{"id":"hemoglobin-a1c","name":"Hemoglobin A1c (HbA1c)","shortName":"A1c","aliases":["Hemoglobin A1c","HbA1c","A1c","Glycohemoglobin","Glycated Hemoglobin","Glycosylated Hemoglobin","Hgb A1c","Glycated haemoglobin","Hemoglobina glicosilada","Hemoglobin A1C","Hb A1c","HbA1c (IFCC)","HbA1c (NGSP)","Hemoglobin A1c (HbA1c)","Glyco Hb","Glycohaemoglobin","Glycosylated Haemoglobin","Hgb A1c, Whole Blood","Hemoglobina A1c","Hemoglobina glicada","Hemoglobina glucosilada","Hémoglobine glyquée","Hemoglobin A1c, Glycated","Glycated Hgb","Glycated Hb"],"abbreviations":["HbA1c","A1c","A1C","HgbA1c","GHb"],"loinc":[{"code":"4548-4","primary":true},{"code":"17856-6","primary":false},{"code":"59261-8","primary":false},{"code":"71875-9","primary":false},{"code":"4549-2","primary":false},{"code":"17855-8","primary":false},{"code":"62388-4","primary":false}],"specimen":"whole-blood","units":[{"ucum":"%","display":"%"},{"ucum":"mmol/mol","display":"mmol/mol"}],"referenceRanges":[{"population":"Adults","low":4.8,"high":5.6,"unit":"%","unitDisplay":"%","note":"Labcorp lists 4.8 to 5.6% as normal, and the ADA 'normal' category is below 5.7% (39 mmol/mol). Other labs may print a different lower limit. In IFCC units this is about 29 to 38 mmol/mol (NGSP % = 0.09148 x IFCC + 2.152). The interval assumes typical red blood cells. Hemoglobin variants, iron deficiency, blood loss, red cell breakdown, pregnancy and advanced kidney disease can move A1c without a matching change in glucose.","sources":[{"title":"Hemoglobin A1c (test 001453)","url":"https://www.labcorp.com/tests/001453/hemoglobin-a1c","publisher":"Labcorp"},{"title":"2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2026","url":"https://pmc.ncbi.nlm.nih.gov/articles/PMC12690183/","publisher":"American Diabetes Association (Diabetes Care)","year":2026},{"title":"Hemoglobin A1C (HbA1c) Test","url":"https://medlineplus.gov/lab-tests/hemoglobin-a1c-hba1c-test/","publisher":"MedlinePlus, National Library of Medicine"},{"title":"IFCC Standardization of HbA1c: IFCC and NGSP","url":"https://ngsp.org/ifccngsp.asp","publisher":"National Glycohemoglobin Standardization Program (NGSP)"},{"title":"Factors that Interfere with HbA1c Test Results","url":"https://ngsp.org/factors.asp","publisher":"National Glycohemoglobin Standardization Program (NGSP)","year":2026}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"A1c shows your average blood sugar over about the past 2 to 3 months, based on how much glucose is stuck to your hemoglobin.","url":"https://bloodtesttracker.com/markers/hemoglobin-a1c","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}