Module 1: Introduction to Clinical Chemistry Flashcards
Enables analysis which is not
otherwise possible, and enables it to be made faster, more accurately, on smaller
quantities, or more cheaply than by alternative methods.
Instrumentation
consists of efforts to establish and maintain a
climate of continued improvements in the laboratory in order to deliver high-quality services
to health care
Quality management
include appropriate facilities and equipment, adequate training,
PPE, chemical management, SOPs, waste handling, signage, proper laboratory practices and safe working conditions.
Laboratory safety
includes patient preparation,
specimen considerations and variables
Specimen collection and processing
Agreement between your test result value and the true value
Accuracy
The division of a sample into at least two smaller size vials.
Aliquot
The chemical substance being measured in an assay, usually contained in blood or other body fluids.
Analyte
A diagnostic test to measure the concentration or level of a particular analyte.
Assay
A liquid solution containing a combination of chemicals, which control and maintain the pH of any other solution it is added to.
Buffer
A material, generally serum based with an accurately assigned analytical value, used to calibrate diagnostic assays.
Calibrator
A serum based material with assigned target values and acceptable ranges to evaluate the accuracy and reproducibility of a diagnostic assay.
Control
It is used to describe the highest concentration, at which a reaction is still measurable.
Linearity
refers to a material that has been freeze-dried
Lyophilised
Any biochemical compound which plays a key role in the metabolism of the body.
Metabolite
The clear amber liquid which is derived from whole blood that has been collected in the presence of an anticoagulant
Plasma
Refers to the reproducibility of test results and is a measure of how disperse the values are
Precision
The process of detecting errors in any manufacturing or operational system.
Quality Control
A component of a kit used to carry out a chemical reaction to determine levels of different analytes
Reagent
The addition of water to a freeze-dried reagent or control material to return it to its former condition.
Reconstitution
The clear amber liquid that is derived from clotted blood by centrifuging and removing the red blood cells.
Serum
An aqueous solution containing a known level or concentration of analyte that will not change and can be used to calculate diagnostic results.
Standard
Earliest recorded accounts of observations on urine specimens
400 B.C.
made diagnoses by listening to internal body sounds and palpating areas of the body
physicians in Egypt and Mesopotamia
Father of Medicine who began attributing disease to abnormalities in the body fluids.
Hippocrates (Ancient Greece 300 BC)
Hippocrates’ methods of diagnosis
tasting urine, listening to lungs, and observing appearance
described blood in the urine
Ephesus (50 A.D.)
blood in the urine
hematuria
three development in 1600s
invention of microscope, description of blood circulation, protein precipitation in urine through heat and acid
two developments in 1700s
sugar in urine for diabetic patients, yeast used in sugar test
laboratory medicine became more accepted
1850s-1890s
required hospitals to have
an adequately equipped and staffed laboratory
American College of Surgeons in 1918
almost half of US hospitals had laboratories
1920s
developed several methods for determining urine analytes in the 1920s
Otto Folin
renal function associated with ____, ____ and ____
uric acid, NPN, and blood urea nitrogen (BUN)
reagent developed in 1920s for protein determination which is still used today
FolinCiocalteau
In the 1920s, clinical
methods for measuring ___ and ____ in serum were introduced
phosphorus and magnesium
six analytes whose methods for clinical determinations were developed in the 1930s
alkaline phosphatase,
acid phosphatase, serum lipase, serum and urine amylase, and blood ammonia
first used for measuring protein in urine in the 1930s
refractometer
company that played a large part in laboratory science by introducing
the first pH meter to measure the acidity and alkalinity of fluids
Beckman Instruments
two development in 1940s
photoelectric colorimeters and blood vacuum collection tubes
used to to read color
reactions of chemistry analyses
photoelectric colorimeters
two organization important to clinical chemistry founded in the 1940s
College of American Pathologists (CAP) and American Association of Clinical Chemistry
(AACC)
made quality control easier in 1950
Levey and Jennings Shewhart QC
chart
three developments in the late 1950s
method to measure blood triglycerides, AutoAnalyzer by Technicon Corporation, flame photometry
introduced the atomic
absorption spectrophotometer for determination of calcium and magnesium
Perkin-Elmer
late 1950s
laser, mechanical pipetter, Auto Dilutor, disposable needle and syringe, disk storage (IBM), random-access analyzer (DuPont)
provides an actual number that represents the amount of a substance present in the body
Quantitative tests
indicates the presence or absence of specific chemicals
Qualitative tests
tests that are frequently ordered, such as a single test for glucose or a chemistry
profile
routine tests
group of tests performed simultaneously on a patient specimen to provide an assessment of the patient’s general condition
routine chemistry profile/ complete metabolic profile
Tests that are ordered less frequently and might be performed only on certain days even in larger laboratories
special tests
principal uses of biochemical investigations
Diagnosis
Prognosis
Monitoring
Screening
composition of Borosilicate glass
Silica + boron trioxide
Most common type of glass
Borosilicate glass
Thermal property of Borosilicate glass
low coefficient of thermal expansion, can withstand higher temperature gradients and sudden temperature changes
maximum temperature at which a glass can be used without it being damaged
Strain point
strain point of Borosilicate glass
450 to 500 degrees celsius
