The present invention relates to a method for detecting Alzheimer's disease in a subject. This method involves providing a sample from the subject, subjecting the sample to a spectroscopic analysis to produce a spectroscopic signature for the sample, determining whether the spectroscopic signature for the sample corresponds to an Alzheimer's disease spectroscopic signature, and identifying a subject as having Alzheimer's disease where the spectroscopic signature for the sample from that subject corresponds to the spectroscopic signature for Alzheimer's disease. Also disclosed is a method for monitoring Alzheimer's disease progression in a subject, involving providing a sample from a subject with Alzheimer's disease, subjecting the sample to a spectroscopic analysis to produce a spectroscopic signature for the sample, comparing the spectroscopic signature for the sample to a prior spectroscopic signature from the subject or to a spectroscopic signature standard for a specific stage of Alzheimer's disease, and determining the progression of Alzheimer's disease in the subject based on said comparing.