INSTRUMENTATION Flashcards
Uunit for volume
liter / L
unit used for catalytic activity
Katal / Kat
unit used for mass
Kilogram / kg
unit for amount of substance
mole / mol
unit used for length
meter / m
unit used for luminous intensity
Candela/cd
unit for electric current
Ampere / A
unit for thermodynamic temperature
Kelvin / K
temperature conversion : farenheit to celsius
C = ( F - 32 ) / 1.8
temperature conversion : celsius to farenheit
F = 1.8 x C + 32
factor for pico
10^(-12)
factor for nano
10^(-9)
factor for micro
10^(-6)
factor for milli
10^(-3)
factor for centi
10^(-2)
factor for deci
10^(-1)
number of moles of solute per LITER OF SOLUTION
MOLARITY
molarity formula
M = g/L / MW or g/dl x 10 / MW
M = N / V
normality formula
N = g/L / EW or g/dl x 10 / EW
N = M x V
equivalent weight formula
MW / valence
number of moles of solute per KILOGRAM OF SOLVENT
molality
amount of solute per 100 total unit if solution. ; expressed as % w/v, w/w, or v/v
percent solution
expression of relative concentration
dilution
volume of sample or stock divided by total volume of solution
simple dilution
done when a weaker reagent concentration is needed than the stock substance available
dilution of stock solution
done when the analyte concentration is too high and exceeds the detection limit of the method
dilution of sample
smount of something relative to another; expressed as part per part or part per whole
ratio
measures of center (3)
mean, median, mode
average or arithmetic mean
mean
midpoint of a data set after the values have been rank-ordered
median
most frequently occuring value in a data set
mode
also known as variability or distribution
measures of spread
measures of spread (3)
standard deviation
coefficient of variation
range
data points are distributed symmetrically around the mean (bell shaped curve) with most values close to the center
gaussian/normal distribution
the empirical rule that Gaussian distribution follows
68-95-99.7% rule - confidence interval
a pair of medical decsion points that span the limits of results expected for a defined HEALTHY POPULATION
reference interval
in verifying a reference interval, it requires at least ___ study individuals ; Reference interval is adopted if ____ of the subjects fall outside the range
20 ; 10% or less
in establishing a reference interval, it requires at least ____ study individuals ; RI is set based on the ___
120 ; 95% CI = mean +/- 25
first step in method evaluation; usually done by running two control materials twice a day over a 10-day period
precision study
precision study is the first step in method evaluation; usually done by running two control materials ___ a day over a ____ period
twice ; 10-day
involves spiking a sample with a known amount of an analyte and determining HOW MUCH IT CAN BE DETECTED by the method in the presence of other compunds in the matrix
recovery study
compares the MEANS of the two groups of data or the ACCURACY of two method
T test
compares the STANDARD DEVIATIONS of two groups of data or the PRECISION of two procedures
F test
used to compare two methods using the best fit LINE through the DATA POINTS
linear regression
VOYD
vertical
ordinate
y axis
dependent
HAXI
Horizontal
Abscissa
X axis
Independent
if there is no cv cut off value for a given analyte, the rule of thumb applies in which the cv must be ____ to be precise
less than 10%.
