midterms Flashcards
It is a statement of variability and measures the significant differences between groups of data
Variance (V)
Separates white light
into various color
component.
DIFFRACTION
GRATINGS
For accuracy, a solution of known characteristics and of known value or whose concentration is accurately known
STANDARD SOLUTION
It is a system of techniques to ensure with a specified
degree of confidence that the result obtained from each
series of analysis is true and correct
QUALITY CONTROL
meaning of A in the absorbance formula
molar absorptivity
LABORATORY WORKFLOW
PRE ANALYTICAL PHASE
ANALYTICAL PHASE
POST ANALYTICAL PHASE
these are made by placing semi-transparent silver
films on both sides of a dielectric such as magnesium
fluoride
filters
The degree by which a method is easily repeated with less effort
Practicality
formula of transmittance
%T = I t/ I o x 100
It is the measure of central tendency
Arithmetic Value or Mean or average (x̄)
pogi ba si joshua
yes sobra opo
TYPES OF CUVETTE/ ANALYTICAL CELL
Borosilicate glass cuvette
Quartz or plastic
Alumina silica glass
Negative test result and do not have disease
TRUE NEGATIVE
a filter that transmits only frequencies within a selected band
BAND PASS
It is the migration of charged particles in an electric field
ELECTROPHORESIS
Formula for Diagnostic specificity
True negative/ true nega. + false pos x 100
It is composed of one known constituent only and used
as a basis of reference for the calculation of the value of the unknown
STANDARD SOLUTION
is the transmitted via electromagnetic waves that
are characterized by their frequency and wavelength
Energy
Proficiency testing- NEQAS
External Quality Control program
The ability of a method to measure only the component desired without the interference of some other substances present in the same sample
Specificity
It is used to compare results obtained on a high and low control serum from different laboratories
Youden Plot (with x and y axis)
A type of error that influences observations consistently
in one direction (constant difference)
SYSTEMATIC ERROR
The ability of a method to determine the exact value of the substance of interest in the sample
Accuracy
ability of method to have the same results
Reproducibility
It is the measure of spread of data; helps to describe the normal curve
Standard Deviation (SD)
It is a measure of the distribution range of values around the mean value or average
Standard Deviation (SD)
Emits radiation that changes in intensity, it is widely used in the laboratory
CONTINUUM SOURCE
Types of monochromator
prisms and diffraction grattings
An electron tube amplifying a current that can convert transmitted energy into an equivalent amount of electrical or photoelectric energy
PHOTODETECTOR
Negative test result but have the disease
FALSE NEGATIVE
states that the concentration of a unknown substance is directly proportional to the amount of light absorbed and inversely proportional to the logarithm of the transmitted light.
Beer’s Law
Serve as a reference for unknown
STANDARD SOLUTION
is the number of vibrations of wave per second.
Hertz
It is the percentile expression of the mean; an index of precision
Coefficient of Variation (CV)
meaning of I t in transmittance formula
transmitted light thru the sample
Liquid or lyophilized and Stable for a long period of time
CONTROL SOLUTION
is formed by controlled values that is either increase or decrease for at least 6 consecutive days
Trend
able to measure minute
concentration of the analyte
Analytical sensitivity
TYPES OF PHOTODETECTOR
Photocell/Photovoltaic cell/ Barrier layer cell
Photoemissive tube/Phototube
Photomultiplier tube
Formula of diagnostic sensitivity
true positive/ true pos. + false neg x 100
It can be rotated, allowing only the desired wavelength to pass through an exit slit.
PRISMS
the test must always give a
negative result in the absence of disease
Diagnostic specificity
It occurs when data elements are centered around the mean with the most elements close to the mean.
Gaussian Curve
Formed by controlled values that distribute themselves on one side of the mean for at least 6 consecutive days
Shift
Components of Electrophoresis
Electrical power, support medium, buffer, sample and detecting system
meaning of B in the absorbance formula
length of light through the solution
Factors affecting migration
Net electric charge of the molecule
Size and shape of molecule
Electric field strength
Nature of supporting medium
Temperature of operation
The ability of a method to detect and measure even the
smallest amount of the particular substance tested for
Sensitivity
It is also the degree by which significant deviations can be
detected
Sensitivity
Positive test result that also have disease
TRUE POSITIVE
It is a system of ensuring precision and accuracy in the
laboratory by using quality control reagents in every
series of measurements.
