Hematologists are healthcare providers who specialize in diagnosing, treating and managing diseases that affect your blood, bone marrow and lymphatic system. Blood diseases may be benign (noncancerous) disorders or malignant (cancerous). Blood disorders and blood cancer may have mild symptoms or be life-threatening.

What is a hematologist?

According to the American College of Physicians, a hematologist is a healthcare provider who specializes in diseases that affect your blood, bone marrow and lymphatic system. Hematology is a sub-specialty of internal medicine.


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What does a hematologist do?

Hematologists diagnose, treat and manage a wide range of diseases that affect your blood cells. Blood diseases may be benign (noncancerous) or malignant (cancerous). Some diseases keep your blood from flowing (blood clots). Other diseases make you bleed more than normal. Blood disorders and blood cancer may have mild symptoms or be life-threatening.

Is a hematologist the same as an oncologist?

No, but a hematologist may also be an oncologist. Oncologists diagnose and treat all kinds of cancer. Hematologists focus on problems with your blood and parts of your body that help produce blood. That said, there’s a natural overlap between hematology and oncology, as many types of cancer start in blood cells in your bone marrow and lymphatic system.

Does hematology mean cancer?

No, seeing a hematologist doesn’t mean you have cancer. Hematologists treat all kinds of blood diseases. You may see a hematologist if your primary care provider recommends you see a specialist because your blood tests show abnormal blood cell count or coagulation levels.


When would I need to see a hematologist?

You may need to see a hematologist because your primary healthcare provider wants a blood specialist to review your blood test results. It’s important to remember that initial blood test results aren’t signs of serious illness.

What are common blood diseases?

We rely on our blood for many things. Red blood cells give our body energy by carrying oxygen to tissues throughout our bodies. White blood cells help our immune system fight infection. Platelets are blood cells that help slow and stop bleeding. Plasma is a liquid that holds your blood cells together.

If you have a blood disease, it means one or more parts of your blood aren’t working as they should. Some blood diseases (disorders) are benign, meaning they aren’t cancer but they’re still serious illnesses.

Benign blood diseases/disorders

A benign blood disease or blood disorder affects your blood but isn’t cancer. Here are some examples:

  • Anemia: This disease happens when you don’t have enough red blood cells to carry oxygen throughout your body. There are many types of anemia, but the most common type is iron-deficiency anemia.
  • Von Willebrand Disease: This is the most common bleeding disorder in the United States.
  • Hemophilia: This is an inherited blood disorder that impairs blood clotting.
  • Sickle cell anemia: This inherited disorder that affects the shape of red cells
  • Thalassemias: Thalassemia is an inherited blood disorder that affects your body’s ability to produce hemoglobin and healthy red blood cells.

Common blood cancers

There are many different blood cancer types. According to the Leukemia & Lymphoma Society, the three most common blood cancers are:

  • Leukemia: Leukemia is the most common blood cancer in the United States and the most common cancer among children and teenagers. The five-year survival rate has quadrupled over the past 40 years.
  • Lymphoma: Lymphoma is cancer of your lymphatic system. The lymphoma survival rate has doubled over the past 40 years.
  • Myeloma:Myeloma is cancer that starts in your bone marrow and affects your plasma cells. More than half of people diagnosed with myeloma are alive five years after diagnosis.

Each blood cancer has many different sub-types.


What education is required to become a hematologist?

All healthcare providers must complete four years in medical school to obtain a medical degree. Healthcare providers who are hematologists have completed the following requirements:

  • They’ve completed a three-year residency: This is graduate medical education that includes patient care. Many hematologists complete residency in internal medicine or pediatrics.
  • They’ve completed a three- to five-year fellowship: This is additional training and education in a specific area of medicine. In this case, healthcare providers have additional training and education in hematology. Some may combine hematology with oncology training.

