Hemoglobin is a pigment that helps carry oxygen in the blood. The pigment is made up of iron and is extremely essential for the body to perform its functions optimally. If the hemoglobin falls below the normal levels, it can cause a condition known as anemia in which the oxygen carrying capacity of blood diminishes. There is however, a condition called sickle cell anemia, in which, the red blood cells are formed in a sickle shape and therefore have a lower capacity for carrying oxygen. These sickle shaped red blood cells also have abnormal hemoglobin known as hemoglobin S.
The sickle cells are destroyed faster than the normal blood cells, causing a shortage of red blood cells at any given time. People may suffer from mild or severe anemia due to sickle cells, depending on how abnormal the hemoglobin is.
Sickle cell anemia is a genetic disorder, but is recessive. A hemoglobin S test is typically done to measure the presence and severity of the condition. If there is a treatment being given for severe anemia, hemoglobin tests can be used to monitor the treatment and test its efficacy. In a case where anemia is especially severe, the patient may need immediate blood transfusions.
A hemoglobin S test is not normally asked to be conducted. It is usually ordered when a child is born to parents who suffer from the disease. A normal hemoglobin test is ordered as a part of a complete blood count. The panel of tests in the complete blood count can be ordered for many reasons. People who have symptoms of anemia or have problems of blood clotting and bleeding may also be asked to get a complete blood count test. Sometimes in the routine test too, it may be seen that the person has sickle shaped red blood cells.
A person suffering from Sickle Cell Anemia may have two genes, one of which manufactures normal red blood cells and another which manufactures the sickle shaped cells. If a person has a condition where both of these genes are manufacturing sickle shaped cells, the resultant anemia is very severe and regular blood transfusions may be required for the body to function normally.
There are certain conditions where the hemoglobin levels decrease naturally. Conditions like pregnancy cause a natural decrease in the hemoglobin levels. Lifestyle habits like smoking can also cause a gradual destruction of red blood cells.