Chapter 8 Pre-Analytical and Analytical Critical Factors Influencing the High Variability of the Concentrations Levels of Alzheimer Disease Biomarkers in Cerebral Spinal Fluid

1. Introduction

2. Influence of confounding factors in pre-analytical phases on the analysis of AD biomarkers

2.1. In vivo factors

2.1.1. Is there a specific time of day needed to collect the CSF?

2.1.2. Is fasting able to modify the concentrations levels of AD biomarkers ?

2.2. In vitro factors

2.2.1. Localization of the puncture

2.2.2. Does a CSF gradient of AD biomarkers exist ?

2.2.3. What kind of needle for the puncture ?

2.2.4. Types of sampling tubes

2.2.5. Time delay between CSF collection and storage before assay

2.2.6. Freezing process

3. Variability introduced by the analytical step

3.1. Principles of assays

3.2. Extent of the variability highlighted by this EQC program [37]

3.2.1. Total variability

3.2.2. Within-laboratory precision

3.2.3. Differences in absolute values

3.3. Possible sources of variability

3.3.1. Issues to be solved by manufacturers

4. Conclusion

Author details

References