Preliminary Study for a Multicenter Study of Alzheimer's Disease Cerebrospinal Fluid Biomarkers

A Consensus in Korea Regarding a Protocol to Reduce Preanalytical Sources of Variability in the Measurement of the Cerebrospinal Fluid Biomarkers of Alzheimer's Disease

“…The ADNI and Washington University require at least 6 hours of fasting (and preferably overnight) prior to an LP, while the ABSI does not. A single Korean study indicated that fasting is mandatory, 21 but others indicated that it was not. 28 , 31 Only one study involving a small number of healthy subjects has examined the effects of fasting on Aβ concentrations.…”

“… 24 Accordingly, it is suggested that 15-mL sterile centrifuge tubes with a conical bottom (#352096, BD Falcon, Bedford, MA, USA; or other standardized tubes) should be used as the standard collection tube, as described previously. 21 Similarly, the standard storage tubes should be 500-µL sterile polypropylene tubes with screw caps (cat. 72.730.006 or 72.730.005, Sarstedt, Nümbrecht, Germany; or other standardized tubes), as described in the protocols from ADNI and other laboratories.…”

“…If only Aβ42 and tau proteins are to be analyzed, then delayed freezing may be possible, but the future validation of novel biomarkers for AD diagnosis may require shorter time delays prior to freezing, as suggested by the protocols of the ADNI, Washington University, and ENB, 23 as well as the present authors. 21 Thus, a delay of no more than 4 hours at room temperature prior to deep freezing is suggested, and it is recommended that the time period before freezing is recorded for each individual sample.…”

“…Recent preliminary validations performed in Korea have demonstrated that the tTau/Aβ42 and pTau181/Aβ42 ratios in CSF are highly sensitive and specific for the diagnosis of AD. 21 The trial was conducted to assess the potential of enzyme-linked immunosorbent assay (ELISA) methods to measure AD biomarkers in CSF to be approved for their use from the New Health Technology Assessment of Ministry for Health, Welfare & Family Affairs of Korea ( http://neca.re.kr/nHTA/index.jsp ). However, before CSF AD biomarker assays can be adopted unconditionally as a reliable tool in clinical practice, there must be a quality control program in place for the individual protocol steps to further improve the reliability and accuracy of these measurements; consistent reference and cutoff values for the AD biomarkers commonly used in Korea must also be established.…”

“…Six research centers with experience and continued interest in the analysis of AD biomarkers in CSF were involved in the creation of this consensus. The opinions of the participants were obtained regarding the individual steps of our own protocols 21 , 28 and those available from international biomarker laboratories or networks, including the Alzheimer's Disease Neuroimaging Initiative (ADNI; http://www.alzforum.org/sites/default/files/protocol_Biofluid_Sample_Collection_Protocol_for_ADNI_0.pdf ; http://adni.loni.usc.edu/wp-content/uploads/2008/07/adni2-procedures-manual.pdf ), the Alzheimer's Association (AA; http://www.alzforum.org/sites/default/files/protocol_Flow_Chart_for_Lumbar_Puncture_CSF_Processing_0.pdf ), Washington University ( http://www.alzforum.org/sites/default/files/protocol_CSF_sample_collection.pdf ), 29 the Alzheimer's Biomarker Standardization Initiative (ABSI), 24 the European Network for Biomarkers (ENB), 23 and the recent updates of the last two protocols, which focus on the biomarkers of AD and Parkinson's disease (PD) 25 ( Table 1 ). If any inconsistencies were found between current and previously used protocols, they were discussed prior to reaching the final consensus.…”