{"id":"614e43b7-8c68-56a2-9b6b-913aeba8f0d6","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:albumin-adjustment-calcium-misclassification","predicate":"imperfectly_predicts","statement":"Common albumin-adjusted calcium formulas generally classified ionized calcium no better than unadjusted total calcium in a 22,658-adult comparison.","claim_class":"observational","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"c0ff059d-74db-5b2d-abdb-1d50c7449665","mechanism_event_label":"Calculated correction is not a direct ionized-calcium test.","subject":{"id":"a4f09f70-6e4d-56eb-835e-222b4e473635","slug":"albumin-adjusted-total-calcium","display_name":"Albumin-adjusted total calcium estimate","entity_type_key":"cellular_process"},"object":{"id":"960cd748-4134-53da-8f12-fed525f60758","slug":"serum-ionized-calcium","display_name":"Serum ionized calcium concentration","entity_type_key":"cellular_process"},"evidence_count":1,"mechanism_event":{"id":"c0ff059d-74db-5b2d-abdb-1d50c7449665","stable_key":"434e1e27-eb90-583a-956b-62472726ffba:albumin-adjustment-calcium-misclassification-event","event_type":"biomarker","label":"Calculated correction is not a direct ionized-calcium test.","description":"Common albumin-adjusted calcium formulas generally classified ionized calcium no better than unadjusted total calcium in a 22,658-adult comparison.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"a4f09f70-6e4d-56eb-835e-222b4e473635","slug":"albumin-adjusted-total-calcium","display_name":"Albumin-adjusted total calcium estimate","entity_type_key":"cellular_process"},"role":"calculated_marker","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"960cd748-4134-53da-8f12-fed525f60758","slug":"serum-ionized-calcium","display_name":"Serum ionized calcium concentration","entity_type_key":"cellular_process"},"role":"reference_measurement","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":"Cross-sectional comparison of paired laboratory tests in 22,658 adults in Alberta","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Cross-sectional tested population; formulas and patient context differ.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Calcium research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"calcium","display_name":"Calcium","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Homo sapiens","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Calculated correction is not a direct ionized-calcium test.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[desgagnes2025] Use of Albumin-Adjusted Calcium Measurements in Clinical Practice (2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC11751745/ DOI: 10.1001/jamanetworkopen.2024.55251","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"research_relationship_category","value_text":"biomarker","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":"7ce9f6a0-4636-53f2-a820-06b3470e2820","evidence_kind":"source_excerpt","locator":"Lines 325-335","start_line":325,"end_line":335,"excerpt":"### albumin-adjustment-calcium-misclassification\nCommon albumin-adjusted calcium formulas generally classified ionized calcium no better than unadjusted total calcium in a 22,658-adult comparison.\nCondition category: biomarker_context\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Calculated correction is not a direct ionized-calcium test.\norganism: Homo sapiens\ntissue_or_cell_type: Blood\nexperimental_model: Cross-sectional comparison of paired laboratory tests in 22,658 adults in Alberta\nlimitations: Cross-sectional tested population; formulas and patient context differ.\nresearch_relationship_category: biomarker\n[desgagnes2025] Use of Albumin-Adjusted Calcium Measurements in Clinical Practice (2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC11751745/ DOI: 10.1001/jamanetworkopen.2024.55251","model_system":"Cross-sectional comparison of paired laboratory tests in 22,658 adults in Alberta","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [desgagnes2025] Use of Albumin-Adjusted Calcium Measurements in Clinical Practice (2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC11751745/ DOI: 10.1001/jamanetworkopen.2024.55251","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"3c083fa0-59c6-50e9-af42-678d0e3c1006","stable_key":"import-434e1e27-eb90-583a-956b-62472726ffba","title":"Calcium: mechanism-first literature curation (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":"965c934d6b147f2b62f8d45ce6d7a87681a600bfe5c46a585b4704889afd3fc1","revision_id":"543ec48b-4f70-5197-9d76-f5a3c443664c","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[{"id":"21a03b7b-8fef-516e-8a9f-16077c7f30a9","title":"Circulating calcium and whole-body adequacy answer different questions","kind":"qualification","status":"qualified","why":"Total and ionized measurements can disagree, and normocalcemia can persist despite malabsorption.","resolution":"Curation interpretation: Preserve marker identity and clinical/model context; a blood value alone cannot establish dietary adequacy.","created_at":"2026-09-17 08:08:54","record_type":"qualification","display_label":"Source qualification","record_url":"/corrections/21a03b7b-8fef-516e-8a9f-16077c7f30a9","sides":[{"conflict_id":"21a03b7b-8fef-516e-8a9f-16077c7f30a9","ordinal":0,"label":"Total and ionized calcium are different measurements.","revision_id":"543ec48b-4f70-5197-9d76-f5a3c443664c","start_line":313,"end_line":323,"quote":"### total-calcium-imperfect-ionized-proxy-ckd\nIn 691 patients with stage 3-5 CKD, total calcium showed only fair agreement with ionized-calcium classification.\nCondition category: biomarker_context\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Total and ionized calcium are different measurements.\norganism: Homo sapiens\ntissue_or_cell_type: Blood\nexperimental_model: 691 patients with stage 3-5 chronic kidney disease; paired calcium measurements\nlimitations: CKD cohort; albumin correction did not improve prediction.\nresearch_relationship_category: biomarker\n[gauci2008] Pitfalls of measuring total blood calcium in patients with CKD (2008). https://pmc.ncbi.nlm.nih.gov/articles/PMC2488254/ DOI: 10.1681/ASN.2007040449","source_key":"import-434e1e27-eb90-583a-956b-62472726ffba","source_title":"Calcium: mechanism-first literature curation (2026-09-17)","claim_ids":["7394a38c-bc0f-5922-9be3-8cf03e6cb48a"]},{"conflict_id":"21a03b7b-8fef-516e-8a9f-16077c7f30a9","ordinal":1,"label":"Calculated correction is not a direct ionized-calcium test.","revision_id":"543ec48b-4f70-5197-9d76-f5a3c443664c","start_line":325,"end_line":335,"quote":"### albumin-adjustment-calcium-misclassification\nCommon albumin-adjusted calcium formulas generally classified ionized calcium no better than unadjusted total calcium in a 22,658-adult comparison.\nCondition category: biomarker_context\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Calculated correction is not a direct ionized-calcium test.\norganism: Homo sapiens\ntissue_or_cell_type: Blood\nexperimental_model: Cross-sectional comparison of paired laboratory tests in 22,658 adults in Alberta\nlimitations: Cross-sectional tested population; formulas and patient context differ.\nresearch_relationship_category: biomarker\n[desgagnes2025] Use of Albumin-Adjusted Calcium Measurements in Clinical Practice (2025). https://pmc.ncbi.nlm.nih.gov/articles/PMC11751745/ DOI: 10.1001/jamanetworkopen.2024.55251","source_key":"import-434e1e27-eb90-583a-956b-62472726ffba","source_title":"Calcium: mechanism-first literature curation (2026-09-17)","claim_ids":["614e43b7-8c68-56a2-9b6b-913aeba8f0d6"]},{"conflict_id":"21a03b7b-8fef-516e-8a9f-16077c7f30a9","ordinal":2,"label":"Normal blood calcium can coexist with inadequate skeletal supply.","revision_id":"543ec48b-4f70-5197-9d76-f5a3c443664c","start_line":337,"end_line":347,"quote":"### normal-serum-calcium-does-not-establish-sufficiency\nMice with intestinal Vdr deletion maintained serum calcium despite calcium malabsorption and impaired skeletal mineral storage.\nCondition category: biomarker_context\nnutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Normal blood calcium can coexist with inadequate skeletal supply.\norganism: Mus musculus\ntissue_or_cell_type: Blood, intestine and skeleton\nexperimental_model: Intestinal and osteoblast Vdr deletion, low-calcium diets, and skeletal assays in growing mice\nlimitations: Growing-mouse genetic model; not a validated human dietary diagnostic.\nresearch_relationship_category: biomarker\n[lieben2012] Normocalcemia is maintained in mice under conditions of calcium malabsorption by vitamin D-induced inhibition of bone mineralization (2012). https://pmc.ncbi.nlm.nih.gov/articles/PMC3336970/ DOI: 10.1172/JCI45890","source_key":"import-434e1e27-eb90-583a-956b-62472726ffba","source_title":"Calcium: mechanism-first literature curation (2026-09-17)","claim_ids":["996b9d60-3ea3-50ea-b176-bc6bb49e6dc7"]}]}],"research":null}