A chaperone protein Q2 and -amyloid can form a complex. This complex can be detected in a biological sample, such as, for example, tissues or fluids from a mammal. Q2 levels can also be detected in a biological sample. A method for detecting the Q2 level is a biological sample and comparing that level to a normal Q2 level can be used to detect, screen, diagnose, or otherwise determine a person's susceptibility to Alzheimer's disease such as, for example, the presence or absence of Alzheimer's disease, of symptoms of this disease, of factors leading to or associated with this disease, of likelihood of developing this disease, and the like. In one embodiment, a decline in Q2 level correlates to an increased likelihood for developing Alzheimer's disease. In another embodiment, a decline in Q2 level correlates to an increase in -amyloid aggregation. The method may further include screening for an apolipoprotein E genetype, which is associated with Alzheimer's disease.