We determined that a 1:8 dilution of CSF provided the best combination of matrix tolerance and sensitivity. The product insert illustrates this with part of the validation data used to support the dilution decision. The Human Aß42 Kit is far more sensitive than the other kits you may have used. This increased sensitivity makes it possible to detect the analyte at a 1:8 dilution factor with decreased matrix effects. Other kits do not have comparable sensitivity to the MSD kits, so diluted samples cannot be detected. Existing kits in the market do not show dilution linearity for CSF samples and upon dilution of CSF, the apparent concentration of Aß42 increases (Bjerke, M. et al. 2010. Confounding Factors Influencing Amyloid Beta Concentration in Cerebrospinal Fluid. International Journal of Alzheimer's Disease. doi: 10.4061/2010/986310).