| 释义 |
DictionarySeeTLCMedicalSeeCENTRAL VENOUS CATHETER: A tunneled central venous catheter is inserted through subcutaneous tissue in the chest wall into the jugular or subclavian vein CENTRAL VENOUS CATHETER (SUBCLAVIAN)central venous catheterA catheter inserted into the superior vena cava to permit intermittent or continuous monitoring of central venous pressure, to administer fluids, medications or nutrition, or to facilitate obtaining blood samples for chemical analysis. See: illustrationPatient careHealth care professionals must use caution to prevent life-threatening complications when inserting and maintaining a central line. The subclavian approach to the placement of a central line is preferred, because femoral placements may be complicated by deep venous thrombosis, and internal jugular sites carry an increased risk of infection. Sterile technique is a requirement during insertion. The skin should be prepared with chlorhexidine-gluconate (2%) or povidone-iodine. Ultrasound guidance improves the likelihood of entering the desired vein without injury to neighboring structures. With or without radiological guidance, the best results are obtained by practitioners who perform the procedure frequently. After the catheter is inserted, it should be firmly sewn to the skin to keep it from migrating in and out of the insertion site. An antibiotic impregnated patch covered by a sterile dressing should be placed at the insertion site. The catheter should be manipulated as infrequently as possible during its use. Dressing changes are carried out using sterile technique. IV tubing and solutions and injection caps also should be changed as required by the agency’s protocol. Health care professionals are responsible for preventing, assessing for, and managing central venous therapy complications (e.g., air embolism; cardiac tamponade; chylothorax, hemothorax, hydrothorax, or pneumothorax; local and systemic infections; and thrombosis). Documentation should include preprocedure and postprocedure physical assessment of the patient, catheter type and size, insertion site location, x-ray confirmation of the placement, catheter insertion distance (in centimeters), and the patient’s tolerance of the procedure. Maintenance care procedures also should be fully documented. The site should be carefully inspected for inflammation, and any drainage should be cultured. When catheter-related infections are suspected, the catheter tip provides valuable information about infection sources in cases of sepsis. The tip should be cut off with sterile scissors and dropped directly into a sterile specimen container. illustrationcondom catheterA specially designed condom that includes a collection tube attached to the distal end. The tubing carries urine to a collecting bag. Its use prevents men with urinary incontinence from soiling clothes or bed linens. CAUTION!Continual use of this device may excoriate the skin of the penis. See: Catheter: External Condomdouble-channel catheterA catheter providing for inflow and outflow. elbowed catheterProstatic catheter.eustachian catheterA catheter passed into the eustachian tube through the nasal passages to ventilate the middle ear.female catheterA catheter about 5 in (12.7 cm) long, used to pass into a woman's bladder.Foley catheter See: Foley catheterglide catheterA catheter inserted into the ureter to remove impacted kidney stones. A lubricated wire is advanced past the obstructing stone. The glide catheter is mounted on the wire, moved toward the kidney beyond the stone, and used to snare and retrieve the stone. guide catheterA catheter that makes it easier to enter that vessel with other devices or instruments. Guide catheters are used to facilitate the placement of lasers, stents, and balloons for angioplasty. heparin-bonded catheterA pulmonary artery catheter with a heparin coating to reduce the risk of thrombus formation.Hickman catheter See: Hickman catheterimpregnated catheterA catheter coated with a medication to prevent complications of prolonged insertion in the body. Commonly used coatings include antibiotics and antiseptics. indwelling catheterAny catheter that is allowed to remain in place in a vein, artery, or body cavity.indwelling pleural catheterPleural catheter.intra-aortic catheter See: intra-aortic balloon counterpulsationintrauterine pressure catheter Abbreviation: IUPC
