We developed this glossary to familiarize you with some of the complicated terms you may hear from a healthcare provider.

ANC (absolute neutrophil count): A measure of the actual number of mature neutrophils in a given volume of blood.

Anemia: A condition in which the number of red blood cells is below normal, resulting in fatigue or weakness.

Antibiotics: Drugs used to treat infection.

Antibodies: Proteins produced by plasma cells in response to foreign substances in the body.

Biopsy: The removal and examination of a small piece of tissue from the body to determine a precise diagnosis.

Blast cells: Immature blood cells.

Bone marrow: The soft, sponge-like tissue in the center of bones that produces white blood cells, red blood cells, and platelets.

Calcium: A mineral found in teeth, bones, and other body tissues.

Cancer: A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread through the bloodstream to other parts of the body.

Chemotherapy: Treatment of cancer or related diseases with chemical agents.

Clinical trial: A research study designed to evaluate new methods of screening, prevention, diagnosis, or treatment.

CT (Computed Tomography) scan: A test using X-rays to create cross sections of organs and structures inside the body, used to detect diseases, cancers or status of bone or tissue damage.

Cytopenia: A deficiency of cells in the blood.

Eosinophil: Type of white blood cell that kills parasites and plays a role in allergic reactions.

Erythrocyte: A mature red blood cell.

Granulocyte: A term for any of the white blood cell types that have granules containing enzymes to help fight infection: neutrophils, eosinophils, and basophils.

Hematocrit: Percent of the total blood volume that is made up of red blood cells.

Hematologist: A doctor who specializes in treating blood diseases.

Immune system: The complex group of organs and cells that defends the body against infection and disease.

Monocyte: A type of white blood cell that matures into a macrophage, which plays a role in immune responses.

MRI (Magnetic Resonance Imaging): A test that uses a powerful magnet linked to a computer to create pictures of tissues inside the body.

Neutrophil: The most numerous type of white blood cell, important for helping the body fight infections.

Oncologist: A doctor who specializes in treating cancer.

Packed RBCs (pRBCs): A concentrated blood product in which most of the plasma, the fluid part of blood, is removed.

Plasma cells: Special white blood cells that produce antibodies.

Platelets: The smallest cells in the blood, essential for controlling bleeding. Also called thrombocytes.

Radiation therapy: Therapy using high-energy radiation from X-rays and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy) or from radioactive materials that are placed in or near the tumor (internal radiation therapy).

Red blood cells (RBCs): Cells that carry oxygen to your tissues.

Remission: Shrinkage or disappearance of cancer. A remission may be complete (CR) or partial (PR).

Staging: A classification of the severity and extent of cancer within the body.

Stem cells: Cells in the bone marrow that develop into either red blood cells, white blood cells, or platelets.

Systemic therapy: Treatment that uses medicines that affect cells throughout the body.

Thrombocytopenia: A condition in which the number of platelets, or thrombocytes, is below normal, resulting in the tendency to bruise and bleed more easily.

Transfusion: Process by which blood or one of its components is delivered directly into the bloodstream.

Tumor: An abnormal mass of tissue that results from excessive cell division.

White blood cells (WBCs): Cells that help the body fight infection and disease.