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 does a low hemoglobin level mean?
A low hemoglobin level is referred to as anemia or low red blood count. Lower than normal number of red blood cells is referred to as anemia and hemoglobin level reflects this number. There are many reasons (causes) for anemia.
Some of the more common causes of anemia are:
- loss of blood (traumatic injury, surgery, bleeding, colon cancer or stomach ulcer),
- nutritional deficiency (iron, vitamin B12, folate),
- bone marrow problems (replacement of bone marrow by cancer),
- suppression by red blood cell synthesis by chemotherapy drugs,
- kidney failure, and
- abnormal hemoglobin structure (sickle cell anemia or thalassemia).
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