A hematologist is a medical doctor who specializes in the diagnosis, treatment, and management of disorders affecting the blood, bone marrow, and lymphatic system. These specialists focus on the cellular components of blood—red cells, white cells, and platelets—and the plasma that carries them. Hematology addresses a wide spectrum of health issues, including common, non-cancerous conditions and complex malignancies. A referral usually follows the discovery of an abnormal result on a routine blood test or the presence of persistent, unexplained physical symptoms.
Common Symptoms That Prompt a Referral
A primary care physician often initiates a referral when a patient reports persistent, non-specific symptoms suggesting an underlying blood issue. Frequent complaints include unexplained or prolonged fatigue and generalized weakness that does not improve with rest. This may be accompanied by paleness or shortness of breath, indicating insufficient oxygen delivery due to a red blood cell problem.
Issues with blood clotting are another common sign, manifesting as excessive or easy bruising, prolonged nosebleeds, or heavy menstrual bleeding. These symptoms suggest a potential problem with the number or function of platelets or the proteins involved in coagulation. Conversely, unexplained swelling or pain in the limbs, which could signal an abnormal internal clot, also warrants investigation.
Problems with the immune system may also lead to a referral, especially if a patient experiences frequent or recurrent infections, high fevers, or drenching night sweats. These findings can point to an issue with white blood cells, the body’s main infection fighters. Additionally, unexplained enlargement of the lymph nodes or an enlarged spleen can indicate an underlying disorder in the lymphatic system.
Categories of Conditions Treated by Hematologists
Hematologists manage a wide array of conditions, generally grouped into three major categories based on the affected blood component.
Red Blood Cell Disorders
This group involves disorders of the red blood cells, which transport oxygen throughout the body. The most common condition is anemia, stemming from insufficient production (like iron-deficiency or vitamin B12-deficiency anemia) or increased destruction of red cells. More complex red blood cell disorders include inherited conditions such as sickle cell disease, where a genetic mutation causes red cells to become rigid and crescent-shaped, leading to blockages. Another inherited condition is thalassemia, which results in the production of abnormal hemoglobin.
Bleeding and Clotting Disorders
This category involves issues with the body’s ability to control bleeding and clotting. Bleeding disorders occur when the blood does not clot effectively, such as in hemophilia (deficiency in clotting factors) or Von Willebrand disease. Conversely, thrombotic disorders involve blood clotting too easily or inappropriately. This includes conditions like Deep Vein Thrombosis (DVT) and hypercoagulable states, which are inherited or acquired tendencies to form clots, often requiring long-term medication.
Hematologic Malignancies
These are cancers that begin in the blood-forming tissues.
- Leukemia is a cancer of the blood and bone marrow, characterized by the overproduction of abnormal white blood cells.
- Lymphoma is a cancer that develops in the lymphatic system, affecting lymphocytes, with two main types being Hodgkin and Non-Hodgkin lymphoma.
- Multiple myeloma is a cancer of the plasma cells, which are specialized white blood cells primarily found in the bone marrow.
Diagnostic Procedures Used in Hematology
To accurately identify the cause of symptoms or abnormal test results, a hematologist employs a range of diagnostic procedures. The most fundamental test is the Complete Blood Count (CBC), which provides a detailed snapshot of the cells circulating in the blood. This test measures the number of red blood cells, white blood cells, and platelets, along with other parameters like hemoglobin concentration and cell size.
Following the CBC, a peripheral blood smear is often performed, where a drop of blood is examined under a microscope. This allows the specialist to visually inspect the size, shape, and maturity of the cells, which can reveal subtle abnormalities. Specialized blood tests are also conducted to assess the blood’s clotting ability, including the Prothrombin Time (PT) and the Activated Partial Thromboplastin Time (aPTT).
When blood tests are insufficient, more involved procedures are necessary. A bone marrow aspiration and biopsy is a common procedure used to evaluate the factory where blood cells are produced. This involves collecting a small sample of the liquid marrow and a piece of the solid bone tissue, typically from the hip bone, for microscopic analysis. The samples help determine if the bone marrow is producing blood cells correctly and can detect the presence of cancerous or abnormal cells.
Advanced techniques like flow cytometry may also be used. This involves passing cells one at a time through a laser to analyze their surface markers and internal properties. This technique is particularly useful for precisely identifying the specific type of abnormal cells in cases of leukemia or lymphoma.