eprintid: 10130389 rev_number: 14 eprint_status: archive userid: 608 dir: disk0/10/13/03/89 datestamp: 2021-07-01 15:44:23 lastmod: 2021-09-17 22:53:10 status_changed: 2021-07-01 15:44:23 type: article metadata_visibility: show creators_name: Ashton, NJ creators_name: Suárez-Calvet, M creators_name: Karikari, TK creators_name: Lantero-Rodriguez, J creators_name: Snellman, A creators_name: Sauer, M creators_name: Simrén, J creators_name: Minguillon, C creators_name: Fauria, K creators_name: Blennow, K creators_name: Zetterberg, H title: Effects of pre-analytical procedures on blood biomarkers for Alzheimer's pathophysiology, glial activation, and neurodegeneration. ispublished: pub divisions: UCL divisions: B02 divisions: C07 divisions: D07 divisions: F86 keywords: amyloid beta, biomarkers, blood, citrate, ethylenediaminetetraacetic acid, glial fibrillary acidic protein, lithium heparin, neurofilament light, phosphorylated tau, pre‐analytics, serum note: © 2021 The Authors. Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring published by Wiley Periodicals, LLC on behalf of Alzheimer's Association This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. abstract: Introduction: We tested how tube types (ethylenediaminetetraacetic acid [EDTA], serum, lithium heparin [LiHep], and citrate) and freeze-thaw cycles affect levels of blood biomarkers for Alzheimer's disease (AD) pathophysiology, glial activation, and neuronal injury. Methods: Amyloid beta (Aβ)42, Aβ40, phosphorylated tau181 (p-tau181), glial fibrillary acidic protein, total tau (t-tau), neurofilament light, and phosphorylated neurofilament heavy protein were measured using single molecule arrays. Results: LiHep demonstrated the highest mean value for all biomarkers. Tube types were highly correlated for most biomarkers (r > 0.95) but gave significantly different absolute concentrations. Weaker correlations between tube types were found for Aβ42/40 (r = 0.63-0.86) and serum t-tau (r = 0.46-0.64). Freeze-thaw cycles highly influenced levels of serum Aβ and t-tau (P < .0001), and minor decreases in EDTA Aβ40 and EDTA p-tau181 were found after freeze-thaw cycle 4 (P < .05). Discussion: The same tube type should be used in research studies on blood biomarkers. Individual concentration cut-offs are needed for each tube type in all tested biomarkers despite being highly correlated. Serum should be avoided for Aβ42, Aβ40, and t-tau. Freeze-thaw cycles > 3 should be avoided for p-tau181. date: 2021-06-02 date_type: published official_url: https://doi.org/10.1002/dad2.12168 oa_status: green full_text_type: pub pmcid: PMC8171159 language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1872633 doi: 10.1002/dad2.12168 pii: DAD212168 lyricists_name: Zetterberg, Henrik lyricists_id: HZETT94 actors_name: Flynn, Bernadette actors_id: BFFLY94 actors_role: owner full_text_status: public publication: Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring volume: 13 number: 1 article_number: e12168 event_location: United States citation: Ashton, NJ; Suárez-Calvet, M; Karikari, TK; Lantero-Rodriguez, J; Snellman, A; Sauer, M; Simrén, J; ... Zetterberg, H; + view all <#> Ashton, NJ; Suárez-Calvet, M; Karikari, TK; Lantero-Rodriguez, J; Snellman, A; Sauer, M; Simrén, J; Minguillon, C; Fauria, K; Blennow, K; Zetterberg, H; - view fewer <#> (2021) Effects of pre-analytical procedures on blood biomarkers for Alzheimer's pathophysiology, glial activation, and neurodegeneration. Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring , 13 (1) , Article e12168. 10.1002/dad2.12168 <https://doi.org/10.1002/dad2.12168>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10130389/1/dad2.12168.pdf