Dictionary

blood pressure, low See hypotension.

blood sugar, high See hyperglycemia.

blood sugar, low See hypoglycemia.

blood test A test that requires a sample of blood. Some blood tests require only a finger stick, and others require a venipuncture (blood taken from a vein) or blood withdrawn from an artery.

blood thinner An anticoagulant agent; a medication that works against coagulating process of blood.

blood titer A blood test that tests for the level, or amount (titer), of something in the blood. For example, a strep titer looks for the level of streptococcus antibodies in the blood.

blood transfusion The transfer of blood or blood components from one person (the donor) into the bloodstream of another person (the recipient). Blood transfusion may be done as a lifesaving maneuver to replace blood cells or blood products lost through bleeding or due to depression of the bone marrow. Transfusion of one’s own blood (autologous)…

blood urea nitrogen A measure of the urea level in blood. Abbreviated BUN. Diseases that compromise the function of the kidney frequently lead to increased BUN levels.

blood, urinary See blood in the urine.

blood–brain barrier A protective network of blood vessels and cells that filters blood flowing to the brain. The blood–brain barrier normally prevents infectious agents and foreign substances from getting into the brain. Medications designed to work within the brain and spinal fluid must cross the blood–brain barrier to be effective.

bloody nose See nosebleed.

bloody show Literally, the appearance of blood, a classic sign of impending labor. The bloody show consists of blood-tinged mucus created by extrusion and passage of the mucous plug that filled the cervical canal during pregnancy.