Test Overview
A hemoglobin electrophoresis test is a blood test done to check the
different types of
hemoglobin in the blood. Hemoglobin is the substance
in red blood cells that carries oxygen. See an illustration of
hemoglobin
.
The most common types of normal hemoglobin are:
- Hemoglobin F (fetal
hemoglobin). This type is normally found in
fetuses and newborn babies. Hemoglobin F is replaced
by hemoglobin A (adult hemoglobin) shortly after birth; only very small amounts
of hemoglobin F are made after birth. Some diseases, such as
sickle cell anemia,
aplastic anemia, and
leukemia, have abnormal types of hemoglobin and higher
amounts of hemoglobin F.
- Hemoglobin A. This
is the most common type of hemoglobin found normally in adults. Some diseases,
such as severe forms of
thalassemia, may cause hemoglobin A levels to be low
and hemoglobin F levels to be high.
- Hemoglobin A2. This is a normal
type of hemoglobin found in small amounts in adults.
More than 400 different types of abnormal hemoglobin have been
found, but the most common are:
- Hemoglobin S. This type
of hemoglobin is present in sickle cell anemia.
- Hemoglobin C. This is another type of hemoglobin found in
sickle cell anemia.
- Hemoglobin E. This type
of hemoglobin is found in people of Southeast Asian descent.
- Hemoglobin D. This type of hemoglobin may be present with
sickle cell anemia or thalassemia.
- Hemoglobin H
(heavy hemoglobin). This type of hemoglobin may be present in certain
types of thalassemia.
Hemoglobin S and hemoglobin C are the most common types of abnormal
hemoglobins that may be found by an electrophoresis test.
Electrophoresis uses an electrical current to separate normal and
abnormal types of hemoglobin in the blood. Hemoglobin types have different
electrical charges and move at different speeds. The amount of each hemoglobin
type in the current is measured.
An abnormal amount of normal hemoglobin or an abnormal type of
hemoglobin in the blood may mean that a disease is present. Abnormal hemoglobin
types may be present without any other symptoms, may cause mild diseases that
do not have symptoms, or cause diseases that can be life-threatening. For
example, hemoglobin S is found in sickle cell anemia, which is a serious
abnormality of the blood and cause serious problems.