best indicator of precision
coefficient of variation
the relationship between cv and precision
inversely proportional
a measure of spread that is greatly affected by outliers making it unreliable
range
commonly used as the confidence interval in research and laboratory statistics
95%
ability of a method to detect the smallest concentration of an analyte
analytical sensitivity
ability of method to detect ONLY the analyte of interest
analytical specificity
ability of test to detect A GIVEN DISEASE or condition ; proportion of individuals WITH THE DISEASE who have a positive result
diagnostic sensitivity
ability pf a trst to detect the ABSENCE of a given disease or condition ; proportion of individuals with NO DISEASE who have a NEGATIVE test result
diagnostic specificity
probability that a POSITIVE test result indicates disease ; proportion of individuals with a POSITIVE RESULT who TRULY HAVE THE DISEASE
postive predictive value
probability that a NEGATIVE test result indicates absence of disease ; proportion of individuals with a NEGATIVE RESULT who TRULY DO NOT HAVE THE DISEASE
negative predictive value
most widely used approach to quality improvement in the healthcare
PDCA CYCLE / DEMING CYCLE
provides both a management philosophy organizational development process for improvement of quality on ALL ASPECTS of work
Total Quality Management (TQM)
TQMs Five-Q Framework
quality planning
quality laboratory process
quality control
quality assessment
quality improvement
based on the statistics and quantitative measurements applied in the clinical laboratory to REDUCE the frequency of test ERRORS or the number of DPMOs
Six sigma
5 steps of SIX SIGMA (DMAIC)
define
measure
analyze
improve
control
designed to REDUCE WASTE ; increase efficiency and improve customer satisfaction; often used in clinical laboratories to improve TURN AROUND TIME
lean
categories of waste ( DOWN TIME )
defects
overproduction
waiting
non utilized talents
transport
inventory
motion
excess processing
lean-six sigma colored belt: understands the BASICS of lean-six sigma
yellow belt
lean-six sigma colored belt: team members who contribute APPROXIMATELY 20% of their time to quality imorovement projects
green belt
lean-six sigma colored belt: TEAM LEADERS who dedicate as much as 100% of their time to quality improvement projects
black belt
lean-six sigma colored belt: BLACK BELT with at least 2 YEARS of experience ; lean-six sigma advisers/coaches
master
process by which the laboratory ensures quality results by closely monitoring preanalytical, analytical, and postanalytical phases of testing
quality assessment / quality assurance
ability to maintain accuracy and precision over an extended period of time during which equipment, reagents and personnel may change
reliability
closeness of the result to the true or actual value
accuracy
ability to produce a series of RESULTS that AGREE CLOSELY with each other ; commonly expressed in terms of coefficient of variation
precision
aka repeatability or reproducibility
precision
involves the analysis of at least 2 levels ofcontrol every 24 hours
internal quality control
involves the analysis of at least ___ levels of control every ____
2 levels ; 24 hours
in internal quality control, initial control limits are establisshed by analyzing controls for at least ___ consecutive days or runs
20
important for daily monitoring of accuracy and precision of analytical method
internal quality control
involves testing BLIND samples ( unknown concentration of analytes) sent periodically by regulatory agencies to participating laboratories
external quality assessment
aka the unknown concentration of analytes tested in external quality control
blind samples
important for maintaining the long term accuracy of analytical methods
external quality assessment
it is the distance from the mean in terms of standard deviation
z score
type of error taht is due to chance or an unpredictable cause; does not recur in regular pattern
random error
a type of error that is usually a one-time error
random error
random error: violations of westgard rules
12s, 13s, R4s
a type of error in which the causes are as follow : instrument instability e.g. temperature and voltage fluctuations, dirty glassware, sampling error, improper mixing of sample and reagent, operator variability e.g. pipetting error, anticoagulant or drug interference
random error
a type of error in which Causes are as follow: deterioration of reagents, change in reagent lot, unstable reagent blanks, calibration error, changes in standard concentration, contaminated control solutions, diminishing lamp power, dirty photometer, faulty ISE, and pipettor maintenance error
systematic error
a type of error thst affects precision
random error
a type of error that affects accuracy
systematic error
it is indicated by shift, trend or violation of the 22s, 44s, 81s, 10x
systematic error
westgard rule violations of systematic error
22s, 44s, 81s, 10x
type of error that affects ALL RESULTS, may be CONSTANT or PROPORTIONAL
systematic error
RECURRING ERROR inherent in test procedure; influences observations in ONE DIRECTION
sysematic error
abrupt change in the distribution of control values such that they accumulate on one side of the mean for 6 consecutive days
shift
major cause of shift
calibration or error in standard preparation
GRADUAL change in the distribution of control values such that they continue to INCREASE or DECREASE over a period 6 consecutive days passing through the mean
trend
major cause of trend
deterioration of reagent
HIGHLY DEVIATING control values caused by both random or systematic errors
outliers
prepared by plotting the CUSUM points or the algebraic sum of the difference between each QC result and the mean on the y axis and the run number the x axis.