A catheter inserted into the uterus of a woman during labor, when labor is protracted, arrested, or when the force of uterine contractions are difficult to monitor indirectly. intravenous catheterA catheter inserted into a vein to administer fluids or medications or to measure pressure.Karman catheter See: Karman cathetermale catheterA catheter 12 to 13 in (30.5 to 33 cm) long, used to pass into a man's bladder.pacing catheterA catheter inserted most commonly into the right side of the heart via the brachial, femoral, internal jugular, or subclavian vein for temporary pacing of the heart. The pacing wires or leads provide the electrical stimulus from an external source (a pulse generator). peripherally inserted central venous catheter Abbreviation: PICC, PICC line
A soft, flexible central venous catheter, inserted in a vein in the arm and advanced until the tip is positioned in the axillary, subclavian, or brachiocephalic vein. It may also be advanced into the superior vena cava. A PICC is commonly used for prolonged antibiotic therapy, total parenteral nutrition, continuous opioid infusion, or intermittent chemotherapy. pharyngeal suction catheterA rigid catheter used to suction the pharynx during direct visualization. Synonym: Yankauer suction catheterpleural catheterA small chest catheter inserted between the parietal and visceral pleura and used to drain recurrent pleural effusions, e.g., in patients with cancer. Synonym: indwelling pleural catheterpresternal catheterA catheter used for peritoneal dialysis that exits the chest instead of the lower abdomen. It is made of two silicone rubber tubes joined at the implantation site by a titanium connector that links its abdominal and presternal parts. prostatic catheterA catheter, 15 to 16 in (38 to 40.6 cm) long, with a short elbowed tip designed to pass prostatic obstruction. Synonym: elbowed catheterpulmonary artery catheterA catheter inserted into the pulmonary artery to measure pulmonary artery pressures, pulmonary capillary wedge pressure, and, indirectly, left atrial pressure and cardiac output. self-retaining catheterA bladder catheter designed to remain in place (e.g., a Foley catheter). SUPRAPUBIC CATHETER: used to drain urinesuprapubic catheterA catheter that permits direct urinary drainage from the bladder through the lower abdominal wall from a surgically fashioned opening located just above the pubic symphysis. Suprapubic urinary diversion is typically but not exclusively used as a temporary means of decompressing the bladder when the urethra is obstructed, e.g., in children with congenital deformities of the penis or urethra, or in adults with bladder outlet obstruction. When it is used for this purpose, it is considered a bridge before definitive surgery. See: suprapubic aspiration of urine; illustrationPatient careThe nurse observes for hemorrhage or prolonged hematuria and signs of local or systemic infection. Aseptic technique is used during dressing or equipment changes. Bladder irrigation is performed as prescribed. Medications, e.g., analgesics, antispasmodics, and bowel stimulants, are administered as prescribed. The patient's ability to micturate is evaluated. Intake and output are monitored and recorded. Fluids are forced unless otherwise restricted to ensure passage of dilute urine. Swan-Ganz catheter See: Swan-Ganz catheterTenckhoff peritoneal catheter See: Tenckhoff peritoneal cathetertriple-lumen catheter Abbreviation: TLC
A central catheter containing three separate channels or passageways.tunneled central venous catheterAn intravenous catheter inserted into the subclavian or internal jugular vein and then advanced into the right atrium or superior vena cava. The proximal end is tunneled subcutaneously from the insertion site and brought out through the skin at an exit site below the nipple line. Commonly used tunneled catheters include the Hickman and Broviac catheters. umbilical vein catheterA catheter placed in the umbilical vein of an infant to facilitate administration of medicines parenterally or to do an exchange transfusion.vertebrated catheterA catheter in sections to be fitted together so that it is flexible.winged catheterA catheter with little flaps at each side of the beak to help retain it in the bladder.Word catheterA rubber catheter with an inflatable balloon at its end, used to treat cysts or abscesses, e.g., Bartholin gland cysts in the vulva.Yankauer suction catheter See: Yankauer suction catheter
triple-lumen catheter Abbreviation: TLC
A central catheter containing three separate channels or passageways.See also: catheter
