Blood tests | HIV serology, anti-Ro/La antibodies, anti-Hu antibodies |
CSF | Inflammatory CSF favours a paraneoplastic origin whereas a normal CSF is more likely due to immune or drug induced causes |
Imaging | If malignancy is suspected or anti-Hu antibodies are positive: CT chest with contrast, mammogram, pelvic and abdominal CT and, if required, FDG-PET scanning |
Tissue biopsy | Biopsy of suspicious mass seen on imaging studies to confirm malignancy; lip biopsy for tissue confirmation of Sjögren's syndrome even in those patients who are anti-Ro/La antibody negative |
FDG PET, fluorodeoxyglucose–positron emission tomography.