Key Terms

ABO system

categorization of blood into four main types—A, B, AB, and O—based on the different antigens on the surface of red blood cells

acute hemolytic reaction

transfusion reaction due to an ABO mismatch, which can lead to serious signs and symptoms, including low blood pressure and shock, hemoglobinuria, nausea, vomiting, pain, chills, and fever

alcoholic thrombocytopenia

condition in which excessive alcohol consumption results in decreased platelet count in the blood, leading to decreased clotting mechanisms and increasing the risk for bleeding and bruising

allergic reaction

transfusion reaction due to an allergy to one or more proteins present in donor blood; symptoms may range from mild irritation to serious anaphylaxis

anemia

medical condition characterized by deficient production of red blood cells or of hemoglobin

blood transfusion

medical procedure involving the transfer of blood or its components from one individual (donor) to another individual (recipient)

bone marrow aspiration

test to verify the presence of sickle cell anemia by measuring the production of red blood cells in the bone marrow

coagulation

process of a liquid (e.g., blood) changing into a semi-solid or solid condition

complete blood count (CBC)

measurement of the number of red blood cells, white blood cells, and platelets in a sample of blood

D-dimer test

test that measures a protein in the blood produced after the breakdown of blood clots

dactylitis

hand-foot syndrome manifesting as swelling (edema) and pain of the hands and feet during a sickle cell crisis

deep vein thrombosis (DVT)

medical condition marked by the formation of blood clots within deep veins in the legs

delayed hemolytic reaction

transfusion reaction that happens more than 15 minutes after transfusion, with similar symptoms to other types of reactions

disseminated intravascular coagulation (DIC)

acquired disorder that activates the clotting cascade, using up all the clotting factors and resulting in a mix of clotting and bleeding

embolism

blood clot that has come loose and can travel through the body

erythropoiesis

hemoglobin production

erythropoietin (EPO)

hormone made in the kidneys that stimulates bone marrow to produce red blood cells

factor V Leiden mutation

disorder caused by a mutation to the F5 gene, which prevents normal production of the factor V needed for clotting

febrile nonhemolytic reaction

most prevalent type of transfusion reaction, usually manifesting as an increase of 1° in temperature over baseline

fibrinolysis

breaking down of blood clots after they form

folate-deficiency anemia

type of anemia in which inadequate levels of the vitamin folate within the body cause low levels of red blood cells and hemoglobin; also called megaloblastic anemia

hematopoietic system

body structures responsible for the formation of blood cells

hemoglobin (Hb)

protein in red blood cells that is key to the transport of oxygen from the lungs to cells and tissues

hemoglobin electrophoresis

test to diagnose sickle cell anemia by distinguishing different forms of hemoglobin to detect the form and characteristics of sickle-shaped red blood cells

hemoglobin solubility test

quick screening method to detect sickle hemoglobin by mixing blood with a reducing agent to inactivate hemoglobin and form characteristic crystals

hemoglobinuria

breakdown of hemoglobin in the urine

hemogram

detailed analysis of a blood sample that examines not only the quantity of red blood cells, white blood cells, and platelets but also their size, color, and percentage of iron

hemolysis

destruction of red blood cells

hemostasis

physiological process that prevents and controls bleeding

heparin-induced thrombocytopenia (HIT)

immune-mediated side effect caused by prolonged use of anticoagulants like heparin

idiopathic thrombocytopenic purpura (ITP)

autoimmune condition marked by an abrupt and significant drop in platelet count, leading to increased risks of bleeding and anemia; more frequently referred to as immune thrombocytopenia

international normalized ratio (INR)

standard measurement of prothrombin time that is used across different laboratories

intravenous immunoglobulin infusion therapy (IVIG)

intravenous administration of antibodies collected from multiple donors to maintain a controlled immune response that fights infection without further injuring tissues damaged by idiopathic thrombocytopenic purpura

intrinsic factor

essential protein needed for the absorption of vitamin B₁₂ by the small intestine

iron chelation therapy

therapy in which medications bind to excess iron in the bloodstream, creating a compound that can then be expelled from the body through excretion

iron-deficiency anemia

anemia due to inadequate levels of iron

jaundice

yellowing of the skin and sclera

mean corpuscular hemoglobin concentration (MCHC)

concentration of hemoglobin in a red blood cell

mean corpuscular volume (MCV)

average size of red blood cells in a sample

neutropenia

medical condition marked by abnormally low levels of neutrophils

neutrophil

type of white blood cell that helps fight against bacteria and fungi

pancytopenia

reduction in platelets, red blood cells, and white blood cells

partial thromboplastic time (PTT)

measurement of the time it takes blood to clot, based on the intrinsic clotting cascade

peripheral blood smear

test enabling analysis of red blood cell shape and condition for diagnostic purposes

pernicious anemia

anemia due to inadequate levels of vitamin B₁₂; also referred to as vitamin B₁₂ malabsorption anemia

plasmapheresis

removal, treatment, and return or exchange of blood and blood products

platelet aggregation

clumping together of platelets in the blood

polycythemia

hematologic condition marked by an abnormal increase in the number of red blood cells

polycythemia vera

type of polycythemia that originates from the bone marrow and is caused by a genetic mutation; also called primary polycythemia

prothrombin G20210A mutation

disorder caused by a mutation to the prothrombin (F2) gene, which results in higher levels of the clotting factor prothrombin

prothrombin time (PT)

measurement of the time it takes for blood to clot, based on extrinsic clotting factors

pulmonary embolism (PE)

blood clot from deep vein thrombosis that migrates through the circulatory system and lodges within a pulmonary artery in a lung, blocking off oxygen

purpura

large, discolored, purple areas that may be seen throughout the body, due to internal bleeding

reticulocyte count

measures the number of young RBCs in a blood sample

reverse precautions

measures to avoid introducing additional pathogens to the patient

secondary polycythemia

type of polycythemia caused when erythropoietin stimulation occurs as an adaptive reaction to other conditions

septic reaction

transfusion reaction resulting from blood products that have been incorrectly stored and thus become contaminated

sequential compression device (SCD)

external sleeves that wrap around a patient’s legs and inflate and deflate to promote blood flow

sickle cell anemia (SCA)

one of the many types of sickle cell diseases that causes severe anemia

sickle cell disease

inherited blood disorder caused by abnormal hemoglobin production that forms red blood cells into crescent-shaped “sickles”

thalassemia

group of hereditary blood disorders that affect the hemoglobin genes, leading to decreased erythropoiesis

therapeutic phlebotomy

removal of excess red blood cells by reducing overall blood volume

thrombocytopenia

hematologic condition characterized by decreased platelets in the bloodstream, significantly impairing the blood’s ability to clot effectively; also called low platelet count syndrome

thrombopoietin

protein released by the liver

thrombotic disorder

condition that interferes with hemostasis, or blood clotting

thrombus

clot that forms inside a blood vessel

total bilirubin test

blood test that measures the amount of bilirubin in a patient’s system, indicating liver strain from the accelerated turnover of RBC cells caused by sickle cell anemia

transfusion-associated circulatory overload (TACO)

transfusion reaction that happens when fluid volumes have exceeded expectations; symptoms include shortness of breath, coarse lung sounds, and possible edema formation

transfusion-related acute lung injury (TRALI)

transfusion reaction manifesting as acute respiratory distress syndrome due to an immune response between donor antibodies and antigens in a recipient

vaso-occlusive crisis

result of sickle cell anemia caused by constricted blood vessels and hypoxemia; also known as a pain crisis and sickle cell crisis