Glossary: Blood (Hematology) Tests

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Absolute neutrophil count (ANC): The actual number of white blood cells (WBCs) that are neutrophils. It is calculated by multiplying the WBC count times the percent of neutrophils in the differential WBC count. The percent of neutrophils includes both fully mature neutrophils and almost mature neutrophils, also known as “bands”.

Absolute lymphocyte count (ALC): The actual number of white blood cells (WBCs) that are lymphocytes. It is calculated by multiplying the WBC count times the percent of lymphocytes in the differential WBC count.

Complete blood count (CBC): A routine test performed on a small amount of blood. The CBC measures the number of each blood cell type, the size of the red blood cells, the total amount of hemoglobin, and the fraction of the blood made up of red blood cells. It may also be called a blood count.

Hematocrit: A blood test usually part of the CBC. It measures the proportion of the blood containing red blood cells. This measurement depends on the number of red blood cells and their size.

Hemoglobin: This is a measure of the iron-containing pigment, hemoglobin, found in red blood cells. It carries oxygen from the lungs to the tissues in the body. It is part of a CBC.

Leucocytes: All white blood cells (WBC) including neutrophils, lymphocytes, monocytes, esosinophils, and basophils.

Mean Corpuscular Volume (MCV): The measure of the volume or size of the red blood cells.

Mean Corpuscular Hemoglobin Concentration (MCHC): A calculation of the average percentage of hemoglobin in each red blood cell.

Mean Corpuscular Hemoglobin (MCH): A measure of the average amount of hemoglobin in a red blood cell.

Monocytes: Large white blood cells that can become macrophages when they leave the bloodstream to fight inflammation, and dendritic cells that present antigens (proteins to T cells).

Red Blood cells (RBC) Count: Total number of RBC per microliter of blood.

Reticulocytes: These are immature RBC, seen in a healthy response to anemia.

Smudge cells are “ghost cells” with no nuclei seen on a blood smear and most often associated with CLL. A high percent of smudge cells in CLL is associated with longer survival.

White blood cell (WBC) count: The total number of all the leucocytes per microliter of blood.

White blood cell (WBC) differential: A group of tests that includes the following: absolute neutrophil count or % neutrophils, absolute lymphocyte count or % lymphocytes, absolute monocyte count or % monocytes, absolute eosinophil count or % eosinophils, and absolute basophil count or % basophils.

Medical Terminology Based on Lab Results

Anemia: When the body does not have enough healthy red blood cells. Symptoms of anemia can be fatigue, shortness of breath or lightheadedness.

Basophilia: An increase in the number of basophils in the blood. This is rare

Cytopenia: A shortage of one or more blood cell types circulating in the blood. It is also called a low blood count.

Eosinophilia: An increase in the number of eosinophils in the blood, seen with allergies and some rare parasitic infections.’

Leukocytosis. This is where are too many of the total white blood cells or leukocytes in the blood. Infections and leukemia are possible causes.

Leukopenia: A condition in which the number of white blood cells or leukocytes circulating in the blood is greatly reduced below normal. A low number of white blood cells leads to an increased risk of infections.

Lymphocytosis: An increase in the number of lymphocytes, whatever the cause. CLL is one reason for lymphocytosis.

Lymphoproliferation: An increase in the production of lymphocytes or white blood cells. This may occur as a normal response to infection.

Neutrophilia: Too many neutrophils in the blood, mostly commonly from an infection or inflammation, but also from some leukemia.

Neutropenia: Too few neutrophils in the bloodstream. Neutrophils are a type of white blood cell. The reduction of white blood cells leads to an increased risk of infection.

Pancytopenia: A shortage of all types of blood cells — red blood cells, white blood cells, and platelets. This is usually from a problem in the bone marrow.

Thrombocytosis: An increased number of platelets (thrombocytes) in the blood from any cause, cancerous or non-cancerous. It can increase the risk of blood clots.

Thrombocytopenia: A shortage of platelets in the bloodstream. This results in a low platelet count and can result in problems with bleeding and bruising.