CUSUM chart
used for interlaboratory comparison of monthly means by plotting the mean value FOR ONE SAMPLE on the y axis and the mean value FOR ANOTHER on the x axis;
tonks-youden / twin plot
effective method for comparing both within-laboratory and between-laboratory variability y
tonks-youden / twin plot
most commonly used QC chart
Shewart Levey - Jennings chart
hierarchy of controls from most to least effective
ELIMINATION
SUBSTITUTION
ENGINEERING CONTROLS
ADMINISTRATIVE CONTROLS
PPE
isolate the people from the hazard
engineering controls
change the way people work
administrative controls
fume hoods, bsc, splash guards, guards on moving parts are example of what type of control
engineering controls
warning signs, SOPs, emergency response procedures are what type of control
administrative controls
sequence of donning
gown, mask, goggles, gloves
sequence of doffing
gloves, goggles, gown, mask
bsc type that sterilizes only the air to be exhausted and does not protect the work surface
bsc class I
bsc type that is commonly used un microbiology
bsc class II
bsc class II is also called as
vertical laminar flow bsc
bsc type that sterilizes the air that flow over the infectious material as well as the air ti be exhausted
bsc class II
bsc class II subtype in which 70% of air is recirculated and 30% is exhausted
bsc class II AI
bsc class II subtype that is similar with bsc class II AI but with higher intake air velocity
bsc class II A2
bsc class II subtype in which 30% of air is recirculated and 70% is exhausted
bsc class II B1
bsc class II subtype in which 100% of air is exhausted
BSC Class II B2
bsc class that is completely exposed with glove ports
bsc class III
provides the highest level of personnel protection ; for extremeley hazardous organism
bsc class III
decontaminating solution for body fluid spills
5.25 NaOCl or 10% chlorine bleach (1:10)
type of radiation used in germicidal lamps for biologic safety cabinets
ultraviolet (<400 nm)
type of radiation used in vein selectors, heat lamps, and lasers
infrared (>700 nm)
used for materials that give off harmful vapors ; provides personnel protection only
fume hood
formely MSDS, a major source of information about chemicals written by manufacturers
SDS
revised formst of SDS consists of how many sections
16 sections
maximum allowable exposure limit within regular shift
threshold limit value
enforcable limit set by OSHA
Permissible exposure limit
absorbs water when exposed to air
hygroscopic
it causes birth defects
teratogen
STANDARD HAZARDS ID SYSTEM BY NFPA ; mnemonic for reactivity
SUVSM
0 stable
1 unstable if heated
2 violent chemical change
3 shock and heat may detonate
4 may detonate
STANDARD HAZARDS ID SYSTEM BY NFPA ; mnemonic for health
NSHED
0 normal material
1 slightly hazardous
2 hazardous
3 extreme danger
4 deadly
STANDARD HAZARDS ID SYSTEM BY NFPA ; color for reactivity
yellow
STANDARD HAZARDS ID SYSTEM BY NFPA ; color for fire/flammability
red
STANDARD HAZARDS ID SYSTEM BY NFPA ; color for special
white
STANDARD HAZARDS ID SYSTEM BY NFPA ; color for health
blue
STANDARD HAZARDS ID SYSTEM BY NFPA ; flash point : FIRE
0 will not burn
1 above 200 F
2 below 200 F
3 below 100 F
4 below 73 F
in fire hazard, these are the actions to take in the event of fire (RACE)
rescue
alarm
contain
extuinguish
mnemonic used when operating fire extinguisher
PASS
pull the pin
aim the nozzle
squeeze trigger
sweeo nozzle
extinguishers used fire class A fire
pressurized water, dry chemical
class b fire extinguishers
dry chemical, carbon dioxide, halon
class c fire extinguishers
dry chemical, carbon dioxide, halon (BEST)
class d fire extinguishers
metal X ( special dry chemical) or sand
in separation of serum and plasma, they are centrifuged at _______ for _____
1000-2000 g for 10 mins
tourniquet application is ____ above the puncture site
3-4 inches
if blood pressure cuff is used, inflate to _____ mmhg
40-60 mmhg
routine antiseptic
70% isopropyl alcohol
antiseptic used for culture
70% alcohol > iodophore, povidone iodone > 70% alcohol
ethanol used for ethanol assay
benzalkonium ( zephiran)
angle between needle and vein for ETS and needle syringe
15-30 degrees
angle between needle and vein for butterfly syringe
less than 15 degrees
not recommended by CLSI due to safety and specimen quality issues
needle syringe