chromatography (kro?ma-tog'ra-fe) [ chrom- + -graphy] The separation of two or more chemical compounds in a liquid or gaseous mixture by their removal at different rates based on differential solubility and adsorption. This separation is often accomplished by letting the chemicals percolate through a column of a powdered adsorbent or by passing them across the surface of an adsorbent paper, among other techniques.chromatographic (-mat?o-graf'ik), adjectiveadsorption chromatographyChromatography accomplished by applying the test material to one end of a sheet or column containing a solid. As the material moves, the various constituents adhere to the surface of the particles of the solid at different distances from the starting point according to their chemical characteristics. column chromatographyA form of adsorption chromatography in which the adsorptive material is packed into a column.gas chromatographyAn analytical technique in which a sample is separated into its component parts between a gaseous mobile phase and a chemically active stationary phase.gas-liquid chromatography Abbreviation: GLC
Chromatography in which a gas moves over a liquid, and chemical substances are separated on the liquid by their different adsorption rates.gel filtration chromatographyA type of column chromatography in which chemicals are separated via pores according to their molecular size. high-performance liquid chromatography Abbreviation: HPLC
Application of high pressure to liquid chromatography technique to increase separation speed and enhance resolution. Synonym: high pressure liquid chromatographyhigh pressure liquid chromatographyHigh-performance liquid chromatography.paper chromatographyChromatography in which paper strips are used as the porous solid medium.partition chromatographyChromatography in which substances in solution are separated by being exposed to two immiscible solvents. The immobile solvent is located between the spaces of an inert material such as starch, cellulose, or silica. The substances move with the mobile solvent as it passes down the column at a rate governed by their partition coefficient. thin-layer chromatography Abbreviation: TLC
Chromatography involving the differential adsorption of substances as they pass through a thin layer or sheet of cellulose or some other inert compound.
thin-layer chromatography Abbreviation: TLC
Chromatography involving the differential adsorption of substances as they pass through a thin layer or sheet of cellulose or some other inert compound.See also: chromatography
count (kownt) 1. The number of units in a sample or object.2. To enumerate. absolute granulocyte count Abbreviation: AGC
The total number of neutrophils, basophils, and eosinophils in a specimen of blood.absolute neutrophil count Abbreviation: ANC
The actual number of neutrophils in a cubic millimeter of blood. The approximate normal range is 3000 to 6000 cells/mm3. This figure is measured before and after drugs are given that may lower neutrophil counts, such as those used in cancer chemotherapy. Generally, chemotherapy is not given unless the patient's ANC is greater than 1000. Patients with an ANC of less than 500 cells/mm3 are at high risk for infection. See: neutrophilCAUTION!The development of fever in a patient with neutropenia secondary to chemotherapy is an indication for urgent medical evaluation and prompt institution of broad-spectrum antibiotics. absolute phagocyte count Abbreviation: APC
The number of phagocytes (neutrophils and monocytes-macrophages) in a cubic millimeter of blood. The APC is the sum of the neutrophils (segs and bands), monocytes, and macrophages times one hundredth (1/100) of the white blood cell count. See: absolute neutrophil count; blood countblood countThe number of red cells and leukocytes per microliter (µl) of whole blood. Normally, the number of erythrocytes in men averages 5 million/µl; in women, 4.5 million/µl. Prolonged exposure to high altitude increases the number. Leukocytes average 5000 to 10,000/µl. Platelets range from 140,000 to 400,000/µl. Hemoglobin (12 to 18 g/100 ml) and hematocrit (38% to 48%) are determined from samples of whole blood. complete blood count Abbreviation: CBC
