{ "release_id": "f6f6f1b6f50379ed", "id": "cardio:hba1c", "owner": "cardio", "kind": "biomarker", "slug": "hba1c", "name": "HbA1c blood test", "aliases": [ "HbA1c", "A1C", "Glycated hemoglobin", "Hemoglobin A1C" ], "atlases": [ "cardio" ], "summary_plain": "A blood test that shows your average blood sugar level over the past two to three months. It is used to screen for and diagnose type 2 diabetes and prediabetes, and to monitor people who have diabetes.", "summary_technical": "Glycated hemoglobin: the percentage of red blood cells whose hemoglobin carries glucose. In the trials on this site it describes who was enrolled and how treatment changed blood sugar: the SURPASS-CVOT abstract reports a mean baseline level of 8.4 percent, and a trial of a lifestyle intervention reported greater reductions in glycated hemoglobin.", "editorial_state": "draft", "last_substantive_edit": "2026-10-15", "last_evidence_check": null, "next_review_due": null, "identifiers": [ { "scheme": "mesh", "value": "D006442", "normalized_value": "D006442", "match": "exact", "version": "2026", "label": null, "from_source": false } ], "navigation": { "cardio": { "system": [ "metabolism" ], "condition-area": [ "diabetes-and-metabolic-disease" ] } }, "payload": { "measure": "The percentage of red blood cells that have glucose-coated hemoglobin.", "assay_context": "A blood test. It shows the average blood glucose level over about three months because red blood cells live about three months.", "interpretation_claims": [ "cardio:claim-hba1c-use" ] }, "content_digest": "c70ebf205bdac60008f714ffa8e0254e6f69c8f19f8fbe4c06e3780422dd6bb1", "review": { "content_digest": "c70ebf205bdac60008f714ffa8e0254e6f69c8f19f8fbe4c06e3780422dd6bb1", "current": [], "conflicting": [], "stale": [], "inactive": [] }, "claims": [ { "release_id": "f6f6f1b6f50379ed", "id": "cardio:claim-hba1c-use", "owner": "cardio", "subject_entity_id": "cardio:hba1c", "category": "descriptive", "statement": "MedlinePlus says an HbA1c test is a blood test that shows the average level of blood glucose over the past two to three months. It may be used to screen for or diagnose type 2 diabetes and prediabetes, and to help monitor people who have diabetes or prediabetes. It is not used to diagnose type 1 diabetes but may be used to monitor blood glucose levels in type 1 diabetes.", "context": { "id": "cardio:ctx-people-screened-for-or-with-diabetes-medlineplus", "label": "People being screened for, or living with, diabetes or prediabetes (MedlinePlus test page)", "recipient": "mixed", "population": "People who are screened for diabetes or prediabetes with an HbA1c test, and people with diabetes or prediabetes whose condition is monitored with it.", "care_setting": "Not stated; patient information page", "geography": "Not stated; United States federal health agency", "life_stage_note": "All ages; the page gives screening advice by adult age and risk factors", "life_stage_terms": null, "gestational_age_min_days": null, "gestational_age_max_days": null, "gestational_age_basis": null, "postnatal_age_min_days": null, "postnatal_age_max_days": null, "gestational_age_status": null, "postnatal_age_status": null, "followup_description": "Not applicable (descriptive page)", "eligibility": { "inclusion": [], "exclusion": [] } }, "evidence_stage": "not_applicable", "certainty": "not_assessed", "certainty_method": null, "limitations": "A patient-information page from the National Library of Medicine. It gives no diagnostic cut-off values in the passages read, so this atlas gives none.", "editorial_state": "draft", "checked_at": "2026-10-14", "next_review_due": null, "valid_from": null, "valid_to": null, "citations": [ { "evidence_role": "supports", "locator": "What is a hemoglobin A1C (HbA1C) test?, para 1", "applicability_note": "What the test shows.", "snapshot": { "id": "cardio:medlineplus-hba1c-test-2026-10-14", "retrieved_at": "2026-10-14T18:30:06Z", "content_hash": "8b1bc8bb2e92a787e188524a111fd92d7ba8a494de0ff76c36e312f4cd52948a", "source_effective_date": null, "public_archive_url": null, "source_state": "current" }, "source": { "id": "cardio:medlineplus-hba1c-test", "source_type": "webpage", "title": "MedlinePlus