| blood urea nitrogen | Blood urea nitrogen (BUN) is a metabolic by product (in the liver) from the breakdown of blood, muscle and protein. Blood urea nitrogen can be measured from a simple venipuncture specimen. Abnormal elevation in the blood urea nitrogen can indicate renal disease, dehydration, congestive heart failure, gastrointestinal bleeding, starvation, shock or urinary tract obstruction (by tumour or prostate gland). Low BUN level can indicate liver disease, malnutrition or a low protein diet. Normal BUN levels should be between 7 and 20 mg/dl (milligrams per decilitre). (27 Sep 1997) |
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| blood, urinary | Medically called haematuria, blood in the urine can be microscopic or gross. Evaluating haematuria requires consideration of the entire urinary tract. Tests used for the diagnosis of haematuria include the intravenous pyelogram (IVP), cystoscopy, and urine cytology. Management of haematuria depends upon the underlying cause. (12 Dec 1998) |
| blood-vascular system | The heart and the blood vessels by which blood is pumped and circulated through the body. (12 Dec 1998) |
| blood vessel | <anatomy> All the vessels lined with endothelium through which blood circulates. (18 Nov 1997) |
| blood vessel prosthesis | Prosthesis, constructed of either synthetic or biological material, which is used for the repair of injured or diseased blood vessels. (12 Dec 1998) |
| blood vessel prosthesis implantation | Surgical insertion of synthetic or biological material to repair injured or diseased blood vessels. (12 Dec 1998) |
| blood vessels | Any of the tubular vessels conveying the blood (arteries, arterioles, capillaries, venules, and veins). (12 Dec 1998) |
| blood viscosity | The internal resistance of the blood to shear forces. The in vitro measure of whole blood viscosity is of limited clinical utility because it bears little relationship to the actual viscosity within the circulation, but an increase in the viscosity of circulating blood can contribute to morbidity in patients suffering from disorders such as sickle cell anaemia and polycythemia. (12 Dec 1998) |
| blood volume | Volume of circulating blood. It is the sum of the plasma volume and erythrocyte volume. (12 Dec 1998) |
| blood volume determination | Method for determining the circulating blood volume by introducing a known quantity of foreign substance into the blood and determining its concentration some minutes later when thorough mixing has occurred. From these two values the blood volume can be calculated by dividing the quantity of injected material by its concentration in the blood at the time of uniform mixing. Generally expressed as cubic centimeters or liters per kilogram of body weight. (12 Dec 1998) |
| blood volume nomogram | A nomogram used to predict blood volume on the basis of the individual's weight and height. (05 Mar 2000) |
| Bordet-Gengou potato blood agar | Glycerine-potato agar with 25% of blood, used for the isolation of Bordetella pertussis. (05 Mar 2000) |
| buffer value of the blood | The ability of the blood to compensate for additions of acid or alkali without disturbance of the pH. (05 Mar 2000) |
| carbon dioxide blood level | A measure of the bicarbonate level in the blood based on a venipuncture specimen. The serum carbon dioxide is one of the normally reported values in the electrolytes profile. Lower levels of carbon dioxide indicate an acidosis. The normal level is 20 to 29 mEq/L. Lower than normal levels can indicate diabetic ketoacidosis, lactic acidosis, alcoholic ketoacidosis, kidney disease, renal failure, diarrhoea, Addison's disease, ethylene glycol poisoning or methanol poisoning. Greater than normal levels can be seen with excessive vomiting, hyperaldosteronism and Cushing's syndrome. (27 Sep 1997) |
| cardiac blood pool imaging | This noninvasive test uses radioactive tracers to delineate the hearts chambers and major vessels. It may be used to detect a heart attack, heart muscle function and coronary artery disease. The patient receives a radioactive tracer by injection (into a vein) and then the heart is imaged using a gamma camera. The heart is imaged before and after exercise. This test may be used to detect and evaluate atrial septal defect, dilated cardiomyopathy, congestive heart failure, cardiomyopathy, Lyme disease (secondary), mitral stenosis and superior vena cava syndrome. (27 Sep 1997) |