Diagnostic impact of CSF biomarkers in a local hospital memory clinic.

BACKGROUND: CSF biomarkers amyloid-beta 1-42 (Abeta42), total tau (tau) and tau phosphorylated at threonine 181 (ptau-181) are useful diagnostic markers for Alzheimer's disease (AD). We examined the impact of these biomarkers in the diagnostic process in a non-academic memory clinic.

METHODS: One hundred and nine patients with available CSF were included from the local hospital memory clinic. Initially, patients were clinically diagnosed, and the clinician indicated their confidence in the diagnosis. Next the CSF results were presented, and the clinician re-evaluated his initial diagnosis. The main outcomes were changes in initial diagnosis and diagnostic confidence.

RESULTS: Forty-seven patients were initially diagnosed with AD, 26 were diagnosed with another type of dementia, 18 were diagnosed with mild cognitive impairment, and 18 received a non-dementia diagnosis. All biomarkers distinguished between AD and non-dementia (p < 0.01); tau and ptau-181 also distinguished AD from other types of dementia (p < 0.001). After CSF biomarker levels were revealed, 11 diagnoses changed. In 31% of the diagnoses, the clinician gained confidence, while in 10% confidence decreased.

CONCLUSION: We found that knowledge of CSF biomarker profiles changed the diagnosis in 10% of the cases, and confidence in the diagnosis increased for one third of the patients.