A laboratory evaluation of all the cells that circulate in the blood, including the number and the hemoglobin content of red blood cells, the white blood cells (and their subtypes), and platelets. The typical CBC provides assessments of size and shape of red blood cells and platelets as well. Patient careThe CBC is among the most common blood tests performed in the clinical laboratory and aids in the diagnosis of anemia and erythrocytosis, bleeding and the repletion of blood cells by transfusion, thrombocytopenia and thrombocytosis, and infections and leukemias. Blood is obtained for the test from venipuncture or aspiration from an indwelling vascular access or port. It is taken to the laboratory in a tube that contains the anticoagulant ethylenediaminetetraacetic acid (EDTA). differential blood countThe number and type of white blood cells as determined by microscopic examination of a thin layer of blood on a glass slide stained to show the shape of the various cells. The number and variety of white cells in a sample of a given size are obtained. Even though the red cells are not counted by this method, their shape, size, and color can be evaluated. Some blood diseases and inflammatory conditions may be recognized in this way. In a differential count, the varieties of the leukocytes and their percentages normally should be: neutrophils (segmented), 40% to 60%; eosinophils, 1% to 3%; basophils, 0.5% to 1%; lymphocytes, 20% to 40%; monocytes, 4% to 8%. pollen countThe concentration of grains of pollen found in the atmosphere on a given day in a specific location. The measurement is used by allergy sufferers to forecast the likelihood they will have allergic symptoms, e.g., sneezing, sniffling, or wheezing. surgical countCounting the exact number of sponges, instruments, and other materials before, during, and after an operation in order to reduce the likelihood of leaving an object inside a body cavity. total lymphocyte count Abbreviation: TLC
The number of lymphocytes in a specimen of blood. The count may be increased in clonal diseases such as chronic lymphocytic leukemia or decreased in diseases such as AIDS. In AIDS, decreases in the total lymphocyte count usually reflect a marked decline in the number of helper T4 cells.
total lymphocyte count Abbreviation: TLC
The number of lymphocytes in a specimen of blood. The count may be increased in clonal diseases such as chronic lymphocytic leukemia or decreased in diseases such as AIDS. In AIDS, decreases in the total lymphocyte count usually reflect a marked decline in the number of helper T4 cells. See also: countTLC Abbreviation for total lung capacity. ">TLC through subcutaneous tissue in the chest wall into the jugular or subclavian vein" href="javascript:eml2('davisTab', 'c17.jpg')"> CENTRAL VENOUS CATHETER: A tunneled central venous catheter is inserted through subcutaneous tissue in the chest wall into the jugular or subclavian veinCENTRAL VENOUS CATHETER (SUBCLAVIAN)central venous catheterA catheter inserted into the superior vena cava to permit intermittent or continuous monitoring of central venous pressure, to administer fluids, medications or nutrition, or to facilitate obtaining blood samples for chemical analysis. See: illustrationPatient careHealth care professionals must use caution to prevent life-threatening complications when inserting and maintaining a central line. The subclavian approach to the placement of a central line is preferred, because femoral placements may be complicated by deep venous thrombosis, and internal jugular sites carry an increased risk of infection. Sterile technique is a requirement during insertion. The skin should be prepared with chlorhexidine-gluconate (2%) or povidone-iodine. Ultrasound guidance improves the likelihood of entering the desired vein without injury to neighboring structures. With or without radiological guidance, the best results are obtained by practitioners who perform the procedure frequently. After the catheter is inserted, it should be firmly sewn to the skin to keep it from migrating in and out of the insertion site. An antibiotic impregnated patch covered by a sterile dressing should be placed at the insertion site. The catheter should be manipulated as infrequently as possible during its use. Dressing changes are carried out using sterile technique. IV tubing and solutions and injection caps also should be changed as required by the agency’s protocol. Health care professionals are responsible for preventing, assessing for, and managing central venous therapy complications (e.g., air embolism; cardiac tamponade; chylothorax, hemothorax, hydrothorax, or pneumothorax; local and systemic infections; and thrombosis). Documentation should include preprocedure and postprocedure physical assessment of the patient, catheter type and size, insertion site location, x-ray confirmation of the placement, catheter insertion distance (in centimeters), and the patient’s tolerance of the