CC QC Flashcards
midpoint of a set of values
median
average of set of values. measures of central tendency
mean
the most frequent among all values/data
mode
laboratories are given samples with unknown conc. for them to test and results are compared with other laboratories
interlab QC
used for daily monitoring of accuracy and precision of method used. detects random and systematic errors.
intralab QC
defined as the ability of a method to measure the analyte of interest only
specificity
defined as the ability of a method to measure the analyte even at its lowest conc.
sensitivity
a colorless solution with a known conc. of substances used for calibration
standard
simplest expression of spread of distribution, it is the difference between the highest and lowest score in a data
range
most frequent used measure of variation
SD
index of precision
CV
used to assess if there is a statistical difference between the means of 2 groups of data
T-test
used to assess if there is a statistical difference between the SD of 2 groups of data
F-test
most widely used QC chart
plotted to give visual indication if lab test is working
shewhart levey-jennings chart ( dot plot)
six or more consecutive values that either increase or decrease gradually (will cross the mean) main cause: reagent deterioration
trend
six or more consecutive values that are distributed on one or the other side of the mean (does not cross the mean) main cause: improper instrument calibration
shift
used to check if there are significant differences between present set of values to that of past values on the sample of the same individual
delta check
a way of improving product processing to eliminate defects
six sigma
unit expression of wavelength
nanometer
distance between two successive peaks
wavelength
entity that this transmitted by electromagnetic waves
energy
number of waves that passes a point of observation per one unit of time
frequency
measure electric potential
potentiometry
measures light blocked
turbidimetry
measures light scattered molecules, used for measuring amount of Ag-Ab complexes
nephelometry
serves as both light source and cuvette
flame
separation is based upon differences in characteristics (both physical and chemical) of substances, used for amino acid determination, drugs and sugars
chromatography
square of SD
variance
nearness of measured value to that of the target value
accuracy
nearness of measured value to each other
precision
affects precision of repeated measures, by chance, varies from sample to sample
random errors
affects accuracy of mean measures, influence observation consistently in one direction
systematic error
error that occurs in hand written labels, request forms, and results, HIGHEST SOURCE OF ERROR IN THE LABORATORY
clerical error
type of systemic error in the sample direction and magnitude; the magnitude of change is constant and not dependent on amount of analyte
constant error
error dependent on analyte conc.
proportional error
errors encountered in the collection, preparation, measurement of samples including the transcription and releasing of lab results
variation
known analyte with multiple samples resembling human spx, serum-like yellow
control reagent
levels of control solutions in general cheistry
2
levels of control solutions in immunoassay
3
highly sensitive methods are prone to
false positive results
highly specific methods are prone to
false negative
what are the test for imprecision
SD, PRECISION, F-TEST
what are the test for inaccuracy
mean, accuracy, T-test
signifies constant systemic error
y-intercept
acceptable range of CV (beyond it determines an imprecise QC
2-4%
horizontal, abscissa, Ind Var
x-axis
vertical, ordinate, dependent var
y-axis
analyze precision within or between run or total imprecision
ANOVA (analysis of variance)
is the proposal that there is no difference in a comparison
null hypothesis (HO)
is incorrectly rejecting the null hypothesis and stating that two groups are statistically different when they really not
type I error (alpha error)
is incorrectly failing to reject the null hypothesis and stating that two groups are not statistically different when they really are
type II error (beta error)
states the relationship between pre-tests and post-tests
Bayes’ Theorem
best utilized to establish reference values
gaussian curve
(normal bell-shaped curve)
sequential analysis to detect change. its advantage is it can detect earliest errors of trend but only available in computers
cumulative sum graph (cumsum)
most common method used in cumsum
V-mask
analyze 2 samples, compare results obtained on a high and low control serum from different laboratories
youden plot (twin plot)
determine the specific performance limits of an assay, detects random and systematic errors through multiple rules
westgard control chart (multirule chart)
random errors in westgard control chart
1 2s,
1 3s,
R 4s
systematic errors in westgard control chart
2 2s,
3 1s,
4 1s,
6 x,
7 T,
8 15,
10x
type of control chart used to monitor either variables, or attributes type data using the monitored business or industrial process’s entire history output
EWMA chart
(exponentially weighted moving average chart)
control values that are too far from the mean or highly deviating values
outliers
at least how many individuals need to be tested, to derive reliable estimates of reference intervals?
120
measurement of organizations products or services against specific standards for comparison and improvement
benchmarking
trends on organizations productivity overtime
internal benchmarking
compares a laboratory’s productivity w/ that of other labs
external benchmarking
clinical laboratory category for secondary lab
routine chemistry
clinical laboratory category for tertiary lab
special chemistry
results difference of greater than __ indicates disagreement with other lab included
2SD
best chart for internal QC
LJ chart
best chart for external QC
youden chart
linear regression analysis used to compare two methodologies using the best fit line through the data points
deming regression analysis
graphical representation of the deming regression analysis
deming plot
lowest amount of analyte accurately detected by a method
LoD (limit of detection)
range of analyte conc. that can be directly measured without dilution, conc., or other pre-treatment
AMR (analytic measurement range)
refers to the difference between the measured value and the mean expressed as a number of SDs.
