AMARANTH Question

Below when it describes what participants will go through it says they will be subjected to a PET Scan or a lumbar puncture for cerebrospinal fluid (CSF) sampling to document the presence of abnormal levels of beta amyloid. Would this mean that Lympro being a blood test would not be the main use? I do not know the answer and am not a science person so any help is appreciated.

http://www.nia.nih.gov/alzheimers/clinical-tr...e-amaranth