What is a blood disorder?

A blood disorder is any condition that keeps one or more parts of the blood from working as expected. Blood disorders are not one type of illness, but instead a family of conditions that can be organized into 5 main categories:

• Red blood cell disorders, which affect cells that carry oxygen.
• White blood cell disorders, which affect cells involved in immune defense.
• Bleeding disorders, which make it harder for the body to stop bleeding normally.
• Blood clotting disorders, which make abnormal clots more likely to form.
• Blood cancers, which begin in blood-forming tissues or blood cells.

Each category affects the blood differently.

What are the main types of blood disorders?

Each of the 5 categories of blood disorders below has its own defining characteristics, yet some symptoms can overlap or be connected to separate health issues. Symptoms alone cannot determine if you have a blood disorder or which one you may have. You should speak to a healthcare professional if you are experiencing any of these symptoms.

How do the symptoms of different blood disorders compare?

Many blood disorders share similar symptoms. Fatigue, for example, can occur when red blood cells do not deliver enough oxygen, but it may also occur with some blood cancers. Bruising or bleeding can point toward a bleeding issue, yet these signs may also appear when other conditions affect platelets or blood cell production. Frequent infections may relate to white blood cell problems, but they are not unique to blood disorders.

The comparison table below shows common blood disorder symptoms. It should not be used to diagnose any condition. A dot means the symptom or sign may appear in that category. It does not show how common, severe, or specific the symptom is.

Where does hemophilia fit among blood disorders?

Hemophilia is a bleeding disorder, not a blood clotting disorder. It is usually inherited and occurs when blood does not clot properly because the level of a clotting factor is low. Clotting factors are proteins in the blood that work together to help stop bleeding.

There are different types of hemophilia. Hemophilia A and B are the most common, while hemophilia C is rare.

Von Willebrand disease is another bleeding disorder, but it involves a different clotting factor protein and is not another name for hemophilia.

Hemophilia is also different from a clotting disorder that causes unwanted blood clots. The similar language can be confusing: clotting factors are part of the process that stops bleeding, but a deficiency in a clotting factor leads to a bleeding problem.

Learn more about Hemophilia and von Willebrand disease explained.

Why are blood disorders so easy to confuse?

Part of the confusion starts with the umbrella term itself: "blood disorder" covers conditions affecting entirely different parts of the blood system—red cells, white cells, clotting proteins, and bone marrow—so the label alone tells you very little about what a specific condition entails.

Blood disorders may also be called blood diseases. The terms are often used in similar ways, but "blood disorder" is used here as a broad umbrella term for different types of conditions that affect the blood.

Additionally, these conditions can share some of the same signs and symptoms. You may notice fatigue, bruising, or frequent infections without knowing the cause.

It may help to think of it this way:

• The umbrella: Blood disorders
• The categories: Red blood cell disorders, white blood cell disorders, bleeding disorders, clotting disorders, and blood cancers
• The branches: Specific conditions within each category, such as hemophilia, anemia, and neutropenia

Names such as “bleeding” and “clotting” disorders can be confusing, too. Both relate to clot formation, but they often involve near-opposite problems. And while blood cancer is a type of blood disorder, not all blood disorders are or become blood cancers.

Prepare for a conversation with your doctor or care team

Knowing that blood disorders fall into different categories and that the symptoms can overlap significantly is a meaningful first step. But pinpointing which category applies to you or someone you care about requires testing and a clinical conversation.

If you're living with a diagnosis or if something about your health has you asking questions, your care team is the right place to bring those concerns. Keep the blood disorders map in mind to help you prepare for a conversation about blood disorders with your doctor.

Download the Doctor Discussion Guide to organize your questions and identify what you would like to discuss.