Medical Technology Board Examination Review Notes Must Know (Rodriguez)

Quality Control
Practicability	Method is easily repeated
Reliability	Maintain accuracy and precision
Intralab/Interlab QC	Daily monitoring of accuracy and precision
Interlab/External QC	Proficiency testing (Reference lab) Long-term accuracy Difference of >2: not in agreement w/ other lab
QC materials	Available for a min. of 1 yr
Bovine control materials	Preferred (Human: biohazard) Not for immunochem, dye-binding and bilirubin
Matrix effect	Improper product manufacturing Unpurified analyte Altered protein
Precision study	First step in method evaluation
Nonlab. personnel	29% of errors (lab results)
SD	Dispersion of values from the mean
CV	Index of precision Relative magnitude of variability (%)
Variance	SD2 Measure of variability
Inferential statistics	Compare means or SD of 2 groups of data
T-test	Means of 2 groups of data
F-test	SD of 2 groups of data
Cumulative Sum Graph (CUSUM)	V-mask Earliest indication of systematic errors (trend)
Youden/Twin Plot	Compare results obtained from diff. lab
Shewhart Levey-Jennings Chart	Graphic representation of the acceptable limits of variation
Trend	Gradual loss of reliability Cause: Deterioration of reagents (Systematic error)
Shift	Values: one side or either side of the mean Cause: Improper calibration (Systematic error)
Outliers	Values: far from the main set of values Highly deviating values Random or systematic errors
Kurtosis	Degree of flatness or sharpness
Precision	Random error
Accuracy	Systematic error
Random error (Imprecision; Indeterminate)	Causes: -Mislabeling -Pipetting error -Improper mixing of sample and reagents -Voltage/Temperature fluctuation -Dirty optics Parameters: SD and CV
Systematic error (Inaccuracy/Determinate)	Causes: -Improper calibration -Deterioration of reagents -Contaminated solution -Sample instability/unstable reagent blanks -Diminishing lamp power -Incorrect sample and reagent volume Parameter: Mean
Multirule Shewhart procedure	Control rules + Control chart
Test method	Westgard: at least 40 samples
Reference method	Westgard: preferably 100 samples
Analytical Run	Control and patient specimens assayed, evaluated, and report together
Physiologic Limit	Referred to as absurd value
POCT	Performed by nonlab personnel
Quality Assurance	Tripod: Program development Assessment and monitoring Quality improvement
Quality Patient Care	Test request forms, clear instruction for patient prep., specimen handling…
Reference Range/ Interval Range/ Reference Values	At least 120 individuals should be tested in each age and sex category
Analytical Methods
Wavelength	Distance bet 2 successive peaks (nm) Lower frequency = Longer wavelength (Ex. Red) Higher frequency = Shorter wavelength (Ex. Violet)
Spectrophotometric meas.	Meas. light intensity in a narrower wavelength
Photometric measurement	Meas. light intensity w/o consideration of wavelength Multiple wavelength (uses filter only)
LASER	Light Amplification by Stimulated Emission of Radiation Light source for spectrophotometry
Visible region	Tungsten light bulb Mercury arc
UV	Deuterium lamp Mercury arc Xenon lamp Hydrogen lamp
IR	Merst glower Globar (Silicone carbide)
Stray light	Wavelength outside the band Most common cause of loss of linearity
Diffraction gratings	Most commonly used monochromator Cutting grooves
Prisms	Rotatable
Nickel sulfate	Prevents stray light
Cutoff filter	Anti-stray light
Bandpass	½ peak transmittance
Alumina silica glass cuvet	Most commonly used cuvet
Quartz/plastic cuvet	UV
Borosilicate glass cuvet	Strong bases
Photodetector	Converts transmitted light into photoelectric energy
Barrier layer cell/ photocell/ photovoltaic cell	Simplest detector No external voltage For filter photometers
Phototube	Contains anode and cathode Req external voltage
Photomultiplier tube	Most common type Most sensitive UV and visible region
Galvanometer/Ammeter	Meter or read-out device
Absorbance	A = abc (a = absorptivity; b = length of light (1cm); c = concentration) A = 2 – log%T
Double beam spectro.	Splits monochromatic light into two components: One beam à sample One beam à reference soln or blank (corrects for variation in light source intensity)
Double-beam in space	2 photodetectors (sample beam and reference beam)
Double-beam in time	1 photodetector Monochromatic light à sample cuvet and reference cuvet
Dydimium filter	600 nm
Holmium oxide filter	360 nm
Reagent blank	Color of reagents
Sample blank	Optical interference (Hgb)
