Table 1.

Summary of advantages and disadvantages of saliva as a biological fluid in the determination of biomarkers compared to CSF and blood.

	CSF	Blood	Saliva
Advantages	-Standardized methodology	-Easily accessible and non-invasive collection technique -Inexpensive -Reproducible results -Aβ can bypass through the blood-brain barrier	-Equivalent to serum -Easily accessible and non-invasive collection technique -Inexpensive -Chair-side procedure, does not require hospitalization -Reproducible results at different stages -Lower stress during collection for patients with neurodegenerative diseases
Disadvantages	-Invasive collection technique (lumbar puncture) -Expensive -Requires hospitalization and specialized clinicians	-Non-specific methodology -Low concentration of biomarkers	-Non-specific, non-standardized methodology