How Is Idiopathic Thrombocytopenic Purpura
Diagnosed?
To diagnose idiopathic thrombocytopenic purpura
(ITP), your doctor must first be certain that your low platelet count
isnt caused by other conditions, such as HIV infection or lupus, or by
medicines (for example, chemotherapy drugs or aspirin). Your doctor will ask
about your medical history, do a physical exam, and order blood tests.
Your medical history includes information about:
- Your signs and symptoms of bleeding
- Illnesses you have that could lower your platelet
count or cause bleeding
- Medicines or any other over-the-counter
supplements or remedies you take that could cause bleeding or lower your
platelet count
Your doctor will give you a physical exam and look
for signs of bleeding and infection.
He or she also will order blood tests to measure
the platelet count in your blood. These tests usually include:
- A complete blood count. This test shows the
numbers of different kinds of blood cells, including platelets, in a small
sample of your blood. In ITP, the red and white blood cell counts are normal.
- A blood smear. During this test, some of your
blood is put on a slide. A microscope is then used to look at your platelets
and other blood cells.
- Some laboratories may be able to test for the
antibodies that attack platelets.
If blood tests show that you have a low number of
platelets, your doctor may need to order more tests to confirm a diagnosis of
ITP. For example, bone marrow tests may be used to see if the large cells that
make platelets look normal. (These large cells are called megakaryocytes.)
Some people with mild ITP have few or no signs of
bleeding. In that case, they might be diagnosed only after a blood test done
for another reason shows that they have a low number of platelets.
|