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GLOSSARY OF TEST TYPES
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A
AGGLUTINATION -- Clumping or gathering together of cells (usually
red blood cells) into a mass. Normally each cell exists
separately.
ANALYTICAL CHEMICAL ANALYSIS -- Separates, determines and analyzes
the quantity of any specific chemical or substance.
APPLANATION TONOMETRY -- Measures pressure in the interior portion
of the eye. After eye is anesthetized, tonometer (mounted on a
special lamp used by ophthalmologists) is pressed against the
cornea, and pressure is measured.
ASSAY -- Determination of the amount of a particular constituent of
a mixture or the biological or pharmacological potency of a drug.
ATOMIC ABSORPTION SPECTROSCOPY -- Measures trace elements, such as
calcium, magnesium or copper, in body fluids.
C
CT -- Computer tomography. See TOMOGRAPHY; CT SCAN.
CT SCAN -- Procedure in which an extremely narrow X-ray beam passes
through a cross-section of the body or brain. It is picked up by
an electronic instrument called a SCINTILLATOR rather than being
exposed on X-ray film. Scintillator reads the density that
tissue X-rays pass through. A computer prints out the densities
as an illustration of the cross-section.
CATHETERIZATION -- Passage of a tubular, flexible, surgical
instrument called a CATHETER into a cavity of the body. Used to
withdraw fluids.
CATION-EXCHANGE CHROMATOGRAPHY -- Chromatography technique that
exchanges one cation, such as sodium, for another cation, such as
potassium. See CHROMATOGRAPHY.
CENTRIFUGATION -- Process of separating lighter portions of a
solution, mixture or suspension from heavier portion by
centrifugal force. Usually accomplished in a centrifuge, which
spins at very high speed.
CHEMICAL ASSAY -- see ASSAY.
CHROMATOGRAPHY -- Group of techniques used to separate mixtures of
substances based on differences in the relative affinities of the
substances for two different media. One media is a moving fluid;
the other is stationary.
COLONOSCOPY -- Examination with an elongated, flexible scope that
allows view of entire colon.
COLOR-COMPARISON ANALYSIS -- Comparing color of test to color on a
predetermined chart.
COLORIMETRY (COLORIMETRICALLY) -- instrument (colorimeter) measures
color differences. Used in measuring the color of blood to
determine the proportion of hemoglobin.
COLORIMETRICALLY -- See COLORIMETRY.
COMPLEMENT FIXATION -- Consumption of complement upon reaction with
immune complexes containing complement-fixing antibodies. Widely
used to detect antigens or antibodies.
CONSUMPTIVE COAGULOPATHY -- Process of clot formation.
D
DIFFERENTIAL DOUBLE IMMUNOASSAY -- Measures antigen-antibody
interaction.
DIFFERENTIAL PRECIPITATION -- Observation of the thickness of the
layers; also the amount of time it takes for substances to settle
down in solid particles.
DISHE CARBAZOLE REACTION -- Amide groups of urea are replaced by
hydrazine residues.
DYE-COUPLE STARCH METHOD -- Starch is joined to a dye to determine
the chemical analysis of the substance being studied.
E
ELECTRODE ANALYSIS -- Any test that uses an electric conductor to
apply current for analyzation.
ELECTROLYTE ANALYZER -- Electronic hardware used to measure the
quantity of electrolyte in blood or urine.
ELECTROPHORESIS -- Technique of applying an electrical charge to
primary plasma proteins and observing their migration on paper.
ELECTROPHORETIC PATTERNS -- Patterns made by the movement of
charged particles suspended in a liquid under the influence of an
applied electric field.
EMISSION-FLAME SPECTROPHOTOMETRY -- Estimates the quantity of
coloring matter in a solution by the quantity of light absorbed
(as indicated by the spectrum) in passing through the solution.
ENDOSCOPY -- Visual examination of any cavity of the body with
special scope.
ENZYMATIC ANALYSIS -- Enzymes hasten the completion of technique
being used.