for large volume tubes or large volume syringes used on patients with normal size veins : color code and gauge
20 - yellow
standard needle gauge for routine venipuncture : gauge and color code
21 green
for older children and adult patient with small vein : color gauge
22 black
used on infants and children, difficult veins, or hand veins of adult : color gauge
23 blue
used to collect blood from scalp or tiny veins of premature infants ; prone to hemolysis : color gauge
25 orange
needle length for better control
1- 1.5 inches
needle length for butterly needle
0.5 - 0.75 inches
effect of high temperature on draw volume
decreased draw volume
effect of low temperature on draw volume
increased draw volume
effect of high altitude (>500 ft) on draw volume
decreased draw volume
order of draw in multiple collection using ETS
stop - sterile
light - light blue
red - red plastic
stay - sst
put - pst
green - green
light - lavender
go - gray
uncontrollable factors in preanalytical variables
age, gender, race, and underlying conditions
analytes affected in diurnal variation : increased in the morning
cortisol, ACTH, aldosterone, iron
time collection for cortisol
8 am - peak
4 pm - lower
iron is _____ lower in the affernoon
30% lower
analytes affected in diurnal variation : increased in the afternoon and night
growth hormone
parrathyroid hormone
thyroid stimulating hormone
analytes affected by posture (standing)
increased albumin, cholesterol, calcium
analytes affected by supine to upright position
increased albumin, enzymes, protein bound substance
analytes increased in ambulatory individuals
total protein and ck
analytes affected by exercise
increased creatinine, lactate, potassium, phosphate, ck, ast, lactate dehydrogenase, aldolase
decreased glucose, TAG, cholesterol
analytes requiring fasting
glucose (Fasting plasma glucose and OGTT), triglyceride alone (or as part of lipid profile)
fasting hours for triglyceride
12 - 14 hrs
analytes increased in stress
cathecolamines (epinephrine , norepinephrine), cortisol, ACTH, prolactin
increased analytes in smoking
carbon monoxide, ammonia, BUN (if enzymatic or urease method is used )
effect of IV contamination such as dextrose to glucose measurement
falsely increase
increased analyte due to IV contamination
electrolytes ( Na, K, Cl ), drugs
increased analytes due to hemoconcentration
postassium, lactate, protein, and protein bound substances
increased analyte due to hemolysis
intracellular ions - potassium, magnesium, phosphate, and iron
rbc enzymes - lactate dehydrogenase, ast, acp, choline esterase, and ck (due to adenylate kinase)
intracellular ion greatly affected by hemolysis
potassium
rbc enzyme greatly affected by hemolysis
lactate dehydrogenase
rbc enzyme greatly affected by hemolysis
lactate dehydrogenase
reason why glucose, bilirubin, and lipase are falsely decreased if there is hemolysis
due to hemoglobin interference
resson why sodium is falsely decreased in hemolysis
due to the dilution of extracellular fluid by intracellular fluid
reason why sodium and potassium are falsely elevated if EDTA, citrate, and oxalate are used incorrectly
edta and citrate are present as sodium salts while oxalate is present as potassium salt
enzymes affected by falsely decreased calcium and magnesium
creatine kinase, lactate dehydrogenase, alkaline phosphatase, amylase
magnesium and calcium are importnant _____ to certain enzymes
cofactors
analytes falsely increased if heparin tube is used
Sodium, lithium, ammonia, (depending on additive component used)
analytes falsely decreased if sodium fluoride is used
BUN and Uric acid (enzymatic method)
analyte affected by SST and PST
falsely decreased trace metals, drugs (tricylic antidepressants and antiarrhythmics)
anayltes requiring chilling or ice
ABG, ammonia, lactate, ACTH
analytes requiring anaerobic collection
ABG, ammonia, ACP, ionized calcium
analytes that must be protected from light
bilirubin, porphyrin, carotene, vit A and vit B12
boron-free and can be used with strong acids and alkali
soft glass
aka soda lime glass ; most inexpensive ; releases alkali causing error in certain determinations
flint glass
amber colored glass ; reduces light transmission ; used to contain photosensitive substances
low actinic glass
glass pipette according to design
to contain and to deliver
glass pipette : holds but does not deliver the exact volume
to contain
