Overview of Blood Disorders

Blood disorders involve problems with your blood or bone marrow, the fatty areas within your bones where new red blood cells, white blood cells, and platelets are produced. You may be diagnosed with a blood disorder when there is a problem with any of these cell types or with the clotting factors (the liquid part of the blood) in the plasma. The most common types are anemia, bleeding disorders (such as hemophilia), and blood clots.

Generally, when doctors call something a blood disorder, they imply that the disorder is not cancerous (ie, leukemia or lymphoma).

type and reason

Blood disorders can be inherited or acquired. Sometimes you can develop blood disorders from infections, exposure to toxic substances, drug side effects, or a lack of certain nutrients in your diet, such as iron, vitamin K, or vitamin B12.

A blood disorder is defined as a change in any part of the blood:

  • White blood cells, which help fight infection: They include neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
  • red blood cells, which carry oxygen to tissues
  • Platelets, which help stop bleeding
  • Plasma, which carries various components, including procoagulant factors (which help stop bleeding) and anticoagulant factors (which prevent clots from forming)

The following are common blood disorders:

  • Neutropenia is a decrease in the number of neutrophils (a type of white blood cell). Neutrophils are an important part of the immune system and help fight bacterial infections. There are many causes, including autoimmune neutropenia, Shwachman-Diamond syndrome, and cyclic neutropenia.
  • Anemia is caused by a decrease in the number of red blood cells or hemoglobin (the protein that carries oxygen). Anemia can be caused by iron deficiency, sickle cell disease, or thalassemia.
  • Polycythemia vera (PV) is a disorder in which the bone marrow produces too many red blood cells. This increase can increase your risk of clot formation.
  • Immune thrombocytopenic purpura (ITP) is a condition in which your platelets are marked as “foreign” and destroyed as a result. This can lead to very low platelet counts and bleeding.
  • Thrombocytosis is an increase in the number of platelets. Fortunately, in most cases, elevated platelet counts are caused by other causes (reactive thrombocythemia) and get better when the underlying condition improves. More concerning, however, are blood conditions such as essential thrombocythemia (ET), in which your bone marrow produces large numbers of platelets, increasing your risk of blood clots and sometimes bleeding.
  • Hemophilia is an inherited disorder that causes a decrease in the number of procoagulant factors (especially 8, 9, and 11). This leads to easy bleeding. People with hemophilia are sometimes called “free bleeders.”
  • Blood clots (thrombosis) can occur anywhere in the body. In the brain, it’s called a stroke; in the heart, it’s called a heart attack (or myocardial infarction). Deep vein thrombosis (DVT) usually refers to a blood clot in the arm or leg.
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Some blood disorders are between benign and malignant (cancerous)—sometimes called precancers—and can develop into cancer. Leukemia is not usually included in the broader blood disorders because it is a blood/bone marrow cancer.


Symptoms of blood disorders vary widely, depending on the blood components affected. Some blood disorders cause few symptoms, while others cause more.


  • Anemia (low red blood cells) can cause fatigue, shortness of breath, or increased heart rate.
  • Thrombocytopenia (low blood platelets) can cause bruising or increased bleeding in the mouth or nose.
  • Hemophilia (poor blood clotting) can also cause increased bleeding, but is known to specifically target muscles and joints without causing serious damage.
  • A blood clot (inappropriate blood clotting) in the arm or leg may cause swelling and pain.


Blood disorders are mostly seen with hematologists – doctors who specialize in diagnosing and treating problems with the blood and/or bone marrow.

Your doctor will examine you and your symptoms to determine the most likely diagnosis. Blood tests are required most of the time. Sometimes blood disorders are discovered during laboratory work for other reasons, such as annual physicals.

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The most commonly used test to diagnose blood disorders is the complete blood count (CBC). The CBC looks at three types of blood cells and determines if any of the blood cells are increased or decreased, or if more than one blood cell is affected. A CBC may also include a blood smear, which provides additional useful information through microscopy.

For bleeding or clotting problems, your doctor may order blood tests for clotting, which include prothrombin time (PT) and partial thromboplastin time (PTT). If the PT or PTT is prolonged (indicating that you bleed more easily than others), further evaluation is needed. Your doctor may order levels of individual clotting factors or evaluate your platelet function.

Blood clots are a little different. To diagnose them, your doctor will need to image the area in question. In the arm or leg, an ultrasound is used to evaluate possible clots. In the lungs or brain, computed tomography (CT) or magnetic resonance imaging (MRI) scans are usually used.

A bone marrow biopsy may be required in some cases to help make a diagnosis. This is usually done by aspirating the marrow from the buttocks.

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Treatment depends on your specific diagnosis. Some chronic blood disorders have no specific treatment but may require treatment during an acute event. E.g:

  • Anemia caused by iron deficiency will be treated with iron supplementation. Beta thalassemia major is an inherited anemia that is treated with monthly blood transfusions.
  • Hemophilia can be treated with clotting factor replacement products, which are used to treat bleeding in an individual, or to prevent bleeding (prophylaxis) when given regularly.
  • Polycythemia vera is treated by phlebotomy—a pint of blood drawn every week until the number of red blood cells drops below a dangerous level.
  • Blood clots can be treated with anticoagulants (blood thinners). Catheter-directed thrombolysis may be required in some cases to dissolve the blockage.
  • Thrombocytosis can be treated with aspirin, or drugs such as hydroxyurea, interferon alfa, or anagrelide (rarely) may be needed.
  • Immune thrombocytopenia can be treated with corticosteroids (such as prednisone) or drugs that raise the platelet count. Removal of the spleen is another treatment that is performed when needed.

It is important to discuss with your doctor the treatment that is best for you and your diagnosis.

VigorTip words

It can be worrying to learn that you or a loved one may have a blood disorder. Sometimes this stress increases when you are referred to a cancer center to see a specialist. This doesn’t necessarily mean your doctor thinks you have cancer. Most hematologists are also trained in oncology (diagnosis and treatment of cancer) and work in clinics alongside oncologists. Hopefully a better understanding of what blood disorders are can alleviate some of your concerns.