ENZYME IMMUNOASSAY -- Assays using catalyzing properties of enzymes
to detect immunologic reactions. See IMMUNOASSAY; ASSAY.
ENZYME-MULTIPLIED RADIO-IMMUNOASSAY -- Radio-immunoassay using
observations made after adding an enzyme to radioactive material
being measured. See RADIO-IMMUNOASSAY.
F
FERRIC-CHLORIDE REACTION -- Non-specific colorimetric test used to
detect a variety of substances in urine. See COLORIMETRY.
Addition of acidic solution of ferric chloride to specimen
results in formation of colored products with a number of
metabolites.
FLOCCULATION TECHNIQUE -- Formation of downy masses of precipitate
in a precipitin test or formation of agglutinated bacteria in an
agglutination test for the H antigens of salmonella species. See
AGGLUTINATION.
FLUORESCENCE -- Property of emitting light while exposed to light.
The wavelength of the emitted light is longer than that of the
absorbed light. Fluorescent substances that simultaneously
absorb and emit light appear luminous. Fluorescence in tissues
is induced by staining tissue with fluorescent dyes.
FLUORESCENT SPOT-SCREENING -- Uses property of some substances to
emit light while exposed to light.
FLUOROMETRIC ANALYSIS (FLUOROMETRY) -- Technique for identifying
minute amounts of a substance by detection and measurement of the
characteristic wavelength of the light it emits during
fluorescence. Used to measure urine hormones.
FLUOROSCOPIC IMAGES -- Continuous X-ray images seen through a
fluoroscope.
FRACTIONAL ANALYSIS -- Separating samples of any substance, such as
by heat or centrifugation, to allow analysis of various
components.
G
GAS CHROMATOGRAPHY -- Type of automated chromatography. Sample is
dissolved in a solution, vaporized and carried by inert gas
through a column to the detector. Sample components are
separated from each other by passage through the column which is
packed with an absorbent or adsorbent. Each component produces a
separate peak in the detector output which is graphed by a chart
recorder. See CHROMATOGRAPHY.
GEL DIFFUSION -- Diffusion of an antigen or antibody through a
semisolid medium, usually agar or agarose gel. Results in a
precipitin reaction.
GENETIC COMPLEMENT -- Two independent pairs of non-allelic genes
produce a specific effect. Neither will produce its effects in
the absence of the other.
GLOMERULAR-FILTRATION RATE (GFR) -- Rate at which a given compound
passes through the glomeruli in a given time (usually per
minute). If a compound is not reabsorbed or excreted, the amount
of compound found in the urine in the given time is a measure of
the GFR.
GLUCOSE OXIDASE/HEXOKINASE METHOD -- Technique for detecting
glucose in the urine by using a reagent strip that is
plastic-coated with glucose oxidase and glucose hexokinase. See
REAGENT STRIP.
H
HEAT ACTIVATION -- Part of chemical analysis technique that
observes activation of a chemical process at various levels of
heat.
HEAT-STABILITY TEST -- Laboratory study that helps identify
substances by subjecting them to various levels of heat and
observing their melting points.
HEMAGGLUTINATION-INHIBITION TEST -- Highly sensitive procedure for
measuring soluble antigens in specimens. Specimen is first
incubated with homologous antibody then incubated with
antigen-coated red cells. It is also a procedure for measuring
blood antibodies against a hemagglutination virus. The highest
dilution of blood that completely inhibits hemagglutination by a
standardized viral preparation is reported as the
HEMAGGLUTINATION TITER.
HEMATOCRIT -- Detects anemia and other blood disorders. It is
expressed as the percentage of red blood cells in whole blood.
HEMOLYTIC ASSAY -- Measures quantity or quality of destruction of
red blood cells.
I
IMMUNOASSAY -- Any of several methods for quantitative
determination of chemical substances that use binding between an
antigen and homologous antibodies. These include radio-immunoassay
and enzyme immunoassay. See RADIO-IMMUNOASSAY; ENZYME
IMMUNOASSAY.