glass pipette : delivers the exact volume it holds
to deliver
characterized by etched ring / band near the mouth
blow out pipette
allowed to drain by gravity
self draining pipette
examples of transfer pipettes
Volumetric and Ostwald-Folin
Examples of measuring or graduated pipettes
serologic and mohr
To deliver ; self-draining
Volumetric pipette ; Mohr pipette
To deliver ; blow out
Ostwald-Folin pipette ; Serologic pipette
Glass pipette (calibration/graduation mark) : With single capacity mark
Volumetric and Ostwald-Folin
Glass pipette for non viscous samples ; standards
Volumetric
Glass pipette for viscous samples
Ostwald-Folin
Glass pipette for serial dilution ; measuring reagents
Mohr and Serologic pipette
Glass pipette (calibration/graduation mark) : graduated down to tip
Serologic
Glass pipette (calibration/graduation mark) : graduated ; between 2 marks
Mohr
Uses SUCTION to draw sample into a disposable polypropylene tip ; piston does not come in contact with the liquid
Air displacement
Operates like a hypodermic syringe ; tips must be rinsed out
Positive displacement
Pipettes must be calibrated every
6 months
Weight of DISTILLED WATER is delivered ; most accurate
Gravimetric method
Absorbance of COLORED SOLUTION delivered
Spectrophotometric method
Centrifuge type : tubes attain a HORIZONTAL POSITION during SPINNING and a VERTICAL POSITION when at REST ; ____ rpm
HORIZONTAL OR SWINGING BUCKET ; 3000 rpm
Centrifuge type : Tubes are at a fixed angle when rotating ; capable of higher speeds with much less heat build up ; ____ rpm
Fixed-angle or angle-head ; 7,000 rpm
Centrifuge type : used to separate LAYERS of different specific gravities (SG) ; usually REFRIGERATED to counter the heat produced due to friction ; ___ rpm
Ultracentrifuge ; 100,000 rpm
Centrifuge type : For body fluid cell counts ; ___ rpm
Cytocentrifuge ; 200-2000 rpm
Units used for Centrifugation
RPM, RCF(g), Svedberg (s)
Centrifuge QC : parameters
Timer & speed (tachometer), temperature
Centrifuge QC is done every
3 months
Centrifuge QC is done every
3 months
Reagents : HIGH DEGREE of purity suitable for use in most analytical procedures
Analytical reagent grade (American Chemical Society)
Reagents : for specific procedures such as CHROMATOGRAPHY, AAS, IMMUNOASSAY, molecular diagnostics, and standardization techniques
ULTRAPURE GRADES
Reagents : impurity limitations not state ; NOT ACCEPTABLE FOR RESEARCH and LABORATORY techniques
Chemically pure grade
Reagents : Primarily used to manufacture drugs and purity standards may not meet assay requirements
United States Pharmocopeia/ National Formulary Grade
Reagents : should not be used in the clinical lab ; for industrial use only
Technical or commercial grade
Reference material : HIGHLY PURIFIED CHEMICAL that can be measured directly to produce a substance of exact known concentration and purity
Primary standard
ACS Primary standard has purity tolerance value of _______
100 +/- 0.02%
Certified for use in clinical chemistry laboratories
Standard Reference Materials
Purest type of reagent water ; recommended for STANDARD PREPARATION
TYPE I
Reagent water acceptable for most laboratory procedures including reagent preparation
Type II
Reagent water that can be used for some qualitative tests but not for routine analyses and reagent preparation ; water source for the preparation of type I and type II water and for WASHING GLASSWARE
Type III
Max colony count (CFU/mL) : TYPE I
<10 CFU/ml
Max colony count (CFU/mL) : type II
<10^3
UV wavelength
<400 nm
Visible light wavelength
400-700 nm
Infrared wavelength
> 700 nm
Relationship between wavelength and energy
Inversely proportional
Beer-Lambert’s Law
A = abc
Beer-Lambert’s Law
A=abc
a =
Molar Absorptivity
To compute the absorbance value given the % transmittance
A=2-log%T
Distilled water, reagent or sample used to subtract absorbances not due to the analyte of interest ; sets the spectrophotometer to 0 absorbance
Blank
Corrects for absorbance caused by the color of reagents ; used to 0 the instrument before measuring test samples and other blanks
Reagent blank
Used to subtract the intrinsic absorbance cause by hemolysis, icterus, turbidity, or drug interference during sample analysis
Sample blank
Substance of known purity and concentration used to determine the concentration of the unknown analyte
Standard
