{"id":"9a55d4ff-e3e2-5e7d-818a-f90a335f50b9","stable_key":"46d15d9e-d3b5-544d-ba01-b785aa3e4f42:thiamine-def-direct-functional-assay-discordance","predicate":"not-identical-to-classification-by","statement":"Some at-risk patients had low erythrocyte ThDP with a normal activation test, and one had an abnormal activation test with normal ThDP.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"d7b43dcd-347b-56d2-9e56-0b9848334dbb","mechanism_event_label":"The direct and functional tests sometimes classified the same patient differently.","subject":{"id":"fff22d5c-def5-56a2-9dde-f9667bece0a5","slug":"erythrocyte-thdp-concentration","display_name":"Erythrocyte thiamine diphosphate concentration","entity_type_key":"cellular_process"},"object":{"id":"94381007-9bd0-51cc-895d-988aa3eed6c6","slug":"erythrocyte-transketolase-activation-coefficient","display_name":"Erythrocyte transketolase activation coefficient","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"d7b43dcd-347b-56d2-9e56-0b9848334dbb","stable_key":"46d15d9e-d3b5-544d-ba01-b785aa3e4f42:thiamine-def-direct-functional-assay-discordance-event","event_type":"observed_intervention","label":"The direct and functional tests sometimes classified the same patient differently.","description":"Some at-risk patients had low erythrocyte ThDP with a normal activation test, and one had an abnormal activation test with normal ThDP.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"c95c645c-ae67-5911-871e-4f796a17faec","slug":"tkt","display_name":"Human transketolase","entity_type_key":"protein"},"role":"functional assay enzyme","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"fff22d5c-def5-56a2-9dde-f9667bece0a5","slug":"erythrocyte-thdp-concentration","display_name":"Erythrocyte thiamine diphosphate concentration","entity_type_key":"cellular_process"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"94381007-9bd0-51cc-895d-988aa3eed6c6","slug":"erythrocyte-transketolase-activation-coefficient","display_name":"Erythrocyte transketolase activation coefficient","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"biomarker_context","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"evidence_location","value_text":"Abstract Results; classification comparison","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"evidence_span","value_text":"normal by the activation test but had low TDP","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Human method-comparison study: HPLC erythrocyte/whole-blood ThDP, healthy reference cohorts and 63 patients considered at risk of deficiency compared with a transketolase activation test.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Laboratory assessment of thiamine status using erythrocytes or whole blood","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Neither assay was independently validated against brain ThDP; no pooled sensitivity or specificity is inferred. The abstract contains inconsistent category totals, so no concordance percentage is calculated.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Thiamine research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"thiamine","display_name":"Thiamine (vitamin B1)","entity_type_key":"small_molecule"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"The direct and functional tests sometimes classified the same patient differently.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[talwar-2000-blood-thdp] Vitamin B(1) status assessed by direct measurement of thiamin pyrophosphate in erythrocytes or whole blood by HPLC: comparison with erythrocyte transketolase activation assay (2000). https://pubmed.ncbi.nlm.nih.gov/10794754/ DOI: 10.1093/clinchem/46.5.704","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Blood","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"trigger_kind","value_text":"biomarker_context","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null}],"evidence":[{"id":"896f8a23-e2b0-504b-abf6-2332133f08b5","evidence_kind":"source_excerpt","locator":"Lines 1423-1435","start_line":1423,"end_line":1435,"excerpt":"### thiamine-def-direct-functional-assay-discordance\nSome at-risk patients had low erythrocyte ThDP with a normal activation test, and one had an abnormal activation test with normal ThDP.\nCondition category: biomarker_context\nnutrient_topic: Thiamine research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: The direct and functional tests sometimes classified the same patient differently.\norganism: Homo sapiens\ntissue_or_cell_type: Blood\nexperimental_model: Human method-comparison study: HPLC erythrocyte/whole-blood ThDP, healthy reference cohorts and 63 patients considered at risk of deficiency compared with a transketolase activation test.\nlimitations: Neither assay was independently validated against brain ThDP; no pooled sensitivity or specificity is inferred. The abstract contains inconsistent category totals, so no concordance percentage is calculated.\nevidence_location: Abstract Results; classification comparison\nevidence_span: normal by the activation test but had low TDP\nexposure: Laboratory assessment of thiamine status using erythrocytes or whole blood\n[talwar-2000-blood-thdp] Vitamin B(1) status assessed by direct measurement of thiamin pyrophosphate in erythrocytes or whole blood by HPLC: comparison with erythrocyte transketolase activation assay (2000). https://pubmed.ncbi.nlm.nih.gov/10794754/ DOI: 10.1093/clinchem/46.5.704","model_system":"Human method-comparison study: HPLC erythrocyte/whole-blood ThDP, healthy reference cohorts and 63 patients considered at risk of deficiency compared with a transketolase activation test.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [talwar-2000-blood-thdp] Vitamin B(1) status assessed by direct measurement of thiamin pyrophosphate in erythrocytes or whole blood by HPLC: comparison with erythrocyte transketolase activation assay (2000). https://pubmed.ncbi.nlm.nih.gov/10794754/ DOI: 10.1093/clinchem/46.5.704","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"158d2c03-ac8c-589f-8270-c468165ae346","stable_key":"import-46d15d9e-d3b5-544d-ba01-b785aa3e4f42","title":"Thiamine: mechanisms, deficiency and nutrient interactions (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"f376512fb3310141315548015b387833e3af45146e73fb73cd02cee20e4ddb9c","revision_id":"53bc5eda-dec8-58cc-a56f-a9eb4ab036ef","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}