How Is Hemolytic Anemia Diagnosed?
Hemolytic anemia is diagnosed using a combination of
medical and family history, physical exam, and diagnostic tests.
Specialists Involved
Primary care doctors, such as a family doctor or
pediatrician, may be involved in diagnosing and treating hemolytic anemia.
Other kinds of doctors involved include:
- A hematologist (blood disease specialist)
- A cardiologist (heart specialist)
Doctors and clinics that specialize in treating
inherited blood disorders, such as
sickle
cell anemia and
thalassemia,
may be involved. If you have an inherited form of hemolytic anemia, you may
want to consult a genetics counselor.
Medical and Family History
To determine the cause and severity of hemolytic
anemia, your doctor may ask detailed questions about your symptoms, personal
medical history, and your family medical history. You may be asked whether you
or anyone in your family has had problems with
anemia
in the past. Your doctor will want to know what illnesses or conditions you
have had recently and what medicines you take.
You also may be asked whether you have been exposed
to any drugs or chemicals or have an artificial heart valve or device that
could damage red blood cells.
Physical Exam
Your doctor will perform a physical exam to
determine how severe the anemia is and to check for possible causes. This exam
may include:
- Checking for jaundice (yellowish skin and
eyes)
- Listening to your heart for a rapid or abnormal
heartbeat
- Listening for rapid or uneven breathing
- Feeling your abdomen to check the size of your
liver and spleen
- Performing a pelvic and rectal exam to check for
internal bleeding
Diagnostic Tests and Procedures
Your doctor may perform a number of tests, including
the following:
Blood Tests
Complete blood count. Usually, the
first test used to diagnose anemia is a complete blood count (CBC). The CBC
tells a number of things about a person's blood, including:
- The hemoglobin level. Hemoglobin is the iron-rich
protein in red blood cells that carries oxygen through the body. The normal
range of hemoglobin levels for the general population is 11-15 g/dL. A low
hemoglobin level means a person has anemia.
- The hematocrit (hee-MAT-oh-crit) level. The
hematocrit level measures how much of the blood is made up of red blood cells.
The normal range for hematocrit levels for the general population is 32-43
percent. A low hematocrit level is another sign of anemia.
The normal range of these levels may be different in
certain racial and ethnic populations. Your doctor can explain your individual
test results.
The CBC also checks:
- The number of red blood cells. Too few red blood
cells means a person has anemia. A low number of red blood cells is usually
seen with either a low hemoglobin or a low hematocrit level, or both.
- Red blood cell size. The mean cell volume
measures the average size (volume) of red blood cells. Red blood cells can be
normal sized, smaller, or larger, depending on the type of anemia.
- The number of white blood cells. White blood
cells are involved in fighting infection.
- The number of platelets. Platelets are small
cells that are involved in blood clotting.
Additional blood tests. If the CBC
results confirm you have anemia, your doctor may order additional blood tests
to determine the type and cause of the anemia. Some of the tests that can be
used in the diagnosis of hemolytic anemia include:
- Reticulocyte (re-TIK-u-lo-site) count.
Reticulocytes are young red blood cells. The reticulocyte count measures the
rate at which the bone marrow is producing new red blood cells. Typically in
hemolytic anemia, the reticulocyte count is higher than normal because the bone
marrow is working overtime to replace the destroyed red blood cells.
- Peripheral smear. This test involves looking at
the blood cells through a microscope. Some types of hemolytic anemia involve
abnormally shaped red blood cells, which can be seen through a microscope.
- Coombs' test. The Coombs' test measures the
presence of antibodies directed against red blood cells.
- Haptoglobin, bilirubin, and liver function tests.
When red blood cells break down, they release their hemoglobin into the
bloodstream. The hemoglobin combines with a chemical called haptoglobin. A low
level of haptoglobin in the bloodstream is an indication of hemolytic anemia.
Bilirubin comes from the breakdown of hemoglobin. High levels of bilirubin
cause jaundice, a yellowish discoloration to the skin and eyes. High levels of
bilirubin in the blood occur with the hemolysis of red blood cells, and also
with some liver and gallbladder diseases. Liver function tests help to
determine whether high bilirubin levels are from hemolytic anemia or
liver/gallbladder disease.
- Hemoglobin electrophoresis. This test detects
abnormal hemoglobin, which is the cause of some types of hemolytic anemia.
- Testing for paroxysmal nocturnal hemoglobinuria
(PNH). In PNH, the red blood cells are missing certain proteins. The test for
PNH looks for red blood cells that are missing these proteins.
- Osmotic fragility test. This test looks for
abnormally fragile red blood cells, which are seen in hereditary
spherocytosis.
- Testing for glucose-6-phosphate dehydrogenase
deficiency (G6PD) deficiency. This test, called a rapid fluorescent spot test,
detects evidence of G6PD enzyme activity in a sample of blood.
Bone Marrow Tests
In some cases, the doctor may want to examine the
cells of the bone marrow under a microscope. A sample of bone marrow can be
obtained with either a bone marrow biopsy or aspiration. A bone marrow biopsy
is a minor surgical procedure to remove a small amount of bone marrow tissue.
For a bone marrow aspiration, your doctor removes a small amount of bone marrow
fluid through a needle.
Tests for Other Causes of Anemia
Because anemia has many causes, the doctor may order
tests for conditions such as:
- Kidney failure
- Lead poisoning
- Low levels of vitamins, including vitamin B12,
vitamin C, and folate
- Iron deficiency
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