F4–01–04: Blood‐based biomarkers of Alzheimer's disease: Lessons to be learned from studies of cerebrospinal fluid markers

also vary. Sample collection tubes also vary across studies. When looking at serum vs. plasma, many markers correlate highly across blood fraction; however, the link betweenAD status and biomarkers varied according towhether it wasmeasured in serum or plasma. The correlations between the same proteins in the same participants (at same blood draw) across assay platforms was poor. Conclusions: STAR-B is intended to provide the field with best practice guidelines and standards in order to move the field towards implementation (clinical and research). Initial findings by the working group are that the pre-analytic methods across current studies vary considerably, which can have a significant impact on projects aimed at cross-validation. Additionally, the choice of serumversus plasma has a significant impact on biomarker utility even when correlations across blood fractions are high. Platform considerations are also going to be very important once the pre-analytic methods have been addressed.