{"doi":"10.1002/alz.13156","title":"Preanalytical stability of plasma/serum brain‐derived tau","abstract":"INTRODUCTION: We investigated the effects of matrix type and reagent batch changes on diagnostic performances and longitudinal trajectories of brain-derived tau (BD-tau). METHODS: We evaluated (i) Cohort 1: paired EDTA plasma and serum from Alzheimer biomarker-positive older adults versus controls (n = 26); and (ii) Cohort 2: n = 79 acute ischemic stroke patients with 265 longitudinal samples across four time points. RESULTS: In Cohort 1, plasma and serum BD-tau were strongly correlated (rho = 0.96, p < 0.0001) with similar diagnostic performances (AUCs >99%) and correlations with CSF total-tau (rho = 0.93-0.94, p < 0.0001). However, absolute concentrations were ∼40% higher in plasma versus serum. In Cohort 2, first and repeated BD-tau measurements showed a near-perfect correlation (rho = 0.96, p < 0.0001), with no significant between-batch concentration differences. In longitudinal analyses, substituting ∼10% of the first-run concentrations for the remeasured values showed overlapping estimated trajectories without significant differences at any time point. DISCUSSION: BD-tau has equivalent diagnostic accuracies, but non-interchangeable absolute concentrations, in plasma versus serum. Furthermore, the analytical robustness is unaffected by batch-to-batch reagent variations. HIGHLIGHTS: Brain-derived tau (BD-tau) is a novel blood-based biomarker that quantifies tau protein of CNS origin. Effects of preanalytical handling procedures on the quality and reproducibility of BD-tau measures are unknown. In two cohorts of n = 105 participants, we compared BD-tau concentrations and diagnostic performances in paired plasma and serum samples, and evaluated impacts of batch-to-batch reagent variations. Paired plasma and serum showed equivalent diagnostic performances to separate amyloid-positive AD from amyloid-negative controls, indicating both can be used independently. Repeated measurements and longitudinal trajectories of plasma BD-tau were unaffected by batch-to-batch reagent variation.","journal":"Alzheimer s & Dementia","year":2023,"id":333307,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":23,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.6586,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1060590,"name":"Alexandre Dias","orcid":"0000-0002-5110-5764","position":1,"is_corresponding":false},{"id":843049,"name":"Michael Turton","orcid":null,"position":2,"is_corresponding":false},{"id":876247,"name":"Rui Magalhães","orcid":"0000-0002-0232-1276","position":3,"is_corresponding":false},{"id":841866,"name":"Przemysław R. Kac","orcid":"0000-0001-5083-0924","position":4,"is_corresponding":false},{"id":876236,"name":"Manuel Correia","orcid":"0000-0001-6218-6072","position":5,"is_corresponding":false},{"id":843050,"name":"Peter Harrison","orcid":null,"position":6,"is_corresponding":false},{"id":27601,"name":"Henrik Zetterberg","orcid":"0000-0003-3930-4354","position":7,"is_corresponding":false},{"id":617530,"name":"Luı́s F. Maia","orcid":"0000-0002-8140-3471","position":8,"is_corresponding":false},{"id":27600,"name":"Kaj Blennow","orcid":"0000-0002-1890-4193","position":9,"is_corresponding":false},{"id":241105,"name":"Thomas K. Karikari","orcid":"0000-0003-1422-4358","position":10,"is_corresponding":false},{"id":839573,"name":"Fernando González‐Ortiz","orcid":"0000-0001-7897-9456","position":0,"is_corresponding":true}],"reference_count":21,"raw_metadata":null,"created_at":"2026-07-19T01:09:39.719497Z","pmid":"37232524","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}