Solution containing various analyses with known target values ; analyzed with patient samples to monitor analytical performance
Control
Values provided by the manufactured
Assayed control
Values determined by the lab
Unassayed control
Any wavelength outside the band of interest ; detected using cut-off filters
Stray light
Done using GLASS FILTERS and solutions that have known absorbance values
Absorbance check
Type of monochromator : continuous, non linear spectrum better separation of high frequency light
Prism
Type of monochromator : continuous, LINEAR, uniform separation of wavelengths ; most common
Diffraction gratings
Range of wavelengths transmitted ; calculated as width at more than half the maximum transmittance
Bandpass
Simplest type of photodetector
Barrier layer cell
Photodetector that requires external voltage source
Phototube
Photodetector with excellent linearity
Photodiode
Most common and most sensitive photodetector
Photomultiplier
Designed to compensate for variations in intensity of the light source by splitting the light beam from the lamp and directing ONE PORTION to a reference cover and the OTHER to the sample cuvet
Double beam spectrophotometry
Beam splitter ; 2 photodetectors
Double-beam-in- space
Chopper ; 1 photodetector ; excitation energy
Double-beam-in-time
Measurement of the amount of light emitted by excited molecules
Fluorometry
1000 times more sensitive than spectrophotometry
Fluorometry
Number of monochromators used in Fluorometry
2
4 causes of quenching or decreased fluorescence
Increased temp
Prolonged exposure to UV light
Concentrated/ undiluted samples
PH changes and contaminated samples
Measurement of light emission caused by a chemical, biochemical, or electrochemical reaction, and not by photo illumination
Luminometry
Detection of flashes of light using a PM tube and counting of the electrical impulses
Scintillation counting
Crystal scintillation
Gamma counter ; I-125 and I-131
Liquid scintillation
Beta counter ; H-3 and C-14
Measurement of the amount LIGHT BLOCKED
Turbidimetry
Measurement of the amount of light SCATTERED by a suspension of particles
Nephelometry
Involves fragmentation and ionization of molecules using a suitable source of energy followed by separation of the ions by mass-to-charge ratio and counting the number of ions of each type
Mass spectrometry
Involves fragmentation and ionization of molecules using a suitable source of energy followed by separation of the ions by mass-to-charge ratio and counting the number of ions of each type
Mass spectrometry
Non destructive method for determining the structure of organic compound ; used in lipoprotein particle measurement
Nuclear Magnetic Resonance Spectroscopy
Pumps each specimen in a batch through a system of CONTINUOUS tubing at the same rate and is subjected to the same analytic reactions ; significant CARRY-OVER problems and wasteful use of continuously flowing reagents
Continuous flow
These are formed to serve as separating and cleaning media
Air bubbles
Continuous flow : meant for mixing
Coiled tubing/glass coils
Uses centrifugal force to transfer liquids in separate cuvets for measurement ; capable of batch analysis
Centrifugal analysis
Places each sample and accompanying reagents in separate containers ; batch analysis ; random access or stat capabilities
Discrete analysis
Each specimen in a batch enters the analytical process ONE AFTER ANOTHER, and each result or set of results emerges in the same order as the specimens are entered
Sequential analysis
All specimens are subjected to a SERIES of analytical processes at the same time in a PARALLEL fashion
Parallel analysis
Many specimens are GROUPED in the same analytical session ; large number of specimens are in ONE run
Batch analysis
Each specimen is analyzed for a DIFFERENT SELECTION of tests ; capable of analyzing STAT specimens out of sequence on an as-needed basis
Random-access analysis
Requires the reagent TO BE IN A UNIQUE CONTAINER or format provided by the manufacturer
Closed-system analyzer
The operator is ABLE TO CHANGE the parameters related to an analysis and prepare in-house reagents or use reagents from a variety of suppliers
Open-system analyzers
Most commonly used POCT ; use enzymatic methods coupled with photometric or electrochemical detection l should not be used to diagnose DM
Blood glucose monitors (glucometers)
