Comprehensive Alzheimer's Disease Evaluation Panel (CSF)

Comprehensive Alzheimer's Disease Panel in CSF

7 days

Chemiluminescent enzyme immunoassay (CLEIA)

Amyloid-beta 42/40 Ratio: ≥0.073 Neurofilament Light Chain: Age specific Total Tau: ≤ 348 ng/L p-Tau 181/Amyloid-beta 42 Ratio: ≤0.068

CSF AD biomarkers should be interpreted collectively. A reduced Amyloid beta 42/40 ratio supports cerebral amyloid pathology, while increased p-Tau181 supports an AD-associated tau biomarker abnormality. The p-Tau181/Amyloid beta 42 ratio provides an additional integrated measure with strong concordance to amyloid PET. Total tau and NfL provide complementary evidence of neuronal injury or neurodegeneration but are not specific for AD. In an appropriately selected symptomatic patient, a concordant amyloid-abnormal (A+) and phosphorylated-tau-abnormal profile (T+) provide strong biological evidence supporting Alzheimer's disease. Discordant, borderline or unexpected profiles should be correlated with the clinical phenotype and may warrant additional evaluation, including review of pre-analytical factors, neuroimaging or alternative neurological diagnoses.

Accredited NRL Laboratory

Weekly

Cerebrospinal fluid biomarkers are used to support Alzheimer's disease (AD) diagnosis by assessing amyloid and tau pathology along with neuronal injury. A reduced Amyloid beta 42/40 ratio indicates amyloid plaque accumulation, while increased phosphorylated tau (p-Tau181) reflects tau abnormalities; together, especially when combined in the p-Tau181/Amyloid beta 42 ratio, they strongly suggest AD-related pathology.
Total tau and neurofilament light chain (NfL) indicate neuronal damage but are not specific to AD. Interpreting these biomarkers collectively in symptomatic patients provides the best evidence for AD, while inconsistent results require careful clinical correlation and further evaluation.

Tests included in the panel:
p-Tau181
Amyloid-beta 42
Amyloid-beta 40
p-Tau181/Amyloid-beta 42 Ratio
Amyloid-beta 42/Amyloid-beta 40 Ratio
Total Tau (t-Tau)
Neurofilament Light Chain (NfL)

CSF

0.7 mL

Polypropylene tubes

The lumbar puncture should preferably be performed in the morning.

The lumbar puncture should be performed at level L3/L4 or L4/L5. Discard the first few drops, to avoid blood-stained specimens) and collect CSF in an appropriate polypropylene collection tube.

Rejection criteria: Samples received in tubes other than polypropylene e.g. polystyrene