IMMUNOELECTROPHORESIS -- Technique combining protein
electrophoresis and double immunodiffusion. See ELECTROPHORESIS.
Proteins are separated by agarose-gel electrophoresis, then
specific anti-sera are placed in a trough cut parallel to the
protein track. Proteins and antibodies are allowed to diffuse
through the gel. Proteins branch out in all directions from a
common center. Antibodies diffuse perpendicularly from the
trough, resulting in a distinct elliptical precipitin arc.
IMMUNOFLUORESCENCE -- Any chemical method that uses an antibody
labeled with a fluorescent dye. Test is called DIRECT if a
specific antibody or anti-serum is conjugated with a fluorochrome
and used as a specific fluorescent stain. Test is called
INDIRECT if the fluorochrome is attached to an anti-globulin and
a tissue constituent is stained using an unlabeled specific
antibody and the labeled anti-globulin, which binds the unlabeled
antibody.
ION-EXCHANGE CHROMATOGRAPHY -- Chromatography using an ion-exchange
resin as the stationary phase. See CHROMATOGRAPHY. The
stationary phase is an ion-exchange, and the mobile phase is a
buffer solution.
ISOENZYME FRACTIONATION -- Sophisticated laboratory technique that
splits enzymes to provide great specificity and sensitivity in a
test not obtainable with study of the full enzyme. See FRACTIONAL ANALYSIS.
ISOPROPANOL-SOLUBILITY TEST. Measures how well a substance
dissolves in isopropanol.
K
KINETIC COLORIMETRIC TECHNIQUE -- Measures color differences as
color moves across the instrument. See COLORIMETRY.
KINETIC MEASUREMENT -- Study of the turnover of some factor, such
as red blood cells (erythrokinetics), leukocytes (leukokinetics),
iron (ferrokinetics). The rate of production, clearance or
destruction and duration of life span are usually determined.
L
LATEX-AGGLUTINATION TEST (LATEX FIXATION TEST) -- Type of
agglutination test using latex particles as passive carriers
of adsorbed antigens. See AGGLUTINATION. Particles clump
together following the addition of a specific antibody.
LATEX-FIXATION TEST -- See LATEX AGGLUTINATION TEST.
LOW-SUBSTRATE ASSAY -- Measures effectiveness of an enzyme acting
on another substance. See ASSAY.
M
MICRODIFFUSION -- Method of separating volatile substances from a
biological specimen.
MOUSE BIOASSAY -- Study of mice cells after injecting them with
material to be measured.
MYELOGRAM -- Injecting dye into the spinal canal to study bones of
the spinal column.
N
NEPHELOMETRY -- Test to determine the concentration of solids
suspended in a liquid or gas. May be used to determine the
number of bacteria in a specimen.
P
PEROXIDASE STAINING -- Chemical procedure for demonstrating
peroxidases in frozen or freeze-dried tissue sections or
alcohol-fixed smears (for leukocytes).
PHASE MICROSCOPY -- Microscope that alters the phase relationships
of the light passing through it and light passing around the
object. Contrast permits examination of the object without
staining or other special preparation.
PHOTOCOLORIMETRY -- Laboratory technique that uses a colorimeter to
measure color differences and photography to make a permanent
record. See COLORIMETRY.
PHOTOMETRY -- Measurement of the intensity of light.
PROVOCATIVE TESTING -- Method in which a substance suspected of
causing symptoms is purposely given, under safe, controlled
circumstances.
Q
QUALITATIVE TEST -- Determines the presence or absence of a
particular property or condition. Determines ingredients of a
substance.
QUANTITATIVE TEST -- Accurate determination of the quantity of a
chemical element, compound or functional group present in a
specimen.
R
RADIAL IMMUNODIFFUSION (SINGLE RADIAL DIFFUSION) -- Method for
determining the concentration of antigen or antibody.
