What is hemoglobin? (or Hb, or Hgb).

When people get a test for anemia, it contains a number for the Hemoglobin and another number for Red blood cells. A decrease in those numbers leads to a diagnosis of anemia.

Hemoglobin is a combination of 2 different kinds of protein chains in combination with Iron. It is contained in the Red Blood Cells (RBC) that circulate in the blood. Iron is bound to the protein chains, and acts like a shuttle system for oxygen. It gets oxidized in the lungs, and sheds the oxygen in the body’s tissues, then goes back to the lungs for more.

Why does hemoglobin go down?

Hemoglobin production goes down when there is an iron deficiency, or Vitamin b12 or Folic acid deficiency. B12 and Folic acid are necessary for other enzymes in hemoglobin production.

Iron deficiency can occur mainly with excessive blood loss (menstrual, or gastrointestinal), or diets deficient in iron.

B12/ folate deficiency can occur with dietary deficiency, or stomach bypass surgery, or stomach lining diseases. Antibodies against the Intrinsic Factor (IF) necessary for B12 absorption cause Pernicious Anemia.

 Why do RBC numbers go down?

Erythropoietin is produced in the kidneys, and responds to low oxygen levels in the blood. Increased Epo levels drive increased RBC production. People who live at higher altitudes have greater Epo production, with higher RBC counts. Athletes like to train at higher altitudes, and then compete at lower altitudes, so they can use the extra RBCs (with hemoglobin) to carry extra oxygen while competing. Or they illegally give themselves shots of Epo.

Thyroxine is the hormone produced by the thyroid gland, and is the engine that drives many functions, including RBC production

Many diseases cause RBC numbers to go down:

-Chronic conditions like diabetes or inflammatory arthritis

-Bone marrow diseases like multiple myeloma or leukemia

-Chemotherapy, which causes an interruption in the production line.

Inherited Anemias are inherited defects in the globin protein chains, e.g. thalassemias. They can masquerade as iron deficiency anemia, but no iron is going to correct these. Thalassemias can be mild and asymptomatic, or severe, requiring regular blood transfusions.

 

A CBC (complete blood count) is part of a routine annual check up. An abnormality of these numbers is a red flag, and needs to be addressed.