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Anemia

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Medical Author:

Siamak T. Nabili, MD, MPH

Siamak T. Nabili, MD, MPH

Dr. Nabili received his undergraduate degree from the University of California, San Diego (UCSD), majoring in chemistry and biochemistry. He then completed his graduate degree at the University of California, Los Angeles (UCLA). His graduate training included a specialized fellowship in public health where his research focused on environmental health and health-care delivery and management.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

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.

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What is anemia?

Anemia is a medical condition in which the red blood cell count or hemoglobin is less than normal. The normal level of hemoglobin is generally different in males and females. For men, anemia is typically defined as hemoglobin level of less than 13.5 gram/100ml and in women as hemoglobin of less than 12.0 gram/100ml. These definitions may vary slightly depending on the source and the laboratory reference used.

What causes anemia?

Any process that can disrupt the normal life span of a red blood cell may cause anemia. Normal life span of a red blood cell is typically around 120 days. Red blood cells are made in the bone marrow.

Anemia is caused essentially through two basic pathways. Anemia is either caused:

1. by a decrease in production of red blood cell or hemoglobin, or
   
   
2. by a loss or destruction of blood.

As more common classifications of anemia (low hemoglobin) is based on the MCV, or the volume of individual red blood cells.

1. If the MCV is low (less than 80), the anemia is categorized as microcytic anemia (low cell volume).
   
   
2. If the MCV is in the normal range (80-100), it is called a normocytic anemia (normal cell volume).
   
   
3. If the MCV is high, then it is called a macrocytic anemia (large cell volume).

Looking at each of the components of a complete blood count (CBC), especially the MCV, a physician can gather clues as what may be the most common reason for anemia.