QUALITY CONTROL
when the values of the control fall outside the confidence limit
Out of control
T or F? During electrophoresis, proteins are negatively charged (anions) and they move towards the anode
True
A basis for varying differences between repeated measurement
variation in technique
It involves measurement of light transmitted by a solution in a much narrower wavelength to determine the concentration of light absorbing substances in the solution
SPECTROPHOTOMETRY
when the values of the control fall within the confidence limit
In control
Involves analyses of control samples together with the patient sample
Internal Quality Control program
For precision, a solution (either commercially or non-commercially prepared) composed of several known constituents which can be run simultaneously with the test to check the accuracy of the results. (w/ Normal and Pathologic ranges)
CONTROL SOLUTION
the test must always give a (+)
result in the presence of the disease
Diagnostic sensitivity
It controls the the width of light
beam
EXIT SLIT
meaning of I o in transmittance formula
transmitted light striking the sample.
discharge lamp produces a continuous source of radiation which covers both the UV and visible range.
Xenon
Positive test result but do not have disease
FALSE POSITIVE
Electrophoresis separates proteins on the basis of their electric charge and density
Serum Protein Electrophoresis (SPE)
is the total range of
wavelengths transmitted
BAND PASS
T or F? In the standard performance of serum protein electrophoresis (SPE), serum specimens are applied close to the cathode end of a support medium that is saturated with an alkaline buffer (pH 8.6)
True
Errors in Quality Control
VARIATIONS
Isolate specific wavelength of
light
monochromator
lamp routinely used to provide UV radiation
Deuterium
It sets the spectrophotometer reading to zero
BLANK SOLUTION
It is the closeness or the nearness of a test value (value
obtained) to the original value (predetermined value)
Accuracy
light bulb commonly used light source in the visible and near infrared region
tungsten
It demonstrate acceptable limits of variation in the results of an analytical method.
Shewhart-Levey Jennings Chart
The highest frequency of this type of error occurs with
the use of handwritten labels and request forms
CLERICAL ERROR
Purposes of Quality Control
To check the stability of the machine
To check the quality of reagents
To check for technical or clerical error if any was committed by the operator
The ability of a method to give repeated results on the same sample that agrees with one another
Precision
It is used to hold the solution in the instrument whose concentration is to be measured. It is made of glass, quartz or plastic.
CUVETTE/ ANALYTICAL CELL
These are control values that are far from the main set of
values
OUTLIERS
are simple, least expensive, not precise but useful
filters
minimizes unwanted or stray light and prevents the entrance of scattered light into the monochromator system
entrance slit
meaning of C in the absorbance formula
concentration of absorbing molecules/solution
A type of error which varies from sample to sample
RANDOM ERROR
able to measure only one
unknown substance
Analytical specificity
Plotted with the accumulated differences between QC results and the target means
Cumulative Sum Graph
A solution without the specimen
BLANK SOLUTION
absorbance formula
A= abc = 2-log%T
It produce monochromatic light based on the principle of constructive interference of waves – light waves enter one side of the filter and are reflected at the second surface
filters
It has small grooves cut
at such as angle that each groove behave like a very small prism.
DIFFRACTION
GRATINGS
It provides polychromatic light and must generate sufficient radiant energy or power to measure the analyte of interest
light source
COMPONENTS OF SPECTROPHOTOMETER
Light source
Entrance slit
Monochromator
Exit slit
Cuvet
Photodetector
Meter or Read out device
The fundamental basis of any statistical analysis
Machine problems
Contaminated reagent
Technical errors
emits limited radiation and wavelength
line source
WHEN TO PERFORM QUALITY CONTROL
Beginning of each shift (Daily testing)
New instrument
After an instrument is serviced
When reagent lots are changed
After calibration
Whenever patient results seem inappropriate
Wedge-shaped pieces of
glass or quartz, NaCl, or
some other material that
allows transmission of
light.
PRISMS
is the distance between two successive peaks and it is expressed in terms of nanometer
Wavelength