Optical property of Borosilicate glass
clear and colorless
Chemical property of borosilicate glass
strong chemical resistance (higher than metals)
chemicals that Borosilicate glass is not resistant to
hydrofluoric acid, very hot phosphoric acid, alkaline solutions
Borosilicate is highly resistant to
water, neutral and acid solutions, concentrated acids and chlorine, bromine, iodine and organic matters
composition of Alumina-silicate glass
Aluminum oxide + high silica content
has greater chemical stability
and higher maximum operating temperature than borosilicate glass
Alumina-silicate glass
use of Alumina-silicate glass
high precision analytical work
properties of Alumina-silicate glass is comparable to
fused quartz
Alumina-silicate glass is strengthened ____ rather than ___
chemically, thermally
composition of Vycor glass
96% silica (similar to fused quartz)
strain point of vycor glass
900 degrees celsius continuously, 1200 Intermittently
vycor glass is resistant to
drastic heat shock and extreme chemical treatments
Most inexpensive glass with excellent chemical and physical properties
soda-lime glass
most common use of soda-lime glass in the clinical lab
pipettes
glassware that protects light sensitive chemical compounds from alteration
Low actinic glass
glassware for one time use only
Disposable glassware
three advantages of plastic ware
less expensive, unbreakable, preferred for alkali solutions
four disadvantages of plastic ware
surface constituents can leach into solution, permeable to water vapor, can evaporate, can absorb dyes, stains and proteins
____ cannot be used for plasticware
high performance liquid chromatography
properties of polystyrene
70 C temp limit, clear, non autoclavable, rigid
uses of polystyrene
Disposable plastic ware
Properties of Conventional/ High density Polyethylene
80 C, translucent, non autoclavable, flexible
used for all purposes like reagent bottles, droppers
Polyethylene
properties of Linear/ Low Density Polyethylene
130 C, opaque, autoclavable
with caution, rigid
most commonly used plastic ware in the lab
Polypropylene
properties of polypropylene
135 C, translucent, autoclavable, rigid
uses of polypropylene
Screw-cap closure bottles
properties of Tygon
95 C, translucent, autoclavable, flexible
use for tygon
tubings
properties of Teflon (Fluorinated Ethylene Propylene/ Polytetrafluoroethylene)
205 C, Clear to translucent, autoclavable, flexible but easily scratched/warped
used for stopcocks, wash bottles, and beakers for
cryogenic experiments
Teflon
properties of polycarbonate
135 C, very clear and shatter proof, autoclavable, rigid (sterilizing reduces mechanical strength)
used for all purposes like large reagent containers, graduated cylinders and centrifuge tubes
Polycarbonate
properties of Polyvinyl Chloride
70 C, clear, non autoclavable, rigid
used to make bottles
polyvinyl chloride
properties of PVC for tubing
120 C, clear, autoclavable, flexible
properties of polyallomer
130 C, translucent, autoclavable, moderately flexible
properties of polysulfone
165 C, clear, autoclavable, rigid
plasticware to use for acids, aldehydes, ketones, ethers, hydrocarbons, essential oils
Polystyrene
Plasticware to use for alcohols and bases
polystyrene but only within 24 hours
plasticware NOT to use for aldehydes, amines, ethers, hydrocarbons, and essential oils
Polyethylene and polypropylene
plasticware NOT to use for lubricating oil and silicone
Conventional Polyethylene
Resin possessing chemical resistance to almost all chemicals in clinical lab
Teflon
three advantages of Teflon
Anti-adhesive, non wet-table surface, suitable for cryogenic experiments
temperature capacity of Teflon
-270℃ to 255℃
Plasticware susceptible to damage by most chemicals
Polycarbonate
Polycarbonate is resistant to (4) ___ for a long time
water, aqueous salts, food, and inorganic acids
Five grades of reagent purity
- Analytic reagent (AR)
- Ultrapure/ chemically pure
- United States Pharmacopeia (USP) and National Formulary (NF)
- Chemically Pure (CP)
- Technical or commercial grade
purity grades are established by
American Chemical Society (ACS)
Very high purity that is suitable use in most analytical procedures
Analytic reagent (AR)
AR should be labeled with: (4)
- percentage of impurities
- initials AR or ACS
- “For laboratory use”
- “Standard-Grade Reference Materials”
Like AR but have additional purification steps (higher grade)
Ultrapure/ chemically pure
uses of Ultrapure/ chemically pure grade reagents
Chromatography
Atomic absorption immunoassays
Molecular diagnostics
Standardization
Ultrapure/ chemically pure are labeled with (2)
HPLC or Chromatographic
Used to manufacture drugs and not for laboratory analysis
United States Pharmacopeia (USP) and National Formulary (NF)
only limitation of USP and NF grades
should be non-injurious to individuals
Less pure grade chemicals whose impurity limitations are not stated, and preparation is not uniformed
Chemically Pure (CP)
Chemically Pure (CP) is not recommended for reagent preparation unless:
a) has further purification
b) has reagent blank
Used primarily in manufacturing and should never be used in clinical laboratory
Technical or commercial grade
four grades of organic reagents
Spectroscopic Grade
Chromatographic Grade
Reagent grade
Chemically Pure
Purity levels attained by spectrophotometric procedures
Spectroscopic Grade organic reagents
Minimum purity of 99% determined by gas chromatography
Chromatographic Grade
Certified to contain impurities below certain levels established by ACS
Reagent grade (ACS)
Approaches purity level of reagent grade chemicals
Chemically Pure
Materials with a specific, defined characteristic that serves a comparative value for analyses for quality assurance scheme
Reference materials
Three standards for reference materials
- Primary Standard
- Standard Reference Material
- Secondary Standard
Highly purified chemical
which is used to produce a substance of EXACT known concentration. This is not used in the laboratory as biologic constituents are unavailable within these limits.
