Blood-Bases biomarkers for Alzheimer's disease and pre-analytical variation Flashcards
Where can biomarkers be found?
in organs, tissues, and body fluids (blood, CSF)
When (time) are biomarkers for AD measurable?
biomarkers start to change and are measurable decades before onset of symptoms
What are the advantages and disadvantages of having blood vs CSF as a medium for biomarkers?
CSF
Advantages:
- direct communication with brain
- less turnover and protease activity
Disadvantages:
- lumbar punctures are complicated + time-consuming
Blood
Advantages:
- easily accessible
- communication with brain via lymph and lymphatic system
Disadvantages:
- biomarker has to cross BBB –> low
-pre-analytical variation more prominent in blood than CSF
Pre-analytical variation
the source of variation can arise due to patient behaviour, laboratory processing, assay performance
- anything that can alter results of the analysis that is not part of the actual analysis/study and yet influences it
sampling, processing, storage
- Patient –> Diet, exercise, clinical history documentation, sample labelling
- Laboratory processing –> Transport time, temperature, time delay spinning, time and temperature of freezing, type of lab plastics
- Assay performance –> buffer composition, machine settings, complications with protocol, lack of certified material
–> these influences must be investigated to allow for appropriate protocol
Why is it important to study pre-analytical variation?
These influences must be investigated to allow for appropriate protocol
- Show knowledge gaps
Is it useful that this SOP would have a global feasibility? Why?
What is a SOP ?
SOP = Standard Operating Procedure
Why establish a SOP for pre-analytical sample handling?
The establishment of SOPs allows for analysis of samples collected by different groups, either because they used the same methods for specimen handling or because the specimen handling steps are documented in detail