FEP	Meas. light emitted by a single atom burned in a flame Principle: Excitation Lt. source and cuvette: Flame For excited ions (Na+, K+)
Cesium and Lithium	Internal standards (FEP) Correct variations in flame
Lithium	Preferred internal std Potent antidepressant
AAS	Meas. light absorbed by atoms dissociated by heat Principle: Dissociation (unionized, unexcited, ground state) Lt. source: Hollow-cathode lamp For unexcited trace metals (Ca++ and Mg++) More sensitive than FEP
Atomizer (nebulizer)	Convert ions à atoms
Chopper	Modulate the light source
Lanthanum/Strontium chloride	Complex with phosphate Avoid calcium interference
Volumetric (Titrimetric)	Unknown sample is made to react with a known solution in the presence of an indicator
Turbidimetry	Light blocked Meas. abundant large particles (Proteins) Depend on specimen concentration and particle size
Nephelometry	Meas. amt of Ag-Ab complexes Scattered light Depends on wavelength and particle size
Electrophoresis	Migration of charged particles in an electric field
Iontophoresis	Migration of small charged ions
Zone electrophoresis	Migration of charged macromolecules
Endosmosis	Movement of buffer ions and solvent relative to the fixed support Ex: gamma globulins
Cellulose acetate	Molecular size
Agarose gel	Electrical charge
Polyacrylamide gel	Charge and molecular size 20 fractions (ex. isoenzymes)
Electrophoretic mobility	Directly proportional to net charge Inversely proportional to molecular size & viscosity of the supporting medium
Isoelectric focusing	Molecules migrate through a pH gradient pH = pI For isoenzymes: same size, different charge
Densitometry	Scan & quantitate electrophoretic pattern
Capillary electrophoresis	Electro-osmotic flow
Southern blot	DNA
Northern blot	RNA
Western blot	Proteins
Chromatography	Separation by specific differences in physical-chemical characteristics of the different constituents
Paper chromatography	Fractionation of sugar and amino acid Sorbent: Whatman paper
TLC	Screening: Drugs
Retention factor (Rf) value	Relative distance of migration from the point of application Rf = Distance leading edge of component moves                Total distance solvent front moves
Gas chromatography	Separation of steroids, barbiturates, blood, alcohol, and lipids Volatile compounds Specimens à vaporized Mobile phase: Inert gases
Gas Solid chromatography	Differences in absorption at the solid phase surfaces
Gas Liquid chromatography	Differences in solute partitioning between the gaseous mobile phase and the liquid stationary phase
Mass Spectrometry	Fragmentation and ionization
GC-MS	Gold standard for drug testing
MS/MS	Detect 20 inborn errors of metabolism from a single blood spot
HPLC	Most widely used liquid chromatography Fractionation of drugs, hormones, lipids, carbohydrates and proteins
Hydrophilic gel	Gel filtration Separation of enzymes, antibodies and proteins Ex: Dextran and agarose
Hydrophobic gel	Gel permeation Separation of triglyceride and fatty acid Ex: Sephadex
Ion exchange chromatography	Separation depends on the sign and ionic charge density
Partition chromatography	Based on relative solubility in an organic solvent (nonpolar) and an aqueous solvent (polar)
Affinity chromatography	For lipoproteins, CHO and glycated hemoglobins
Adsorption chromatography	Based on differences between the adsorption and desorption of solutes at the surfaces of a solid particle
Fluorometry/Molecular Luminescence Spectro.	Det. amt. of lt. emitted by a molecule after excitation by electromagnetic radiation Lt. sources: Mercury arc and Xenon lamp (UV) Lt. detector: Photomultiplier tubes 2 monochromators: Primary filter – selects wavelength absorbed by the solution to be measured Secondary filter – prevents incident light from striking the photodetector Sensitivity: 1000x than spectro
Quenching	Major disadvantage of fluorometry pH and temperature changes, chemical contaminants, UVL changes
Instrumentation
Borosilicate glasswares	For heating and sterilization Ex: Pyrex and Kimax
Boron-free/Soft glasswares	High resistance to alkali
Corex (Corning)	Special alumina-silicate glass Strengthened chemically than thermally 6x stronger than borosilicate
Vycor (Corning)	For high thermal, drastic heat and shock Can be heated to 900OC
Flint glass	Soda-lime glass + Calcium, Silicon, Sodium oxides Easy to melt For making disposable glasswares
TD: To deliver	Exact amount
TC: To contain	Does not disperse the exact volume
Blowout	w/ etched rings on top of pipet
Self-draining	w/ o etched rings Drain by gravity