SDI (standard deviation index)
body component (e.g., fluid, urine, etc.) in which the analyte is to be measured
matrix
effects of a compounds on the accuracy of detection of a particular analyte
interference
ability of an analytic test to measure a known amount of analyte; a known amount of analyte is added to real sample matrices
recovery
random error plus systemic error
total error
- tool to reduce waste
- increase production and manufacture
-focuses on workflow speed
lean system
5s of lean system
sort
set in order
shine
standardize
sustain
+ (PDCA)
improvement methodology
- each phase has one or 2 key objectives and corresponding tasks to be completed
DMAIC (define, measure, analyze, improve, and control)
project coaches leaders
black belts
project team members
green belts
project sponsors
blue belts
most lab work are at what sigma levels?
3
recommended sigma levels
4
ideal sigma level
6
measures transmitted light in a colored solution
spectrophotometry
simplest type of absorption spectrometer, 1 measurement at a time
single beam spectrophotometer
splits monochromatic light into 2 components
double beam spectrophotometer
double beam in space uses how many photodetector/s?
2
double beam in time uses how many photodetector/s?
1
measurement of light intensity using specific wavelength
photometric measurement
measurement of light intensity in a narrower wavelength
spectrophotometric measurement
provide polychromatic light
light source
emits radiation that changes in intensity, widely used among lab
continuum source
emit a limited number of discrete lines or bands of radiation
line source
commonly used filters in fluorometers
mercury vapor lamps
(N: gas discharge lamp)
most commonly used for visible -infrared based sources
tungsten
routinely used for UV light based light source
deuterium
used in most spectrofluorometers utilizing high pressure for determining excitation spectra
xenon
(N: gas discharge lamp)
WHAT ARE THE UV LAMPS?
mercury
xenon
hydrogen
deuterium
WHAT ARE THE IR LAMPS?
merst glower
globar silicon carbide
minimizes unwanted stray light
entrance slit
isolate specific individual wavelength and sharp out off filter
monochromator
wedge shaped glass, quartz, sodium chloride
prisms
allows only a narrow fraction of the spectrum to reach the sample cuvette
exit slit
a.k.a absorption cell or analytical cell that holds the solution which conc. is to be measured
sample cuvette
most commonly used in sample cuvettes
alumina silica glass
conc. of the unknown substance is directly proportional to absorbed light/ inversely proportional to transmitted light
beer’s law
blank that contains only the serum but w/o the reagent
blanking technique
corrects the absorbance by the color of the reagents
reagent blank
measures the absorbance of the sample
sample blank
what will you do to cuvettes w/ scratch on optical surface
discard
range where silica cuvettes transmit light effectively
≥ 220
caused by prolonged standing w/ alkaline solutions
dissolving and etching
routine path length of cuvettes, to increase absorbance factor by 10x, increase length to 10 cm
1 cm
detects and converts transmitted light into photoelectric energy
photodetector
anode and cathode on glass tube
phototube
simplest and lest expensive photodetector (barrier layer cell)
photocell
most common, most sensitive photodetector
photomultiplier tube
Needs excitation
- measures light emitted by 1 atom burned in a flame
- excitation of electron from lower to higher energy state
flame emission photometry
has excellent linearity
photodiode
no excitation, needs pre-warming
- the most sensitive and specific among the 3 colorimetric method
atomic absorption spectrophotometry
a.k.a titration
unknown solution + known solution= color change
volumetry
chloride analysis
schales and schales
calcium analysis
EDTA titration method
amount of light blocked
turbidimetry
scattering of a beam o light b particles roughly the same size as the wavelength of light
tyndall scattering
emission of low-energy light quickly after absorbing high energy light
fluorescence
production of light
luminescence
predominantly elastic scattering of light by particles much smaller than the wavelength of the radiation
Rayleigh-debye scttering
elastic scattered light of particles that have a diameter similar to or larger than the wavelength of the incident light
Mie scattering
utilizes 2 monochromators
-amount of light emitted by a molecule after excitation by electromagnetic radiation
- AFFECTED BY QUENCHING
- measure amount of light over a DARK background
fluorometry
is the reduction or limitation of a particle in a excited state
quenching
no excitation is required and no monochromators are needed
chemiluminescence
changes in colligative property of solutions that occur due to variations in particle conc.
osmometry
osmotic particles
glucose, BUN, sodium
what are the colligative properties
osmotic pressure
boiling point
freezing point
vapor pressure
increase osmolarity.
increased: ?
decreased: ?
increased: freezing point
decreased: vapor pressure
use to scan and quantitate serum protein electrophoresis
densitometry
OD 450: ?
bilirubin
gold standard for new born screening
MS/MS
gold standard for drug testing
GC-MS
diffusion of molecules in 2D-plane system
planar form chromatography
diffusion of analytes in 3D-multidirectional system
column form chromatography
fragmentation and ionization of molecules using suitable source of energy
- DESTRUCTIVE
mass spectroscopy
fractionation of sugar and AA through whattman paper sorbent
thin layer chromatography
determine the structure of organic compound
-NON-DESTRUCTIVE
- requires larger sample volume
nuclear magnetic resonance spectroscopy
migration based on electrical charge
electrophoresis
migration based on PH gradient
isoelectric focusing
ISE that require no sample dilution
Direct Ise
ISE that require sample dilution
indirect ise
measurement amount of electricity at fixed potential in coulombs
- uses faraday’s law
coulometry
causes interferences in coulometry
bromide
cyanide
cysteine
