{"id":"hemoglobin-a2","name":"Hemoglobin A2 (HbA2)","shortName":"HbA2","aliases":["Hemoglobin A2","HbA2","Hgb A2","Hb A2","A2 Hemoglobin","Hemoglobin A2 Quant","Hemoglobin A2 (HPLC)","Haemoglobin A2","Hemoglobina A2","HbA2 %","Hemoglobin A2 Quantitation","Hemoglobin A2, Quantitative","Hgb A2 %","HGB A2","Hemoglobin A2 Percent"],"abbreviations":["HbA2","Hb A2","HGB A2","Hgb A2"],"loinc":[{"code":"4551-8","primary":true},{"code":"4552-6","primary":false},{"code":"42245-1","primary":false}],"specimen":"whole-blood","units":[{"ucum":"%","display":"%"}],"referenceRanges":[{"population":"2+","low":2,"high":3.5,"unit":"%","unitDisplay":"%","note":"ARUP (HPLC) gives 2.0–3.5% for ages 2 and over, and the AAFP thalassemia review gives 2% to 3.5% for normal adults. Mayo Clinic Laboratories (capillary electrophoresis) prints 2.0–3.3% from age 6 months, and the University of Iowa prints 0–3.5%. The NHS England antenatal screening programme sets an action value of 3.5% or higher. Methods differ slightly, so use the range printed on your report.","sources":[{"title":"Hemoglobin Evaluation by HPLC With Reflex to Electrophoresis and/or RBC Solubility (test 3017101)","url":"https://ltd.aruplab.com/Tests/Pub/3017101","publisher":"ARUP Laboratories"},{"title":"Alpha- and Beta-thalassemia: Rapid Evidence Review","url":"https://www.aafp.org/pubs/afp/issues/2022/0300/p272.html","publisher":"American Family Physician","year":2022},{"title":"Hemoglobin Variant, A2 and F Quantitation, Blood (test HGBCE)","url":"https://www.testcatalog.org/show/HGBCE","publisher":"Mayo Clinic Laboratories"},{"title":"Hemoglobin Evaluation, Quantitation with Interpretation (Pathology Handbook)","url":"https://www.healthcare.uiowa.edu/path_handbook/handbook/test969.html","publisher":"University of Iowa Hospitals & Clinics"},{"title":"Sickle cell and thalassaemia screening: laboratory handbook, Antenatal screening (updated 10 October 2024)","url":"https://www.gov.uk/government/publications/sct-screening-handbook-for-antenatal-laboratories/antenatal-screening","publisher":"NHS England (NHS Sickle Cell and Thalassaemia Screening Programme)","year":2024}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"The share of your hemoglobin that is the minor form HbA2. It helps clinicians sort out inherited hemoglobin conditions such as beta-thalassemia trait.","url":"https://bloodtesttracker.com/markers/hemoglobin-a2","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}