Alzheimer Disease Markers

General

Synonym/Acronym:
CSF tau protein and Beta-amyloid-42, AD, APP, PS-1, PS-2, ApoE4.

Rationale
To assist in evaluating for Alzheimer disease risk.

Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.

Normal Findings
(Method: Electrochemiluminescent immunoassay for Beta-amyloid-42 and tau protein, and polymerase chain reaction for detection of apolipoprotein E2, E3, E4 alleles as biochemical and genetic markers of Alzheimer disease [AD] risk. Scientific studies indicate that a combination of elevated tau protein and decreased Beta-amyloid-42 protein levels are consistent with the presence of AD.)

Beta-amyloid-42Greater than 1026 pg/mL (these levels correlate with negative findings in an amyloid PET scan)
Tau protein (total)Less than or equal to 238 pg/mL
Phospho-TauLess than or equal to 21.7 pg/mL
ApoE 2–4 allelesHomozygous Apo e3 (e3/e3) is the most commonly identified (normal) pattern; the ApoE4 allele is associated with increased risk of developing AD
The testing laboratory should be consulted for interpretation of results.



Critical Findings and Potential Interventions
N/A

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