Primary standard
ACS purity tolerance for Primary standard
100 ± 0.02%
Primary standard in the clinical chemistry laboratory in place of ACS primary standard.
Standard Reference Material (SRM)
developed and assigned a value to SRM after careful analysis
National Institute of Standards and Technology (NIST)
Used to verify calibration or accuracy/bias assessments, to produce calibrator and standards and as reference for comparison of commercially obtained standards and reagents
Standard Reference Material (SRM)
Label to be found in Standard Reference Material (SRM)
“Traceable to NIST”
Lower level of purity
Secondary standard
The concentration of a secondary standard is determined by comparison with
primary standard
Secondary standard depends not only on composition which cannot be directly determined but also on
analytic reference method
Secondary standard manufacturers are required to list
the SRM or primary standard used
most frequently used reagent in the lab
water
six processes in the purification of water
- prefiltration
- distillation
- deionization
- reverse osmosis
- ultrafiltration and nanofiltration
- UV oxidation and ozone treatment
Remove particulate matter from municipal water supplies before any additional treatment
Prefiltration
Four types of filtration cartridges
Glass
Cotton
Activated charcoal
Submicron filters
preferable in filtration of hard water
glass or cotton
contents of hard water
Ca, Fe, and other dissolved elements
Use of activated charcoal filter
adsorption of organic material and Cl
pore size of submicron filters
< 0.2 mm
Better suited after distillation, deionization and reverse osmosis treatment
Submicron filters
Removes any substances larger than pore, including bacteria
Submicron filters
Removes microbiological organism and minerals iron, magnesium, and calcium
Distillation
Distillation does not remove
volatile impurities (CO2, Cl, NH3)
Distilled water meets specification for
type II and III water
Removes substances that can ionize
Deionization
deionization does not remove
organic substances and substances that do not ionize
Deionization passes water through
cation-exchange or an anion-exchange resin
Deionization replaces removed ions with
OH- and H+ ions
Uses anion resin followed by cation resin
Two-bed system
Uses pressure to force water through a semipermeable membrane
Reverse osmosis
example of semipermeable membrane
cellulose acetate
Reverse osmosis removes
Approximately 90% dissolved solids
98% organic impurities, insoluble matter, microbiological organisms
10% ionized particles
Reverse osmosis does not remove:
Dissolved gases
Excellent in removing particulate matter, microorganisms (pyrogens or endotoxin)
Ultrafiltration and Nanofiltration
cleaves many ionizing organics, destroys bacteria but may leave residual products
Ultraviolet oxidation and ozone treatment
UV radiation wavelength
biocidal wavelength 254 nm
Two classifications of water purity
Conventional Classification (National Committee for Clinical Laboratory Standards) CLSI (Clinical and Laboratory Standards Institute)
Grades of water based on Conventional Classification (National Committee for Clinical Laboratory Standards)
Type I, Type II, and Type III
Purest type of water used for procedures that require maximum water purity
Type I reagent water
Five uses of Type I reagent water
Preparation of standard solutions, buffers and controls Quantitative analytical procedures Electrophoresis Toxicology screening tests HPLC
Use immediately after produced, should not be stored
Type I reagent water
Used for general lab test that do not require type I water
Type II reagent water
Uses of Type II reagent water
Qualitative chemistry procedures
hematology
immunology
microbiology
Also known as sutoclave wash water
Type III reagent water
Can be used as water source for preparation of type I and type II
type III
uses of Type III reagent water
washing and rinsing labware
Maximum colony count (CFU/mL) for Type I water
10
Maximum colony count (CFU/mL) for Type II water
1000
Maximum colony count (CFU/mL) for Type III water
not specified
pH of type I and type II water
not specified
pH of type III water
5.0-8.0
Maximum silicate (mg/L SiO2) content for Type I
0.05
Maximum silicate (mg/L SiO2) content for Type II
0.1
Maximum silicate (mg/L SiO2) content for Type III
1.0
Minimum resistivity
MΩ/cm at 25℃ of Type I water
10
Minimum resistivity
