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.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- What is hemoglobin?
- How is hemoglobin measured?
- What are normal hemoglobin values?
- What does a low hemoglobin level mean?
- What does a high hemoglobin level mean?
- What is sickle cell disease?
- What is thalassemia?
- What is the hemoglobin A1c test?
What is thalassemia?
Thalassemia refers to a group of hereditary conditions with quantitative hemoglobin deficiency. The body's failure to make globulin molecules will lead to compensatory mechanism to make other less compatible globulin molecules. The different types of thalassemia are defined based on what type of globulin molecule is deficient. The severity of these conditions depends on the type of deficient globulin chain, the number of deficient globulins, and the severity of the underproduction. Mild disease may only present as mild anemia, whereas, severe deficiency may not be compatible with life.
What is the hemoglobin A1c test?
Hemoglobin A1c or glycosylated hemoglobin is a rough indication of blood sugar control in people with diabetes mellitus over the preceding three months. As more glucose (blood sugar) circulates in the blood on a daily basis, more hemoglobin molecules are bound to glucose. Normal hemoglobin A1c level ranges between 4% to 5.9%. As this number reaches 6% or greater, it signifies poorer diabetes control.
Hemoglobin A1c of 6% roughly correlates with average blood sugar level of 135 mg/dL (milligrams per deciliters) over the previous three months. Each 1% increase in hemoglobin A1c above 6% represents average blood sugar of approximately 35 mg/dL over 135 mg/dL. For example, hemoglobin A1c measurement of 7% corresponds to average blood sugar level 170 mg/dL in the last three months.
American Society of Hematology.
MedscapeReference.com. Mean Corpuscular Hemoglobin (MCH) and Mean Corpuscular Hemoglobin Concentration (MCHC).
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