{"id":"1a5547d6-898e-5f64-b828-5fe8bfffe71a","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-serum-normal-recognized-cases","predicate":"above_threshold_did_not_exclude_recognized_deficiency","statement":"Twelve of 419 recognized B12-deficient patients had serum cobalamin above 200 pg/mL; five had prominent neurologic involvement that responded to therapy.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"2c33169e-51f8-53a9-8f78-034f0dad2d09","mechanism_event_label":"A single circulating B12 measurement is not a complete picture of function.","subject":{"id":"8390898f-7915-5c30-8ada-c416a386f5f3","slug":"serum-cobalamin-concentration","display_name":"Serum cobalamin concentration","entity_type_key":"cellular_process"},"object":{"id":"f6446e4d-cd6a-5d7e-889e-b2eb19e27940","slug":"b12-neuropsychiatric-impairment","display_name":"B12-associated neuropsychiatric impairment","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"2c33169e-51f8-53a9-8f78-034f0dad2d09","stable_key":"7fc92b9e-9cbf-556e-8719-6b5244625250:b12-serum-normal-recognized-cases-event","event_type":"observed_intervention","label":"A single circulating B12 measurement is not a complete picture of function.","description":"Twelve of 419 recognized B12-deficient patients had serum cobalamin above 200 pg/mL; five had prominent neurologic involvement that responded to therapy.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"8390898f-7915-5c30-8ada-c416a386f5f3","slug":"serum-cobalamin-concentration","display_name":"Serum cobalamin concentration","entity_type_key":"cellular_process"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"f6446e4d-cd6a-5d7e-889e-b2eb19e27940","slug":"b12-neuropsychiatric-impairment","display_name":"B12-associated neuropsychiatric impairment","entity_type_key":"cellular_process"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""}]},"contexts":[{"dimension":"availability_state","value_text":"biomarker_context","comparator":null,"unit":null,"notes":"Imported condition classification; unverified.","entity":null},{"dimension":"experimental_model","value_text":"Maintenance-relapse observations plus a review of 419 recognized B12-deficient patients.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"exposure","value_text":"Serum cobalamin, MMA and total homocysteine measurements; clinical response used in diagnosis.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Retrospective diagnostic attribution; no estimate of specificity in unselected patients. Potential cohort overlap with related reports.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"vitamin-b12","display_name":"Vitamin B12 (cobalamins)","entity_type_key":"chemical_species"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"A single circulating B12 measurement is not a complete picture of function.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[b12-lindenbaum1990] Diagnosis of cobalamin deficiency: II. Relative sensitivities of serum cobalamin, methylmalonic acid, and total homocysteine concentrations (1990). https://pubmed.ncbi.nlm.nih.gov/2339684/ DOI: 10.1002/ajh.2830340205","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Human blood or whole-person endpoints","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":"adfd1644-f8ed-5f1f-b49f-9ecb9de0ebbe","evidence_kind":"source_excerpt","locator":"Lines 1500-1510","start_line":1500,"end_line":1510,"excerpt":"### b12-serum-normal-recognized-cases\nTwelve of 419 recognized B12-deficient patients had serum cobalamin above 200 pg/mL; five had prominent neurologic involvement that responded to therapy.\nCondition category: biomarker_context\nnutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: A single circulating B12 measurement is not a complete picture of function.\norganism: Homo sapiens\ntissue_or_cell_type: Human blood or whole-person endpoints\nexperimental_model: Maintenance-relapse observations plus a review of 419 recognized B12-deficient patients.\nlimitations: Retrospective diagnostic attribution; no estimate of specificity in unselected patients. Potential cohort overlap with related reports.\nexposure: Serum cobalamin, MMA and total homocysteine measurements; clinical response used in diagnosis.\n[b12-lindenbaum1990] Diagnosis of cobalamin deficiency: II. Relative sensitivities of serum cobalamin, methylmalonic acid, and total homocysteine concentrations (1990). https://pubmed.ncbi.nlm.nih.gov/2339684/ DOI: 10.1002/ajh.2830340205","model_system":"Maintenance-relapse observations plus a review of 419 recognized B12-deficient patients.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [b12-lindenbaum1990] Diagnosis of cobalamin deficiency: II. Relative sensitivities of serum cobalamin, methylmalonic acid, and total homocysteine concentrations (1990). https://pubmed.ncbi.nlm.nih.gov/2339684/ DOI: 10.1002/ajh.2830340205","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"73145023-2982-5848-aff2-8d8875d6b9c5","stable_key":"import-7fc92b9e-9cbf-556e-8719-6b5244625250","title":"Vitamin B12: 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":"ad5b3a51d36e856aa7fdfd1cc23f690b094689bad87d28e1a621a54675a01c92","revision_id":"118bd616-0c13-549f-bfeb-bc439715b89c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}