RADIO-IMMUNOASSAY -- Highly sensitive, specific assay method that
uses the competition between radio-labeled and unlabeled
substances in an antigen-antibody reaction to determine
concentration of the unlabeled substance. Can be used to
determine antibody concentrations or to determine the
concentration of any substance against which specific antibodies
can be produced. See ASSAY; IMMUNOASSAY.
RADIO-ISOTOPE ASSAY -- Radiation from radio-isotope can be detected
with special instruments. Determining where radioisotopes go in
the body allows diagnosis of diseases that cannot be detected
otherwise. See ASSAY.
RADIO-ISOTOPE SCAN -- Radioactive material helps outline size,
shape and exact location of an organ, chamber or duct after
isotope is injected into body.
REAGENT STRIP -- Paper strip with one or more areas impregnated
with chemicals that undergo a color change when they react with
specific substances. Substance concentrations in specimen
(usually urine or blood) are indicated by changes in color, which
are compared with a color chart prepared by the manufacturer.
REVERSE-PASSIVE AGGLUTINATION -- Various chemicals reverse the
process of blood clotting.
ROENTGENOGRAM -- A film produced by exposure to X-rays.
S
SERIAL MEASUREMENTS -- Series of titers measure body's response to
an antigen. A rising titer may give important objective evidence
toward establishing a precise diagnosis. For example, a serial
determination that shows titers of cold agglutinens of 1:28;
1:64; 1:128 suggests viral pneumonia. See TITER.
SHEEP-CELL AGGLUTINATION -- Any agglutination test using red blood
cells from sheep, such as the Rose-Waaler test. See
AGGLUTINATION.
SPECIFIC GRAVITY -- Weight of a substance is compared to the weight
of an equal volume of another substance taken as standard.
SPECTROFLUOROMETRY -- Analytic method for determining fluorescent
compounds.
SPECTROPHOTO FLUOROMETRY -- Combining techniques of
spectrophotometry and fluorescence analysis.
SPECTROPHOTOMETER -- Estimates the quantity of coloring matter in a
solution by the quantity of light absorbed (as indicated by the
spectrum) in passing through the solution.
T
TOMOGRAM -- Roentgenogram of a selected layer of the body made by
tomography.
TOMOGRAPHY (BODY SECTION X-RAYS) -- A special technique to show in
detail images of structures lying in a plane of tissue.
TURBIDIMETRIC TECHNIQUE -- Measures cloudiness (turbidity) of a
solution by measuring the loss of intensity of a beam of light in
passing through the solution.
TURBIDEMETRICALLY -- Measurement of cloudiness (turbidity);
generally performed using a spectrophotometer or colorimeter that
measures the ratio of the intensity of light transmitted through
a dispersion to the intensity of the incident light. See
SPECTROPHOTOMETER; COLORIMETRY.
U
ULTRACENTRIFUGATION -- Subjection to the action of the
ultracentrifuge, which is a machine with an exceedingly high rate
of rotation that separates and sediments molecules of a
substance.
ULTRASONOGRAPHY (ULTRASOUND; SONOGRAM) -- View of deep structures
of the body by recording reflections or echoes of pulses of
ultrasound waves directed into tissues. Sound waves are
transmissible in liquid and solid.
ULTRAVIOLET MICROSCOPY -- Microscope that uses reflecting optics or
quartz and other ultraviolet-transmitting lenses with radiation
of less that 400mu wavelength as the image-forming energy.
W
WATER-CALORIC TESTS -- Tests status or function of the inner-ear
mechanism that allows you to maintain balance. Examiner
introduces water into the ear canal so it hits the ear drum
(tympanic membrane) for 30 seconds. Test uses water at 86F
(30.2C) and 111.2F (44.3C). Response is recorded on an
electronystagmograph. Occasionally ice water is used to complete
the study.
X
X-RAY -- High-energy, visible waves capable of penetrating the body
and creating shadows on photographic film. Shadows provide
images of body tissue through which X-rays pass. |
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From Complete Guide to Symptoms, Illness & Surgery by H. Winter Griffith, M.D. Copyright by Putnam Publishing Group. Electronic rights by Medical Data Exchange.
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