COMPREHENSIVE EXAM Flashcards
- Resistant to most chemicals
- Used for pipet tips, test tubes
Polypropylene
-Most excellent temperature tolerance and
unparalleled chemical resistance
Teflon
- Clear; stronger than polypropylene
(resistant to shattering) and has better
temperature tolerance - Chemical resistance is not as good
- Used for centrifuge tubes and graduated
cylinders
Polycarbonate
Types of Pipette
Volumetric
Ostwald-Folin
Serologic
Mohr
Type of Reagent Water
Type I
Type II
Type III
- Purest type
- Recommended for procedures that require maximum purity and
minimal interference; for standard preparation
Type I
- Acceptable for most laboratory procedures including REAGENT PREPARATION
Type II
- Can be used for some qualitative tests but not for routine analyses and reagent preparation
- Water source for the preparation of Type I or II water and for
washing glass
Type III
- Contain everything you need to know about a chemical reagent
- Must be available for reference by the staff
MSDS (Material Safety Data Sheets)
- Allowable exposure value during an 8-hour shift
- Inversely proportional to toxicity
TLV (Threshold Limit Value)
Radiation type with a wavelength of <400nm
Ultraviolet
Radiation type with a wavelength of >700nm
Infrared
Radiation type with a wavelength of 400-700nm
Visible Spectrum
number of moles of solute per liter (L) of
solution
Molarity
number of moles of
solute per kilogram
(kg) of solvent
Molality
number of equivalents
weights of solute per
liter (L) of solution
Normality
Conversion factor of Glucose
0.05551
Conversion factor of BUN
0.357
Conversion factor of Uric Acid
0.0595
Conversion factor of Cholesterol
0.02586
Conversion factor of Triglycerides
0.01126
Conversion factor of Creatinine
88.4
Conversion factor of Bilirubin
17.1
Conversion factor of Protein
10
- average or arithmetic mean
- commonly used in QC as a measure of center
Mean
- Central value or midpoint of a data set after the values have been ranked
or ordered
Median
- most frequently occurring value in a data set
- can be multimodal, bimodal, or no mode
Mode
68% of values fall within
1SD
95% of values fall within
2SD
99% of values fall within
3SD
- Ability of a test to detect a given disease
or condition - The proportion of individuals who have the disease who also tested positive
Diagnostic sensitivity
- Ability of a test to detect the absence of
a given disease or condition - The proportion of individuals who do not
have the disease which also tested
negative
Diagnostic specificity
- The probability that a positive test indicates
disease - The proportion of individuals who tested
positive and who truly have the disease
Positive predictive value
- The probability that a negative test indicates
absence of disease - The proportion of individuals who tested
negative and don’t have the disease
Negative predictive value
- Ability of a method to detect the smallest concentration of an analyte
Analytical sensitivity
Ability of a method to detect only the analyte of interest
Analytical specificity
- Due to chance or an
unpredictable cause - Affects precision
- Affects few control
observations or samples
Random Error
- influences observations consistently
in one direction - affects accuracy
- persists until troubleshooting is
performed - affects all observations in a run
- shift and trend
Systematic Error
-Data points are distributed symmetrically around the mean (bell curve) with
most values close to the center; mean, median, and mode are identical
- 95% confidence limit: desired; control observations should fall within this limit
GAUSSIAN/NORMAL DISTRIBUTION
Examples of Anticoagulant Additives
EDTA
Citrate
Oxalate
Heparin
Examples of Clot Activators Additives
Silica
Celite
Diatomite
Thrombin
(most commonly used anticoagulant in CC)
Heparin
Example of an Antiglycolytic agent
Sodium fluoride
Prevents glycolysis
Primarily for glucose but
may also be used for
lactate and ethanol
Inhibits urease and uricase
(may falsely decrease BUN
and uric acid levels
respectively)
Sodium fluoride
Considered the standard venipuncture needle for routine venipuncture on patients with normal veins or for syringe blood culture collection
21 gauge
Measurement of the amount of light from a specific wavelength of the electromagnetic wavelength
SPECTROPHOTOMETRY
The concentration of a substance is directly proportional to the amount of light absorbed and is inversely proportional to the logarithm of transmitted light
Beer’s Law (Beer-Lambert’s Law)
- Distilled water, reagent, or sample used to subtract absorbances not due
to the analyte of interest - Sets the spectrophotometer to 0 absorbance
Blank
The substance of known purity and concentration used to calibrate an assay
method or determine the concentration of the unknown analyte (for a
single analyte only)
Standard/Calibrator
A solution containing various analytes with known target values
Control
provides the light that the analyte in the sample will absorb
Light source
ensures that the light that enters the monochromator only comes from the
light source; prevents stray light
Entrance slit
selects a specific wavelength of the light emitted by the source (makes
polychromatic light monochromatic)
Monochromator
- further prevents stray lights and controls the bandpass
- ensures that only a narrow fraction of the spectrum will strike the sample
Exit slit
- Should be transparent to the wavelength of interest
- Light should pass through and not absorb any part of it
- Can be quartz, plastic, or glass.