MΩ/cm at 25℃ of Type II water
1.0
Minimum resistivity
MΩ/cm at 25℃ of Type III water
0.1
6 grades of water according to CLSI classification
Clinical Laboratory Reagent water (CLRW) Special Reagent Water (SRW) Instrument Feed water Water supplied by method manufacturer Autoclave and Wash water Commercially bottled purified water
Maximum Microbiological content of CLRW
10 CFU/ mL
Minimum Resistivity at 25 C of CLRW
> 10 MΩ/ cm
Maximum Silicate of CLRW
0.05 mg SiO2/L
Particulate matter of CLRW
passed through 0.2 μm filter
organic content of CLRW
< 500 ppb, through activated carbon
used for HPLC
Special Reagent Water
Intended for internal rinsing, dilution, and water bath functions of automated instruments
Instrument Feed water
Supplied for use as diluent or reagent as described by for product labeling
Water supplied by method manufacturer
Feed water for autoclaves and automatic lab dishwashers with heat drying cycles, previously referred to as type III water
Autoclave and Wash water
Must be validated for acceptable performance in test procedure to be used in
Commercially bottled purified water
Help in getting perfect measurement of fluids
pipette
three types of classifications of pipettes
according to design
according to drainage characteristic
according to type
two types of pipettes according to design
To contain (TC) To deliver (TD)
Holds particular volume but does not dispense that exact volume
To Contain (TC)
Dispenses the exact volume indicated
To Deliver (TD)
Two types of pipette according to drainage characteristic
Blowout
Self-draining
The last drop of liquid should be expelled into the receiving vessel using rubber stopper/ rubber bulb or pipettol
Blowout
indicates that a pipette is blowout
etched ring or two small, close close continuous rings
Content of pipet drained by gravity
Self-draining
pipettes according to type
Measuring graduated pipet
Transfer pipet
Automatic pipet
Has many uniform graduations and can dispense different volumes
Measuring graduated pipet
two types of measuring graduated pipet
Mohr pipette and Serological pipette
Graduation ends BEFORE the tip
Mohr pipette
qualities of a Mohr pipette
Self draining
Smaller orifice
Has graduation marks until the tip
Serological pipette
qualities of a Serological pipette
Blowout
Have larger orifice and thus drain faster
Transfers a known volume of liquid and have no subdivisions
Transfer pipet
two types of transfer pipet
Ostwald Folin
Volumetric
the bulb closer to the tip to use for viscous fluids like blood
OSTWALD-FOLIN
Ostwald Folin drainage characteristic
Blowout
Cylindrical bulb at the center joined at both ends to the narrow glass tubing which is used for dilute aqueous solutions.
VOLUMETRIC
Volumetric pipette drainage characteristic
self-draining
used to transfer small quantities of liquids without calibration marks and consideration for volume
Pasteur Pipet
Most routinely used pipet
automatic pipet
three types of classification of automatic pipettes
Based on delivery volume amount, total volume capacity, mechanism
Two types of pipettes based on delivery volume amount
Fixed volume
Variable volume
Two types of pipettes based on total volume capacity
Micropipette: <1mL
Macropipette >1mL
three types of pipettes based on mechanism
Air-displacement
Positive displacement
Dilutors/dispensers
Relies on piston for creating suction to draw the sample into disposable tip where but it does not come in contact with the solution
Air-displacement
has plastic disposable tip
Air-displacement
Operates by moving the piston in the pipet tip or barrel, much like a hypodermic syringe
Positive displacement
disadvantage of positive displacement
carryover or contamination due to tips not being removable
obtain the liquid from a common reservoir and dispense it repeatedly
Dilutors/dispensers
two ways to calibrate a pipette
Gravimetric method
Photometric method
materials in gravimetric method calibration
deionized, distilled water
calibrated analytical balance
class 2 weights
allowable percentage error of gravimetric method
0.5%
materials in photometric method
spectrophotometer
Potassium dichromate
Two components of a quantitative lab result
number & unit
two systems of measurement
conventional system (metric and US standard) and Systeme Internatiol d’ Unites
what type of unit: m, kg, s
basic units
what type of unit: m/s2, m3
derived unit
what type of unit: grams, liters, hours
supplemental unit