medical test: Hemoglobin A1C (HbA1c) Test", "canonical_url": "https://medlineplus.gov/lab-tests/hemoglobin-a1c-hba1c-test/", "identifiers": [], "publication_date": null, "publisher": "U.S. National Library of Medicine (MedlinePlus)", "edition": "MedlinePlus page fetched 2026-10-14; the page footer says last updated May 20, 2025.", "reuse_basis": "The MedlinePlus page on using its content (fetched 2026-10-14 as ch-medlineplus-usingcontent.html, sha256 31267ce9db01, hash only) says works produced by the federal government are not copyrighted, and lists summaries on health topic pages and medical test information as public domain; A.D.A.M. Medical Encyclopedia articles are copyrighted, and this atlas cites none. Please acknowledge MedlinePlus, National Library of Medicine, as the source. The raw page is committed at research/snapshots/ch-medlineplus-hba1c-test.html.", "public_text": "quote" } }, { "evidence_role": "supports", "locator": "What is it used for?, para 2; What is it used for?, para 3; What is it used for?, para 4; What is it used for?, para 5", "applicability_note": "Uses of the test, and the exception for diagnosing type 1 diabetes.", "snapshot": { "id": "cardio:medlineplus-hba1c-test-2026-10-14", "retrieved_at": "2026-10-14T18:30:06Z", "content_hash": "8b1bc8bb2e92a787e188524a111fd92d7ba8a494de0ff76c36e312f4cd52948a", "source_effective_date": null, "public_archive_url": null, "source_state": "current" }, "source": { "id": "cardio:medlineplus-hba1c-test", "source_type": "webpage", "title": "MedlinePlus medical test: Hemoglobin A1C (HbA1c) Test", "canonical_url": "https://medlineplus.gov/lab-tests/hemoglobin-a1c-hba1c-test/", "identifiers": [], "publication_date": null, "publisher": "U.S. National Library of Medicine (MedlinePlus)", "edition": "MedlinePlus page fetched 2026-10-14; the page footer says last updated May 20, 2025.", "reuse_basis": "The MedlinePlus page on using its content (fetched 2026-10-14 as ch-medlineplus-usingcontent.html, sha256 31267ce9db01, hash only) says works produced by the federal government are not copyrighted, and lists summaries on health topic pages and medical test information as public domain; A.D.A.M. Medical Encyclopedia articles are copyrighted, and this atlas cites none. Please acknowledge MedlinePlus, National Library of Medicine, as the source. The raw page is committed at research/snapshots/ch-medlineplus-hba1c-test.html.", "public_text": "quote" } } ], "review": { "content_digest": "e444e2f535c8da7095aedd081953f54610248fcb8a46419ba359565c0ddc2e69", "current": [], "conflicting": [], "stale": [], "inactive": [] }, "api_path": "api/v1/claims/cardio--claim-hba1c-use.json" } ], "decisions": [], "milestones": [], "relationships": { "outgoing": [ { "predicate": "evaluated_for", "label": "Used to screen for, diagnose and monitor type 2 diabetes", "clinical_claim_not_fact": true, "family": "clinical", "other_entity_id": "cardio:type-2-diabetes", "other_entity_in_atlas": true, "claim_id": "cardio:claim-hba1c-use", "evidence": null, "primary": false, "role": null, "valid_from": null, "valid_to": null } ], "incoming": [ { "predicate": "related_to", "label": "Related to", "clinical_claim_not_fact": false, "family": "navigation", "other_entity_id": "core:medlineplus", "other_entity_in_atlas": true, "claim_id": null, "evidence": null, "primary": false, "role": null, "valid_from": null, "valid_to": null }, { "predicate": "investigates", "label": "Investigated in", "clinical_claim_not_fact": false, "family": "sourced", "other_entity_id": "cardio:surpass-cvot", "other_entity_in_atlas": true, "claim_id": null, "evidence": { "snapshot_id": "cardio:ctgov-nct04255433-2026-10-14", "locator": "protocolSection.outcomesModule.secondaryOutcomes[9].measure" }, "primary": false, "role": null, "valid_from": null, "valid_to": null } ] }, "page_path": "biomarkers/hba1c/", "context_path": "api/v1/context/cardio--hba1c.md" }