Description
The plasma beta-amyloid 42/40 ratio is a blood test that measures the ratio of amyloid beta 42 to amyloid beta 40 in the plasma. It can help predict the risk of Alzheimer's disease and other dementia, and is used as a supplement to other diagnostic tests:
- What it measures: The ratio of amyloid beta 42 to amyloid beta 40 in the blood
- What it predicts: The risk of Alzheimer's disease and other conditions, including amyloidosis and cerebral amyloidosis
- How it's used: As a supplement to other diagnostic tests, such as neurological and cognitive performance exams and PET neuroimaging
- Why it's useful: The ratio improves the sensitivity and specificity of detecting Alzheimer's disease by normalizing beta amyloid levels across patients
- What it indicates: A lower ratio is associated with a higher risk of Alzheimer's disease, while a higher ratio is associated with a lower risk
The plasma beta-amyloid 42/40 ratio is a peripheral biomarker, meaning the effect is smaller than in cerebrospinal fluid. This is likely due to dilution by amyloid beta peptides from other sources.
Fasting not required.