Transfer pipet	Volumetric: for non-viscous fluid; self-draining Ostwald folin: for viscous fluid; w/ etched ring Pasteur: w/o consideration of a specific volume Automatic macro-/micropipets
Graduated or measuring pipet	Serological: w/ graduations to the tip (blowout) Mohr: w/o graduations to the tip (self-draining) Bacteriologic Ball, Kolmer and Kahn Micropipettes: <1 mL
Micropipettes	TC pipets: Sahli-Hellige pipet Lang-Levy pipet RBC and WBC pipets Kirk and Overflow pipets
Air displacement pipet	Piston: suction Disposable tip
Positive displacement pipet	Piston à barrel (like a hypodermic syringe)
Dispenser/Dilutor pipet	Liquid: common reservoir à dispense repeatedly
Distilled H2O	Calibrating medium for TD pipettes
Mercury	Calibrating medium for TC pipettes
Acid dichromate (H2SO4 + K2Cr2O4)	Cleaning solution for glasswares
Continuous flow analyzer	Common reaction vessel Air bubbles: separates and cleans Glass coil: mix Examples: “STS” Simultaneous Multiple Analyzer (SMA) Technicon Autoanalyzer II SMAC
Centrifugal analyzer	Acceleration and deceleration of the rotor Advantage: Batch analysis Examples: “RICC” Cobas-Bio (Roche) IL Monarch CentrifiChem RotoChem
Discrete Analyzer	Most popular Req. vol: 2-6 μL Uses positive-displacement pipets Run multiple-tests-one-sample-at-a-time Random access capability (STAT) Examples: Vitros Dimension Dade Beckman ASTRA System (4 & 8) Hitachi Bayer Advia Roche Cobas Integra 800 Roche Analytics P Module Automated Clinical Analyzer (ACA) Star (Dade) Dupont ACA Abbott ABA-100 Bichromatic Analyzer ABA-200 VP Analyzer American Monitor KDA Olympus Demand
Thin-Film Analyzers (Dry slide technology)	4 or 5 layers: -Spreading layer -Scavenger layer - Ascorbate Oxidase -Reagent layer -Indicator layer -Support layer Colored reaction à Reflectance spectrophotometry Examples: “KV2(75)” Kodak Ektachem Vitros 750XRC Vitros 550XRC
Carry over	Transport of quantity of analyte or rgt from one specimen rxn into another, and contaminating a subsequent one
Batch testing	All samples loaded at the same time Single test is conducted on each sample
Parallel testing	One specimen More than one test is analyzed
Random access testing	Any sample Any test Any sequence STAT
Sequential testing	Multiple tests analyzed one after another on a given specimen
Open reagent system	System other than manufacturer’s reagents can be utilized for measurement
Closed reagent system	The operator can only use the manufacturer’s reagents
Patient Preparation
Exercise	Increased: GU2FT C2L3A5P2 GH Urea Urinary protein (Proteinuria) Fatty acid Testosterone CPK (muscle) Creatinine (muscle) Lactate LH LD (muscle) ACP Aldolase (muscle) AST ALT Ammonia Pyruvate Prolactin Decreased: Glucose
Fist clenching	Increased: “LPP” Lactate Potassium Phosphate
Fasting	8-16 hours: Glucose Lipids Lipoproteins Increased: Bilirubin (48 hours) Triglyceride (72 hours)
Basal state collection	Glucose Cholesterol Triglyceride Electrolytes
Diet	Increased: “GLUC2H” Glucose Lipids Urea (High protein diet) Caffeine: increases glucose Catecholamines 5-HIAA (From Serotonin)
Turbidity/Lactescence	Triglyceride >400mg/dL
Icterisia	Bilirubin: 25.2 mg/dL
Icteric samples	Interfere with: "TACGu” Total Protein Albumin Cholesterol Glucose
Upright/supine (lying) position	Preferred position Patient should be seated/supine at least 20 mins before blood collection to prevent hemodilution or hemoconcentration
Supine à Sitting/Standing	Vasoconstriction à Reduced plasma volume Increased: “ECA” Enzymes Calcium Albumin
Sitting à Supine	Hemoconcentration Increased: “P(u)BLIC” Proteins BUN Lipids Iron Calcium
Standing à Supine	Hemodilution Decreased: “TLC” Triglycerides Lipoproteins Cholesterol
Prolonged standing	Increased: K+ (muscles)
Prolonged bedrest	Decreased: Albumin (Fluid retention)
Tourniquet	Recommended: 1 minute application
Prolonged tourniquet app.	Hemoconcentration Anaerobiosis Increased: “C2LEA2K” Calcium Cholesterol Lactate Enzymes Ammonia Albumin K+
Tobacco smoking (Nicotine)	Increased: “TUNG2C3” Triglycerides Urea Nonesterified fatty acid Glucose GH Catecholamines Cortisol Cholesterol
Alcohol ingestion	Increased: “THUG” Triglycerides Hypoglycemia (chronic alcoholism) Uric acid/Urates GGT
Ammonia	Increases by 100-200μg/L/cigar
Stress (anxiety)	Increased: “LAGIC” Lactate Albumin Glucose Insulin Cholesterol
Drugs	Medications affecting plasma volume can affect protein, BUN, iron, calcium Hepatotoxic drugs: increased liver function enzymes Diuretics: decreased sodium and potassium
Diurnal variation	"CA3PI2TG” Cortisol ACTH ACP Aldosterone Prolactin Iron Insulin Thyroxine GH