What Is a Hematologist?

A Guide to Hematology

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).

Diseases Treated by a Hematologist
Verywell / Nusha Ashjaee

Conditions and Procedures

Practically all medical conditions involve hematology to some degree, given that blood tests are commonly used to diagnose or monitor them.

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 a radiologist, surgeon, radiation oncologist, geneticist, rheumatologist, or other specialists.

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.
  • Magnetic resonance angiography (MRA) uses a magnetic field and radio waves to produce cross-sectional images of tissues to aid in the diagnosis of stroke and other vascular diseases.
  • Stem cell and bone marrow transplants may be used to treat certain leukemias, lymphomas, and benign blood disorders.

Hematologist-oncologists are also specially trained in the use of chemotherapy drugs and other treatments for blood cancers, including targeted drugs and immunotherapy agents.

Why You May Be Referred to 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.

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

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.

Training and Certification

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.

Based on income data from the 2022 Medscape Physician Compensation Report, a hematologist can expect to earn between what an internist ($264,000) and an oncologist ($411,000) makes.

Appointment Tips

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.

You should also prepare a list of any medications you are taking, whether they be pharmaceutical, over-the-counter, herbal, or alternative. Some of these could potentially affect your blood chemistry or complicate treatment.

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.

Frequently Asked Questions

  • How do I 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 online locator offered by the American Society of Hematology.

  • Where does hematology-oncology fit into cancer care?

    Hematologist-oncologists focus on blood-related cancers. But there are other oncology specialists you may encounter during your care. They include surgical oncologists responsible for any needed surgery and radiation oncologists responsible for delivering radiation therapy.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Masselink LE, Erikson CE, Connell NT, et al. Associations between hematology/oncology fellows' training and mentorship experiences and hematology-only career plansBlood Adv. 2019;3(21):3278–3286. doi:10.1182/bloodadvances.2019000569

  2. American Society of Hematology. Blood disorders.

  3. Medscape. Medscape Physician Compensation Report 2022: Incomes Gain, Pay Gaps Remain.

Additional Reading

By Mary Kugler, RN
Mary Kugler, RN, is a pediatric nurse whose specialty is caring for children with long-term or severe medical problems.