What Does a Hematologist Do?

A hematologist specializes in the diagnosis, treatment, and prevention of diseases of the blood. Hematologists focus on direct patient care, while related specialists called hematopathologists use their expertise in blood-related diseases in the lab setting. Hematology is a subspecialty of internal medicine that often overlaps with oncology (the study of cancer).

Hematology-oncology is a combined fellowship program that prepares an internist to diagnose, treat, and manage a wide range of related blood disorders. The focus of their work includes cancerous and noncancerous disorders that affect the individual components of blood (such as white blood cells, red blood cells, or platelets) or the organs that produce them (including the bone marrow and spleen).

Some hematologists will maintain a split practice, seeing both hematology patients as a specialist and internal medicine patients as a primary care provider (PCP).

When Do You Need a Hematologist?

Hematologists work directly with patients who have blood-related disorders. If you have been referred to one, it is because a known or suspected disorder is beyond the skills of your primary care provider and would benefit from an expert whose sole focus is on the blood.

A referral to a hematologist does not necessarily mean that you have cancer. Practically all medical conditions involve hematology to some degree, given that blood tests are commonly used to diagnose or monitor them.

Among the conditions and diseases a hematologist may treat, or participate in treating, are:

• Bleeding disorders like hemophilia
• Red blood cell disorders like anemia, polycythemia vera, or thalassemia
• Blood cancers like leukemia, lymphoma, multiple myeloma, or myelodysplastic syndromes (MDS)
• Obstructive disorders like deep vein thrombosis (DVT) or arterial thromboembolism
• Genetic blood disorders like sickle cell disease
• Autoimmune disorders like autoimmune hemolytic anemia, or idiopathic thrombocytopenic purpura
• Systemic blood infections like sepsis or septic shock
• Treatment for any condition that requires a bone marrow or stem cell transplant

Not everyone with a blood disorder needs a hematologist. If you have blood in the stool, a gastroenterologist may be more appropriate. The same applies to hemorrhagic infections for which an infectious disease specialist may be better suited.

Tests and Procedures

In addition to diagnosing a disease, a hematologist will help you to understand the diagnosis, develop an individualized treatment plan, and coordinate treatment.

Your treatment may include surgery, transfusions, chemotherapy, radiation therapy, or immunotherapy, if needed. The procedures that a hematologist performs may include the following:

• Bone marrow aspiration is the extraction of the liquid part of the bone marrow to diagnose leukemia or lymphoma.
• Bone marrow biopsy is the extraction of the solid core of bone marrow to aid in the diagnosis of leukemia and other cancers. 
• Hemoglobin electrophoresis is a blood test used to confirm sickle cell disease or other inherited disorders affecting red blood cells.
• Human leukocyte antigen (HLA) testing is a blood test used to determine if a bone marrow donor is a good match for a patient.
• Positron emission tomography (PET) is an imaging test that employs a radioactive tracer to locate areas of cancer in the body.
• Lumbar puncture (spinal tap) involves the extraction of cerebrospinal fluid to establish whether there are blood cancer cells in the sample.
• Stem cell and bone marrow transplants may be used to treat certain leukemias, lymphomas, and benign blood disorders.
  

A hematologist may sometimes function as the lead physician managing a patient's care (especially those who specialize in pediatric leukemia) or work as part of a team. These teams can include radiologists, surgeons, radiation oncologists, geneticists, rheumatologists, or other specialists.

Education and Training

Hematology certification requires a four-year medical degree—as either a doctor of medicine (MD) or doctor of osteopathic medicine (DO)—followed by three years of residency to train in a specialized area of practice, such as internal medicine or pediatrics.

Upon completion of the residency, hematologist candidates would undergo two to four years of fellowship to train in a specific subspecialty, such as adult hematology, pediatric hematology/oncology, or hematopathology.

Board certification in hematology is obtained from the American Board of Internal Medicine (ABIM) or the American Society of Clinical Pathology (ASCP). ASCP-certified hematopathologists can often be identified by the abbreviation "MD SH(ASCP)" (Medical Doctor, Specialty Hematology) at the end of their name.

By law, doctors must be licensed by the state in which they practice. Although licensing laws vary by state, all typically require you to graduate from an accredited medical school, successfully complete a specialized residency, and pass the United States Medical Licensing Examination (USMLE).

As with any medical practitioner you may be seeing, it is important to verify the doctor's credentials with either the ABIM or ASCP.

How to Find a Hematologist

To find a certified hematologist, ask your primary care provider for a list of referrals, check with your insurance company for in-network options, or use the American Society of Hematology's online locator.

Questions to Ask Your Hematologist

If you have been referred to a hematologist, it is either because a blood abnormality is at the center of your condition or because you need a medical procedure, such as a stem cell transplant, that would benefit from specialist oversight.

Before meeting with a hematologist for the first time, prepare a list of symptoms that you've been experiencing, including how long you've had them and their severity. It often helps to keep a symptoms journal to record them so you don't forget.

Also, take the time to prepare a list of questions to better understand the nature of your condition and what to expect moving forward. Examples include:

• What do my blood test results mean?
• What tests do you recommend?
• What is involved in testing?
• When can I expect to receive the results?
• How controllable is my condition?
• What are the benefits and risks of treatment?
• What side effects might I expect?
• What would happen if I don't pursue treatment?
• What is the response rate to treatment?
• When would I know if a treatment is successful?

It is also important to check that the hematologist and labs are in-network providers with your insurance company. If not, it may be a good idea to find someone who is, particularly if you suspect that testing or treatments may be costly or extensive.

A Word From Verywell

A hematologist is a highly skilled specialist who is meant to work in collaboration with, and not replace, your primary care physician so that the appropriate care is delivered within the context of your overall health. This is especially important if you have multiple chronic conditions, such as diabetes or liver disease, that may impact treatment decisions.

If you are uncertain about the course of treatment, do not hesitate to seek a second opinion or ask that your medical information be forwarded to another doctor.