{"doi":"10.1002/dad2.70139","title":"Clinical validation of the Lilly SP‐X P‐tau217 assay: Performance in underrepresented cohorts","abstract":"<jats:title>Abstract</jats:title><jats:sec><jats:title>INRODUCTION</jats:title><jats:p>Plasma phosphorylated tau217 (p‐tau217) is a biomarker for the detection of amyloid pathology. We present performance characteristics of the Lilly SP‐X P‐tau217 assay in a clinical validation cohort, as a whole and divided into subpopulations from traditionally underrepresented groups.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>We measured p‐tau217 levels in plasma samples from participants with mild cognitive impairment. Assay performance in predicting positivity for amyloid beta (Aβ) positron emission tomography was examined using two numerical cutoffs.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Two p‐tau217 cutoffs were determined with an upper‐level group with 95% positive predictive value for Aβ positivity and a lower‐level group with 84% negative predictive value for Aβ negativity, with 91% sensitivity and 90% specificity. The remaining indeterminate group represented 18% of participant samples. Similar performance was observed across validation subgroups.</jats:p></jats:sec><jats:sec><jats:title>Discussion</jats:title><jats:p>The validation data support the potential clinical utility of the SP‐X p‐tau217 assay in multiple subpopulations to aid in Alzheimer's disease diagnosis.</jats:p></jats:sec><jats:sec><jats:title>Highlights</jats:title><jats:p><jats:list list-type=\"bullet\">\n<jats:list-item><jats:p>The Lilly SP‐X p‐tau217 assay showed strong concordance with amyloid PET in total cohort and underrepresented groups.</jats:p></jats:list-item>\n<jats:list-item><jats:p>Assay performance is in line with guidance from the Global CEOi on AD Working Group.</jats:p></jats:list-item>\n<jats:list-item><jats:p>Data support the clinical utility of the assay in multiple cohorts to aid in AD diagnosis.</jats:p></jats:list-item>\n</jats:list></jats:p></jats:sec>","journal":"Alzheimer's &amp; Dementia: Diagnosis, Assessment &amp; Disease Monitoring","year":2025,"id":638123,"datarank":0.20794415416798362,"base_score":1.3862943611198906,"endowment":1.3862943611198906,"self_citation_contribution":0.20794415416798362,"citation_network_contribution":0.0,"self_endowment_contribution":0.20794415416798362,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":3,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1657210,"name":"Adam Abel","orcid":null,"position":1,"is_corresponding":false},{"id":762749,"name":"Antonio Chambers","orcid":null,"position":2,"is_corresponding":false},{"id":1143800,"name":"Ming Lu","orcid":"0000-0003-2763-2561","position":3,"is_corresponding":false},{"id":577502,"name":"Amanda Morris","orcid":"0000-0002-6297-5255","position":4,"is_corresponding":false},{"id":618764,"name":"Michael J. Pontecorvo","orcid":"0000-0002-8419-7589","position":5,"is_corresponding":false},{"id":1657215,"name":"Heinz Reiske","orcid":null,"position":6,"is_corresponding":false},{"id":236167,"name":"Samantha C. Burnham","orcid":"0000-0003-4805-5193","position":7,"is_corresponding":false},{"id":394492,"name":"Emily C. Collins","orcid":"0000-0001-9396-536X","position":8,"is_corresponding":false},{"id":1657216,"name":"Mark Mintun","orcid":null,"position":9,"is_corresponding":false},{"id":1657217,"name":"Andrew Schade","orcid":null,"position":10,"is_corresponding":false},{"id":1657218,"name":"Rose C. Beck","orcid":null,"position":11,"is_corresponding":false},{"id":974180,"name":"Michael E. Hodsdon","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"resolved":true,"title":"Clinical validation of the Lilly SP‐X P‐tau217 assay: Performance in underrepresented cohorts","abstract":"<jats:title>Abstract</jats:title><jats:sec><jats:title>INRODUCTION</jats:title><jats:p>Plasma phosphorylated tau217 (p‐tau217) is a biomarker for the detection of amyloid pathology. We present performance characteristics of the Lilly SP‐X P‐tau217 assay in a clinical validation cohort, as a whole and divided into subpopulations from traditionally underrepresented groups.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>We measured p‐tau217 levels in plasma samples from participants with mild cognitive impairment. Assay performance in predicting positivity for amyloid beta (Aβ) positron emission tomography was examined using two numerical cutoffs.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Two p‐tau217 cutoffs were determined with an upper‐level group with 95% positive predictive value for Aβ positivity and a lower‐level group with 84% negative predictive value for Aβ negativity, with 91% sensitivity and 90% specificity. The remaining indeterminate group represented 18% of participant samples. 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