1. Take the Blood Disorders Quiz

Medical Author:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

View Full Profile

Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

View Full Profile

The hemoglobin A1c test is a measure of the approximate glucose level that occurred in a person (usually a person with diabetes) over about a 3 month period by determining the person's per cent of hemoglobin A1c. Hemoglobin A1c is also known as glycated hemoglobin; it is a form of hemoglobin made upon exposure of hemoglobin in the blood stream to glucose.

• Hemoglobin A1c test is based on the fact that as blood sugar (glucose) increases, more sugar is bound to hemoglobin, and more glycated hemoglobin is formed.
• Hemoglobin A1c concentration is related to the average amount of glucose in the blood over about 3 months. Normal amounts of hemoglobin A1c are about 4%–5.9%.
• Hemoglobin A1c at 6% correlates to an average glucose level over 3 months of 135 mg/dl.
• Often, the recommended goal for a person with diabetes is 6.5% hemoglobin A1c (representing a glucose level of 152.5 mg/dl on average).
• Each 1% above 6% hemoglobin A1c represents an increase of 35 mg/dl of glucose.
• Consequently, detecting an 8% concentration of hemoglobin A1c would equal a glucose level of 135 plus 70, or 205 mg/dl average over 3 months.
• Concentrations of 8% or more indicate poor glucose control.

Must Read Articles Related to Hemoglobin Levels

Anemia Anemia can be caused by many conditions and diseases such as iron deficiency, poor diet and nutrition, cancers, bone marrow problems, and more. Symptoms of anem...learn more >>

Chemotherapy Chemotherapy or "chemo" is a treatment for cancer. Depending on the type of cancer an individual has, it can cure cancer, control cancer. or ease cancer symptom...learn more >>

Chronic Obstructive Pulmonary Disease (COPD) Chronic obstructive pulmonary disease, or COPD, is a long-lasting obstruction of the airways that occurs with chronic bronchitis, emphysema, or both. This obstr...learn more >>

See the Entire Hemoglobin Levels Topic Guide »