Brain & Nerves
Blood markers of nerve injury and Alzheimer's disease pathology.
5 tests explained
Common follow-up tests
- Amyloid Beta 42/40 Ratio, PlasmaThe ratio of two amyloid peptides in blood plasma. A lower ratio can be a sign of amyloid build-up in the brain, and each lab method has its own cutoff.
- Neurofilament Light Chain (NfL)A protein released when nerve cells are injured. Levels rise with age, so labs use age-based ranges, and a high result does not point to one cause.
- p-tau181 (Phosphorylated Tau 181)A form of tau protein in blood plasma. A result at or below the lab's cutoff makes amyloid changes less likely; a result above it calls for more testing.
- p-tau217 (Phosphorylated Tau 217)A form of tau protein in blood plasma. Higher levels are linked to amyloid build-up in the brain, and each lab's method has its own cutoffs.
- Plasma p-tau217 / Abeta42 Ratio (Lumipulse)A calculated ratio of two plasma proteins, p-tau217 divided by amyloid beta 42. A higher ratio makes amyloid build-up in the brain more likely.