Collection and normal levels of the amyloid precursor protein in plasma.

The amyloid precursor protein is contained in platelet alpha granules and released with degranulation. Methods are described to control for amyloid precursor protein release from platelets during blood collection and processing. In normal subjects (n = 97; age range, 44-84 years), the average plasma level of amyloid precursor protein was 6.5 +/- 1.8 ng/ml.