low blood pressure
Q blood group system
| blood gas monitoring, transcutaneous | The noninvasive measurement or determination of the partial pressure (tension) of oxygen and/or carbon dioxide locally in the capillaries of a tissue by the application to the skin of a special set of electrodes. These electrodes contain photoelectric sensors capable of picking up the specific wavelengths of radiation emitted by oxygenated versus reduced haemoglobin. (12 Dec 1998) |
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| blood glucose | The main sugar that the body makes from the three elements of food--proteins, fats, and carbohydrates--but mostly from carbohydrates. Glucose is the major source of energy for living cells and is carried to each cell through the bloodstream. However, the cells cannot use glucose without the help of insulin. (09 Oct 1997) |
| blood glucose meter | A machine that helps test how much glucose (sugar) is in the blood. A specially coated strip containing a fresh sample of blood is inserted in a machine, when then calculates the correct level of glucose in the blood sample and shows the result in a digital display. Some meters have a memory that can store results from multiple tests. (09 Oct 1997) |
| blood glucose monitoring | A way of testing how much glucose (sugar) is in the blood. A drop of blood, usually taken from the fingertip, is placed on the end of a specially coated strip, called a testing strip. The strip has a chemical on it that makes it change colour according to how much glucose is in the blood. A person can tell if the level of glucose is low, high, or normal in one of two ways. The first is by comparing the colour on the end of the strip to a colour chart that is printed on the side of the test strip container. The second is by inserting the strip into a small machine, called a meter, which reads the strip and shows the level of blood glucose in a digital window display. Blood testing is more accurate than urine testing in monitoring blood glucose levels because it shows what the current level of glucose is, rather than what the level was an hour or so previously. (09 Oct 1997) |
| blood glucose self-monitoring | Self evaluation of whole blood glucose levels outside the clinical laboratory. A digital or battery-operated reflectance meter may be used. It has wide application in controlling unstable insulin-dependent diabetes. (12 Dec 1998) |
| blood group | <haematology> An inherited feature on the surface of the red blood cell. A series of related blood groups make up a blood group system such as the ABO system or the Rh system. Erythrocytic allotypes (or phenotypes) defined by one or more cellular antigenic structural groupings under the control of allelic genes. Blood groups, especially for man, are identified by agglutinins supported by specific human or animal antisera and by lectins extracted from certain plants. See: blood group antigen. (25 Jun 1999) |
| blood group antigen | <haematology, immunology> The set of cell surface antigens found chiefly, but not solely, on blood cells. More than fifteen different blood group systems are recognised in humans. There may be naturally occurring antibodies without immunisation, especially in the case of the ABO system and matching blood groups is important for safe transfusion. In most cases the antigenic determinant resides in the carbohydrate chains of membrane glycoproteins or glycolipids. See: Rhesus, Duffy, Kell, Lewis and MN. (25 Jun 1999) |
| blood group incompatibility | A mismatch between donor and recipient blood. Antibodies present in the recipient's serum are directed against antigens in the donor product. Such a mismatch may result in a transfusion reaction in which, for example, donor blood is haemolyzed. (12 Dec 1998) |
| blood grouping | The classification of blood samples by means of laboratory tests of their agglutination reactions with respect to one or more blood groups. In general, a suspension of erythrocytes to be tested is exposed to a known specific antiserum; agglutination of the erythrocytes indicates that they possess the antigen for which the antiserum is specific. Certain antisera require special testing conditions. (05 Mar 2000) |
| blood grouping and crossmatching | Testing erythrocytes to determine presence or absence of blood-group antigens, testing of serum to determine the presence or absence of antibodies to these antigens, and selecting biocompatible blood by crossmatching samples from the donor against samples from the recipient. Crossmatching is performed prior to transfusion. (12 Dec 1998) |
| blood group substance | Blood group-specific substances A and B, solution of complexes of polysaccharides and amino acids that reduces the titre of anti-A and anti-B isoagglutinins in serum from group O persons; used to render group O blood reasonably safe for transfusion into persons of group A, B, or AB, but does not affect any incompatibility that results from various other factors, such as Rh. (05 Mar 2000) |
| blood haemopathies | A group of disease states which primarily involve the bone marrow and the production blood cells. Examples include polycythaemia vera, leukaemia, myelofibrosis and primary thrombocytopenia. (27 Sep 1997) |
| blood island | An aggregation of splanchnic mesodermal cells on the embryonic yolk sac, with the potentiality of forming vascular endothelium and primitive blood cells. Synonym: blood islet. (05 Mar 2000) |
| blood islet | An aggregation of splanchnic mesodermal cells on the embryonic yolk sac, with the potentiality of forming vascular endothelium and primitive blood cells. Synonym: blood islet. (05 Mar 2000) |
| blood loss, surgical | Loss of blood during surgery. (12 Dec 1998) |