Table 2. The consensus regarding the preanalytical processing of CSF AD biomarkers.

Key subject	Recommendation
Neuroimaging prior to LP	Yes, within 1 year
Necessity of fasting	Preferably overnight or at least 6 h. If not, record the time of the last meal*
Timing of LP*	8:00 a.m. to noon (preferably closer to 8:00 a.m.). Exceptions are permitted
Location	L3-L5
Puncture needle	Preferably a 22- to 24-G atraumatic needle. A conventional cutting-edge needle thinner than 19 G may also be used, but requires caution
Drainage method	Drip or syringe drainage of 5 mL using a 24-G atraumatic needle
CSF routine analysis	Yes, using an initial volume of 1-2 mL
Traumatic puncture	Initial samples should be discarded if bloody, with only the clear part collected and then centrifuged immediately
Collection volume	10-12 mL
Type of collection tube	15-mL centrifuge tubes, conical bottom, sterile (cat. 352096, BD Falcon; or other standardized tubes)
Type of storage tube	500-µL PP tubes with a screw cap (cat. 72.730.006 or 72.730.005, Sarstedt; or other standardized tubes)
Additional transfer of CSF	Not permitted
Permitted storage at RT	Up to 4 h
Necessity of centrifugation	2,000×g for 10 min at RT
Aliquot volume	400 µL in a 500-µL PP tube
Freezing*	Deep freezer (-80℃)
Freeze/thaw cycles	One

^*Record the time.

CSF: cerebrospinal fluid, LP: lumbar puncture, RT: room temparature.