hemoglobin A1c

noun

: a stable glycoprotein formed when glucose binds to hemoglobin A in the blood

Blood sugar was assessed by measuring the amount of hemoglobin A1c in the participants' blood, a test that looks for hemoglobin with sugar attached to it.

—Gina Kolata

also : a test that measures the level of hemoglobin A1c in the blood as a means of determining the average blood sugar concentrations for the preceding two to three months

Note: Both the glycoprotein and the test are also called A1c, glycated hemoglobin, glycohemoglobin, glycosylated hemoglobin, HA1c, and HbA1c.

Examples of hemoglobin A1c in a Sentence

Recent Examples on the Web

In one study of brown seaweed, participants saw a significant improvement in hemoglobin A1c (HbA1c) levels, an essential measurement of blood sugar control.1 Multiple reviews also report that seaweed positively impacts blood sugar levels, especially in people with type 2 diabetes. —Adrienne Dellwo, Verywell Health, 14 Mar. 2025

That accounts for a number of routine lab tests, including a comprehensive metabolic panel, lipid panel, CBC with differential, hemoglobin A1c and thyroid-stimulating hormone. —John Yoo and John Shu, Newsweek, 23 Jan. 2025

One study found that sulforaphane, in the form of broccoli sprout extract, can help lower fasting blood glucose (sugar) and hemoglobin A1c (HbA1c) levels in people with uncontrolled type 2 diabetes. —Chelsea Rae Bourgeois, Rdn, Ld, Health, 11 Jan. 2025

In addition to helping control hemoglobin A1c and blood glucose levels, fiber decreases inflammation, which helps lower the risk of heart attack and stroke. —Angela Haupt, TIME, 15 Oct. 2024

His hemoglobin A1c was a 6.3 at Canyon Ranch; his doctors at home knew about this and had been trying to get the number to budge to no avail with medication, Metformin. —David Oliver, USA TODAY, 14 Oct. 2024

Talk to your healthcare provider about ideal blood sugar and hemoglobin A1c numbers. —Lana Barhum, Verywell Health, 8 Oct. 2024

One meta-analysis observed significant reductions in fasting glucose and hemoglobin A1c (HbA1c) with 35 mg of zinc supplementation daily. —Melissa Nieves, Verywell Health, 26 Sep. 2024

Those running the trial looked at changes in participants’ hemoglobin A1c (HbA1c), a blood test that shows what a person’s average blood sugar was over the past two to three months. —New Atlas, 10 Sep. 2024

Word History

First Known Use

1964, in the meaning defined above

Medical Definition

hemoglobin A1c

noun

-ˌā-ˌwən-ˈsē

: a stable glycoprotein formed when glucose binds to hemoglobin A in the blood

Blood sugar was assessed by measuring the amount of hemoglobin A1c in the participants' blood, a test that looks for hemoglobin with sugar attached to it.

—Gina Kolata

also : a test that measures the level of hemoglobin A1c in the blood as a means of determining the average blood sugar concentrations for the preceding two to three months

called also A1c, glycated hemoglobin, glycohemoglobin, glycosylated hemoglobin, HA1c, HbA1c