procedure. Maintenance care procedures also should be fully documented. The site should be carefully inspected for inflammation, and any drainage should be cultured. When catheter-related infections are suspected, the catheter tip provides valuable information about infection sources in cases of sepsis. The tip should be cut off with sterile scissors and dropped directly into a sterile specimen container. illustrationcondom catheterA specially designed condom that includes a collection tube attached to the distal end. The tubing carries urine to a collecting bag. Its use prevents men with urinary incontinence from soiling clothes or bed linens. CAUTION!Continual use of this device may excoriate the skin of the penis. See: Catheter: External Condomdouble-channel catheterA catheter providing for inflow and outflow. elbowed catheterProstatic catheter.eustachian catheterA catheter passed into the eustachian tube through the nasal passages to ventilate the middle ear.female catheterA catheter about 5 in (12.7 cm) long, used to pass into a woman's bladder.Foley catheter See: Foley catheterglide catheterA catheter inserted into the ureter to remove impacted kidney stones. A lubricated wire is advanced past the obstructing stone. The glide catheter is mounted on the wire, moved toward the kidney beyond the stone, and used to snare and retrieve the stone. guide catheterA catheter that makes it easier to enter that vessel with other devices or instruments. Guide catheters are used to facilitate the placement of lasers, stents, and balloons for angioplasty. heparin-bonded catheterA pulmonary artery catheter with a heparin coating to reduce the risk of thrombus formation.Hickman catheter See: Hickman catheterimpregnated catheterA catheter coated with a medication to prevent complications of prolonged insertion in the body. Commonly used coatings include antibiotics and antiseptics. indwelling catheterAny catheter that is allowed to remain in place in a vein, artery, or body cavity.indwelling pleural catheterPleural catheter.intra-aortic catheter See: intra-aortic balloon counterpulsationintrauterine pressure catheter Abbreviation: IUPC
A catheter inserted into the uterus of a woman during labor, when labor is protracted, arrested, or when the force of uterine contractions are difficult to monitor indirectly. intravenous catheterA catheter inserted into a vein to administer fluids or medications or to measure pressure.Karman catheter See: Karman cathetermale catheterA catheter 12 to 13 in (30.5 to 33 cm) long, used to pass into a man's bladder.pacing catheterA catheter inserted most commonly into the right side of the heart via the brachial, femoral, internal jugular, or subclavian vein for temporary pacing of the heart. The pacing wires or leads provide the electrical stimulus from an external source (a pulse generator). peripherally inserted central venous catheter Abbreviation: PICC, PICC line
A soft, flexible central venous catheter, inserted in a vein in the arm and advanced until the tip is positioned in the axillary, subclavian, or brachiocephalic vein. It may also be advanced into the superior vena cava. A PICC is commonly used for prolonged antibiotic therapy, total parenteral nutrition, continuous opioid infusion, or intermittent chemotherapy. pharyngeal suction catheterA rigid catheter used to suction the pharynx during direct visualization. Synonym: Yankauer suction catheterpleural catheterA small chest catheter inserted between the parietal and visceral pleura and used to drain recurrent pleural effusions, e.g., in patients with cancer. Synonym: indwelling pleural catheterpresternal catheterA catheter used for peritoneal dialysis that exits the chest instead of the lower abdomen. It is made of two silicone rubber tubes joined at the implantation site by a titanium connector that links its abdominal and presternal parts. prostatic catheterA catheter, 15 to 16 in (38 to 40.6 cm) long, with a short elbowed tip designed to pass prostatic obstruction. Synonym: elbowed catheterpulmonary artery catheterA catheter inserted into the pulmonary artery to measure pulmonary artery pressures, pulmonary capillary wedge pressure, and, indirectly, left atrial pressure and cardiac output. self-retaining catheterA bladder catheter designed to remain in place (e.g., a Foley catheter).SUPRAPUBIC CATHETER: used to drain urinesuprapubic catheterA catheter that permits direct urinary drainage from the bladder through the lower abdominal wall from a surgically fashioned opening located just above