Blood

Hypoxemia (or hypoxaemia in British English) is an abnormally low level of oxygen in the blood.

Leukocytosis is white cells (the leukocyte count) above the normal range in the blood.

A blood type (also called a blood group) is a classification of blood based on the presence and absence of antibodies and also based on the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs).

Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells.

Blood transfusion is generally the process of receiving blood or blood products into one's circulation intravenously.

White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders.

Alkalosis is the result of a process reducing hydrogen ion concentration of arterial blood plasma (alkalemia).

Acidosis is an increased acidity in the blood and other body tissue (i.e. an increased hydrogen ion concentration).

Iron-deficiency anemia, also spelled iron-deficiency anaemia, is anemia caused by a lack of iron.

Reticulocytes are immature red blood cells, typically composing about 1% of the red blood cells in the human body.

In blood, the serum (/ˈsɪərəm/ or /ˈsɪrəm/) is the component that is neither a blood cell (serum does not contain white or red blood cells) nor a clotting factor; it is the blood plasma not including the fibrinogens.

In cell biology, phagocytosis (from Ancient Greek φαγεῖν (phagein) , meaning "to devour", κύτος, (kytos) , meaning "cell", and -osis, meaning "process") is the process by which a cell—often a phagocyte or a protist—engulfs a solid particle to form an internal vesicle known as a phagosome.

Hypovolemia (also hypovolaemia or oligemia) is a state of decreased blood volume; more specifically, decrease in volume of blood plasma.

Bloodletting (or blood-letting) is the withdrawal of blood from a patient to cure or prevent illness and disease.

Neutropenia or neutropaenia, is an abnormally low concentration of neutrophils (a type of white blood cell) in the blood.

Antiserum (plural: antisera) is blood serum containing polyclonal antibodies and is used to pass on passive immunity to many diseases.

Blood fractionation is the process of fractionating whole blood, or separating it into its component parts.

In medicine, when referring to human feces, blood in stool looks different depending on (1) how early it enters the intestines (and thus how much digestive action it has been exposed to) and on (2) how much there is (a little bit, more than a little, or a lot).

Blood lead level (BLL), is a measure of lead in the blood.

In medicine, photopheresis (aka extracorporeal photopheresis or ECP) is a form of apheresis and photodynamic therapy in which blood is treated with a photosensitizing agent and subsequently irradiated with specified wavelengths of light to achieve an effect.

Complement component 4 (C4), in humans, is a protein involved in the intricate complement system, originating from the human leukocyte antigen (HLA) system.