Typical hematology fellowships

Healthcare providers may specialize in different kinds of hematology, including:

  • Adult hematology: This fellowship type prepares healthcare providers to treat blood disorders, bone marrow disease and lymphatic system diseases that affect adults.
  • Pediatric hematology: As the title implies, this type prepares providers to treat children who have blood diseases.
  • Coagulation: This type refers to diseases that affect blood clotting.
  • Hematology/oncology: This fellowship prepares providers to treat blood disorders and blood cancer.

Once they’ve completed their fellowship training, providers are eligible to obtain board certification from the American Board of Internal Medicine. (The American Board of Pediatrics certifies providers who specialize in pediatric hematology.) All providers must pass the United States Medical Licensing Examination and be licensed by the state in which they’ll practice.

What should I expect from my appointment with my hematologist?

If you have an appointment with a hematologist, it’s because your blood tests show there’s something going on with your blood cells. Your hematologist may have recommended follow-up tests for more information about your blood. At your appointment, your hematologist will:

  • Ask about your overall health.
  • Ask about changes in your body that may be blood disease symptoms.
  • Review your blood test results with you.
  • Explain what they believe caused those results.
  • Discuss what other tests you may need.
  • If they have a diagnosis, they’ll explain your diagnosis and make treatment recommendations.

What are common blood tests?

Your blood consists of many parts. Healthcare providers may order tests that evaluate your blood as whole or different parts of your blood. Here are some common tests a hematologist may order to diagnose a blood disorder or blood cancer:

  • Complete blood count (CBC):This basic blood test evaluates your red blood cells, white blood cells and platelets.
  • Blood differential test: This test counts the numbers of each type of white blood cell. Providers may do this test when they do a complete blood count.
  • Prothrombin time test (PTT): This test measures how quickly your blood forms clots.
  • Reticulocyte count:This test measures the number of young blood cells (reticulocytes) in your blood.
  • Peripheral blood smear (PBS):Providers use this process to examine your red and white blood cells and platelets under a microscope.

What are blood tests for cancer?

Blood tests for cancer are one of many tools healthcare providers use to diagnose and manage cancer. A hematologist may use blood tests to:

  • Look for chemicals and proteins in your blood that might indicate cancer.
  • Check on blood cell levels.
  • Evaluate your overall health.

If you have blood cancer, you may have additional blood tests. Your hematologist may use these test results to:

  • Help to stage cancer. When healthcare providers stage cancer, they focus on cancer tumor size and location. They use that information to place the cancer in specific category or stage labeled with numbers and letters. Staging cancer lays the foundation for cancer treatment.
  • Decide on cancer treatment options.
  • Check to see if the disease is improving with time and/or treatment, or if it’s getting worse.
  • Determine if cancer has come back (recurrence).

What questions should I ask my hematologist?

You’re probably seeing your hematologist because you had blood tests that show something is happening in your blood. Here are a few questions to consider:

  • What did my blood tests show?
  • What do those results mean?
  • What’s wrong with me? What condition do I have?
  • Is this condition serious?
  • What causes this condition?
  • Are there any symptoms I need to watch for?
  • What do I need to do if I notice those symptoms?
  • Will I need more blood tests or other tests?
  • What do you want to find out from the tests?
  • When will I get my test results?
  • Will I need more tests later?
  • What treatment do you recommend for me and why?
  • When will I start treatment and how long will it last?
  • What do I need to know about the medicine you’re prescribing?
  • Are there any side effects?
  • What are the risks and benefits of this treatment?
  • Are there other treatment options?

A note from Cleveland Clinic

If you’re seeing a hematologist, it’s because tests show your blood cells, bone marrow or lymphatic system may not be working as well as it should. You may feel apprehensive about seeing a healthcare provider who specializes in blood diseases, including blood cancer. If you have questions about your test results, ask your hematologist to review your results and what they’ll do to determine what caused the results. They’ll be happy to answer your questions and explain next steps.

Medically Reviewed

Last reviewed on 07/19/2022.

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