the pubic symphysis. Suprapubic urinary diversion is typically but not exclusively used as a temporary means of decompressing the bladder when the urethra is obstructed, e.g., in children with congenital deformities of the penis or urethra, or in adults with bladder outlet obstruction. When it is used for this purpose, it is considered a bridge before definitive surgery. See: suprapubic aspiration of urine; illustrationPatient careThe nurse observes for hemorrhage or prolonged hematuria and signs of local or systemic infection. Aseptic technique is used during dressing or equipment changes. Bladder irrigation is performed as prescribed. Medications, e.g., analgesics, antispasmodics, and bowel stimulants, are administered as prescribed. The patient's ability to micturate is evaluated. Intake and output are monitored and recorded. Fluids are forced unless otherwise restricted to ensure passage of dilute urine. Swan-Ganz catheter See: Swan-Ganz catheterTenckhoff peritoneal catheter See: Tenckhoff peritoneal cathetertriple-lumen catheter Abbreviation: TLC
A central catheter containing three separate channels or passageways.tunneled central venous catheterAn intravenous catheter inserted into the subclavian or internal jugular vein and then advanced into the right atrium or superior vena cava. The proximal end is tunneled subcutaneously from the insertion site and brought out through the skin at an exit site below the nipple line. Commonly used tunneled catheters include the Hickman and Broviac catheters. umbilical vein catheterA catheter placed in the umbilical vein of an infant to facilitate administration of medicines parenterally or to do an exchange transfusion.vertebrated catheterA catheter in sections to be fitted together so that it is flexible.winged catheterA catheter with little flaps at each side of the beak to help retain it in the bladder.Word catheterA rubber catheter with an inflatable balloon at its end, used to treat cysts or abscesses, e.g., Bartholin gland cysts in the vulva.Yankauer suction catheter See: Yankauer suction catheter
triple-lumen catheter Abbreviation: TLC
A central catheter containing three separate channels or passageways.See also: catheter
chromatography (kro?ma-tog'ra-fe) [ chrom- + -graphy] The separation of two or more chemical compounds in a liquid or gaseous mixture by their removal at different rates based on differential solubility and adsorption. This separation is often accomplished by letting the chemicals percolate through a column of a powdered adsorbent or by passing them across the surface of an adsorbent paper, among other techniques.chromatographic (-mat?o-graf'ik), adjectiveadsorption chromatographyChromatography accomplished by applying the test material to one end of a sheet or column containing a solid. As the material moves, the various constituents adhere to the surface of the particles of the solid at different distances from the starting point according to their chemical characteristics. column chromatographyA form of adsorption chromatography in which the adsorptive material is packed into a column.gas chromatographyAn analytical technique in which a sample is separated into its component parts between a gaseous mobile phase and a chemically active stationary phase.gas-liquid chromatography Abbreviation: GLC
Chromatography in which a gas moves over a liquid, and chemical substances are separated on the liquid by their different adsorption rates.gel filtration chromatographyA type of column chromatography in which chemicals are separated via pores according to their molecular size. high-performance liquid chromatography Abbreviation: HPLC
Application of high pressure to liquid chromatography technique to increase separation speed and enhance resolution. Synonym: high pressure liquid chromatographyhigh pressure liquid chromatographyHigh-performance liquid chromatography.paper chromatographyChromatography in which paper strips are used as the porous solid medium.partition chromatographyChromatography in which substances in solution are separated by being exposed to two immiscible solvents. The immobile solvent is located between the spaces of an inert material such as starch, cellulose, or silica. The substances move with the mobile solvent as it passes down the column at a rate governed by their partition coefficient. thin-layer chromatography Abbreviation: TLC
Chromatography involving the differential adsorption of substances as they pass through a thin layer or sheet of cellulose or some other inert compound.
