Kettering Glossary

Acid-Fast Bacillus (AFB) Staining (Ziehl-Neelsen) Answer Used for the diagnosis of tuberculosis, tuberculous infections and leprosy. Organisms will appear red against a blue background when stained by this method. Usually takes 2-3 weeks to culture the tubercle bacilli. Results of the AFB stain may indicate the need for the initiation of therapy. Airway Resistance (Raw) Answer Estimated for patients on mechanical ventilation by determining the difference between peak airway pressure and plateau pressure. Used to determine the amount of initial pressure support necessary to overcome airways resistance. Most accurately measured by placing the patient in a Body Plethysmogragh (Body Box) in the Pulmonary Function Lab. Albumin Answer Normal value 3.5-5.0 g/dL. Important in maintaining osmotic pressure of the blood and has primary role in lipid metabolism. Decreased levels are seen in patients with protein malnutrition and severe liver disease. Chronic inflammation, severe acute disease and kidney disease lead to low albumin levels. Severe hypoalbuminemia may result in a loss of fluid from the vascular space and contribute to pulmonary edema. Angiogram Answer Serial X-rays of a blood vessel taken in rapid sequence following injection of a radiopaque substance into a vessel. Used to define the size, shape and patency of various veins and arteries. Can evaluate blood flow to the brain (cerebral), heart (coronary), lungs (pulmonary), kidneys (renal), or liver (hepatic). Anion Gap Answer Normal range is 8-18 mEq/L. The major indication for this test is to identify the cause of a metabolic acidosis. Loss of base results in a normal anion gap while the gain of fixed acids (lactic acidosis) results in an elevated anion gap. Anion gap is also affected by serum albumin levels (rising when albumin does and vice versa).