Liam Beiglari,¹ Sean Riminton¹ on behalf of the Concord Neuroimmunology Study Group
¹ Concord Hospital Neuroimmunology Clinic

Paraneoplastic neurological syndromes (PNS) are rare, increasingly reported, and are on the differential diagnosis of a range of neurological presentations. A 2018 paper by Ebright¹ identified a high false positive rate associated with panel testing of autoantibodies for PNS. They identified the “unintended consequences” of testing for PNS including waste and clinical harm. We sought to explore the unintended consequences of these assays in the Australian context by determining the specificity of positive results.

Consecutive results for PNS testing ordered by the Concord Neuroimmunology Service between January 2020 and December 2023 were extracted from the RPA immunopathology laboratory. This included a line blot immunoassay (LIA) (Euroimmun, Paraneoplastic 12 Ag, Lübeck, Germany ) which tests 12 distinct antigen specificities and indirect immunofluorescence (IIF) (Inova Diagnostics, San Diego, USA) on primate brain. Sixty seven positive antigen specificities were compared to clinical data. Duplicates and IIF without positive LIA were excluded from the final analysis.

The final data will be presented in the presentation although preliminary data suggests a high rate of false positives. These data will be used for generating recommendations for amendments to clinical laboratory algorithms in reporting PNS testing.

References:

1.      Ebright MJ, Li S-H, Reynolds EL, Burke JF, Claytor BR, Grisold A, Banerjee M, Callaghan B, Callaghan BC. Unintended consequences of Mayo paraneoplastic evaluations. Neurology 2018;91.