thin-layer chromatography Abbreviation: TLC
Chromatography involving the differential adsorption of substances as they pass through a thin layer or sheet of cellulose or some other inert compound.See also: chromatography
count (kownt) 1. The number of units in a sample or object.2. To enumerate. absolute granulocyte count Abbreviation: AGC
The total number of neutrophils, basophils, and eosinophils in a specimen of blood.absolute neutrophil count Abbreviation: ANC
The actual number of neutrophils in a cubic millimeter of blood. The approximate normal range is 3000 to 6000 cells/mm3. This figure is measured before and after drugs are given that may lower neutrophil counts, such as those used in cancer chemotherapy. Generally, chemotherapy is not given unless the patient's ANC is greater than 1000. Patients with an ANC of less than 500 cells/mm3 are at high risk for infection. See: neutrophilCAUTION!The development of fever in a patient with neutropenia secondary to chemotherapy is an indication for urgent medical evaluation and prompt institution of broad-spectrum antibiotics. absolute phagocyte count Abbreviation: APC
The number of phagocytes (neutrophils and monocytes-macrophages) in a cubic millimeter of blood. The APC is the sum of the neutrophils (segs and bands), monocytes, and macrophages times one hundredth (1/100) of the white blood cell count. See: absolute neutrophil count; blood countblood countThe number of red cells and leukocytes per microliter (µl) of whole blood. Normally, the number of erythrocytes in men averages 5 million/µl; in women, 4.5 million/µl. Prolonged exposure to high altitude increases the number. Leukocytes average 5000 to 10,000/µl. Platelets range from 140,000 to 400,000/µl. Hemoglobin (12 to 18 g/100 ml) and hematocrit (38% to 48%) are determined from samples of whole blood. complete blood count Abbreviation: CBC
A laboratory evaluation of all the cells that circulate in the blood, including the number and the hemoglobin content of red blood cells, the white blood cells (and their subtypes), and platelets. The typical CBC provides assessments of size and shape of red blood cells and platelets as well. Patient careThe CBC is among the most common blood tests performed in the clinical laboratory and aids in the diagnosis of anemia and erythrocytosis, bleeding and the repletion of blood cells by transfusion, thrombocytopenia and thrombocytosis, and infections and leukemias. Blood is obtained for the test from venipuncture or aspiration from an indwelling vascular access or port. It is taken to the laboratory in a tube that contains the anticoagulant ethylenediaminetetraacetic acid (EDTA). differential blood countThe number and type of white blood cells as determined by microscopic examination of a thin layer of blood on a glass slide stained to show the shape of the various cells. The number and variety of white cells in a sample of a given size are obtained. Even though the red cells are not counted by this method, their shape, size, and color can be evaluated. Some blood diseases and inflammatory conditions may be recognized in this way. In a differential count, the varieties of the leukocytes and their percentages normally should be: neutrophils (segmented), 40% to 60%; eosinophils, 1% to 3%; basophils, 0.5% to 1%; lymphocytes, 20% to 40%; monocytes, 4% to 8%. pollen countThe concentration of grains of pollen found in the atmosphere on a given day in a specific location. The measurement is used by allergy sufferers to forecast the likelihood they will have allergic symptoms, e.g., sneezing, sniffling, or wheezing. surgical countCounting the exact number of sponges, instruments, and other materials before, during, and after an operation in order to reduce the likelihood of leaving an object inside a body cavity. total lymphocyte count Abbreviation: TLC
The number of lymphocytes in a specimen of blood. The count may be increased in clonal diseases such as chronic lymphocytic leukemia or decreased in diseases such as AIDS. In AIDS, decreases in the total lymphocyte count usually reflect a marked decline in the number of helper T4 cells.
total lymphocyte count Abbreviation: TLC
The number of lymphocytes in a specimen of blood. The count may be increased in clonal diseases such as chronic lymphocytic leukemia or decreased in diseases such as AIDS. In AIDS, decreases in the total lymphocyte count usually reflect a marked decline in the number of helper T4 cells. See also: countTLC Abbreviation for total lung capacity. |