Cuvet
- Light transmitted is the light which was not absorbed
- Transforms light into an equivalent amount of electrical energy which will be quantified by the meter (part of the read-out device)
- Most commonly used and most sensitive: photomultiplier
Photodetector/Photomultiplier
Principle: Measurement of the amount of light emitted by excited molecules
FLUOROMETRY
Principle: Measurement of light emitted by a chemical reaction; involves oxidation of an organic compound catalyzed by an enzyme, a metal, or hemin
CHEMILUMINESCENCE
most commonly used POCT
Blood glucose monitors (glucometers)
Used for determining electrolytes and blood gases
ELECTROCHEMICAL TECHNIQUES
Hypoglycemia: plasma glucose level
< 50 mg/dL
Panic value for hypoglycemia
<40mg/dL
Whipple’s triad of hypoglycemia
Symptoms of hypoglycemia
Low plasma glucose level
Relief of symptoms following correction
- autoimmune or idiopathic beta cell destruction leading to absolute insulin
deficiency - Insulin-dependent
Type I DM
- insulin resistance with progressive insulin deficiency
Type 2 DM
- glucose intolerance during pregnancy that disappears post-partum but may convert to type 2 DM in 30-40% of cases within 10 years
- due to metabolic and hormonal changes
Gestational DM
Random Blood Sugar Diagnostic Criteria for Diabetes Mellitus
> 200mg/dL + symptoms
Fasting Blood Sugar Diagnostic Criteria for Diabetes Mellitus
> 126 mg/dL
2-hr PG (OGTT) Diagnostic Criteria for Diabetes Mellitus
> 200 mg/dL
HbA1C Diagnostic Criteria for Diabetes Mellitus
> 6.5%
Chemical Method for Glucose Measurement
Copper Reduction
Ferric Reduction
Condensation
Enzymatic Method for Glucose Measurement
Glucose Oxidase
Hexokinase
due to a deficiency of the enzyme GALT
Galactosemia
Enzyme deficient of Ia (Von Gierke)
Glucose-6-phosphatase
Are the largest lipoproteins and have the lowest density.
Chylomicrons
Carries endogenous triglycerides synthesized in the liver.
VERY-LOW-DENSITY LIPOPROTEIN (VLDL)
A transitional form, as it is formed from VLDL and then further modified in the liver to LDL.
INTERMEDIATE-DENSITY LIPOPROTEIN (IDL)
The body’s major cholesterol carrier and transports a large amount of endogenous cholesterol. Known as “bad cholesterol,” LDL is easily taken up by cells, so elevated levels are associated with increased risk for
atherosclerosis (atherogenic).
LOW-DENSITY LIPOPROTEIN (LDL)
Is also known as “good cholesterol.”
HIGH-DENSITY LIPOPROTEIN (HDL)
Floating beta-lipoprotein
Migrates along with beta-lipoprotein but floats in ultracentrifugation
β-VLDL
Sinking pre-beta lipoprotein
Lp(a)
also known as Bassen-Kornzweig Syndrome
Abetalipoproteinemia
Abetalipoproteinemia is also known as
Bassen-Kornzweig Syndrome
Chemical methods for cholesterol
Abell Kendall method
Modified Abell-Kendall
GCMS (current reference method)
Friedewald equation
VLDL = TG/5 (mg/dL) or 2.175 (mol)
Most abundant NPN
UREA
BUN to Urea
Multiply by 2.14
Urea to BUN
Divide by 2.14
Reference method of Urea
Isotope Dilution Mass Spectrometry (IDMS)
Very high plasma urea concentration accompanied by renal failure
UREMIA/UREMIC SYNDROME
Constitutes 5% of total plasma NPNs
CREATININE (5%)
Creatinine Chemical Method
Jaffe Reaction
Smallest in concentration; only comprises 0.2% of total plasma NPNs
AMMONIA (0.2%)
A major contributor to osmotic or oncotic pressure (most abundant plasma
protein)
ALBUMIN
Synthesized during gestation in the yolk sac and liver of the fetus, peaking at 13 weeks and declining at 34 weeks.
α – Fetoprotein
Positive acute phase reactant (APR)
Binds free hemoglobin to preserve iron
Haptoglobin
Positive acute phase reactant; has oxidase activity
Copper binding protein
Ceruloplasmin
Transports ferric form of iron
Transferrin
The most sensitive positive acute phase reactant
Enhances phagocytosis in inflammatory disease
Most useful nonspecific marker of inflammation
C-Reactive Protein