Clinical information and neuropathological and diagnostic investigations in eight patients with ’false’ positive CSF RT-QuIC results
| Case | CSF RT-QuIC result | Final diagnosis | Disease duration (months) | Immunohistochemistry/western blotting for PrPSc | CSF 14-3-3 | Diffusion-weighted MRI |
| 1 | Positive | Vascular dementia | 17 | Not performed | Positive | Vascular changes |
| 2 | Positive | Suspected frontotemporal dementia (lost to follow-up) | 17 | Not performed | Negative | Negative |
| 3 | Positive | Rapid progressive dementia with paraneoplastic syndrome | 4 | Not performed | Positive | NA |
| 4 | Positive | Diffuse dementia with Lewy bodies | NA | Negative/Positive | Not done | NA |
| 5 | Positive | Alzheimer’s disease | NA | Not performed | Negative | NA |
| 6 | Positive | Encephalopathy presenting with convulsion | NA | Not performed | Positive | Cortical hyperintensity |
| 7 | Positive (slowly amplified) | FTLD-TDP43 with motor neurone disease | NA | Negative/Negative | Negative | NAD |
| 8 | Positive (slowly and slightly amplified) | Steroid-responsive encephalopathy presenting with convulsion | 3 | Negative/Negative | Positive | Cortical hyperintensity during acute phase |
CSF, cerebrospinal fluid; FTLD-TDP43, frontotemporal lobar degeneration-TAR DNA-binding protein 43 kDa;NA, not available;NAD, no abnormality detected; PrP, prion protein; RT-QuIC, real-time quaking-induced conversion.