological disorders. A retrospective study

The field of paraneoplastic neurological syndromes PNS has grown exponentially with the increased identification of associated antibodies. Testing for these antibodies is commonly done in "panels" to increase sensitivity, and these panels have become a routine test on CSF samples obtained for a variety of clinical indications. Excessive testing has raised concerns about the correct utilization of these panels. Our study investigates the appropriateness of use of paraneoplastic panel in an academic, tertiary-care medical center.

We retrospectively reviewed charts of all patients who had autoimmune paraneoplastic panel testing in one year period. We collected date on demographics, clinical presentations and ancillary testings on all reviewed charts. Then, we devised an algorithm based on available data to define cases where testing had been unnecessary or likely unnecessary.

We collected 60 cases that had undergone autoimmune paraneoplastic testing serum and/or CSF. Testing was unnecessary in 10 cases (16%), in which presentations had a definitive confirmatory tests. Testing was unlikely necessary in 11 cases (18%), in which all ancillary testing was normal in 6 cases, and presentation was not compatible with any known syndrome in 5 cases. Collectively, paraneoplastic panel testing was of extremely low yield on more than one third of the cases where where w testing was done.

Our results adds to the growing concerns about the utilization of paraneoplastic panels, and the urgent need for enhanced screening and establishing a framework that can guide neurologists on when testing can have a sufficient yield to warrant it. Such framework should be built using diagnostic algorithms based on risk, clinical manifestations, characterization of autoantibodies and their associations.