Lecture 1 Flashcards
What is clinical chemistry?
Soluble mediators of a system; includes taking blood, centrifuge and using serum/plasma (formed elements)
How long does it take serum tube to clot?
roughly 30 minutes +/- this also effects trauma times
True or false: DT2 is one of the biggest finanical burdens in the U.S?
True, it is also common w kidney disease
What are a few things included in a Basic Metabolic Pannel? (BMP)
“Basic” “Mini”
Glucose
Albumin
Total Protein
Na, K, Chloride
BUN (blood urea nitrogen)
Creatine
CO2
What are the most common panels ordered in Chemistry?
BMP and CMP
What are a few things included in CMP?
Complete metabolic pannels include BMP plus liver function. ALT, AST, ALP and Bilirubin
True or false: Glucose and triglycerides are not affected by fasting?
False, they are affected by fasting
What are some things included in the lipid profiles (other common chemistry test)?
includes lipids like tryglycerides, cholesterols, HDL, and LDL (calculated or direct)
What are included in Pancreatic Fx? (other common chemistry test)
Amylase
Lipase
What is the Matrix?
Plasma or Serum in chemistry, Serum is the preferred specimen and is easy to obtain/repeat. Used on almost all assays
True or false: Urine is not testing in parallel with kidney function and serum levels
False, urine and the kidney are tested in parallels in chemistry
Reagent + Compound = _____?
Color changes, direct or indirect
True or false: color change rx can help determine wavelengths
True
What kind of system is the best for quantitating color change?
Closed system utilizing focused light spectra
True or false: In spectrophotometry, the photometric system uses light intensity with wavelength
false, photometric uses light intensity w/ OUT wavelength
What is Beers law? (In words)
Concentration of substance is directly proportional to amount of light absorbed or inverse to log of transmitted light
What do spectrophotometry instruments do?
measures light by solution to determine concentration of light absorbed substance in a solution
What are the components of a spectrophotometer?
light, monochromator, sample, and photo detector
true or false: frequency is proportional to wavelength
FALSE. Frequency is inversely proportional to wavelength
What is wavelength?
distance of one complete cycle and measured in nanometers
What is electromagnetic radiation?
protons of energy in waves
What is the values on the visible spectrum?
400-700 nm which is violet to red, red having the longest wave length
True or false: light sources are intense, constant, and reproducable
true
What are the most common light source in chemistry and which parts of EM spectrum do they cover?
- Tungsten (visible + IR)
- Deuterium (ultraviolet region)
True or false: you dont need to change the calibrations every time you change a light sourse
false, you need to update the calibrations when the light source is changed
What is the equation for percent transmittance?
%T = sample beam signal/blank beam signal x 100
= T/I x 100
What does the T/I x 100 variables mean in the equation for precent transmittance (%T)?
T - radiant energy transmitted
I - incident radiant energy on the sample
What kind of transmittence does water have? Milk? Heavy cream?
Water - 100% transmittence
Milk - some
Heavy cream - no light can pass through
If 70% of light is transmitted, how much is absorbed?
30% is absorbed
What is the beers law equation in chemistry and what do the variables mean?
A = E x B x C
B = length of light path through solution
C = conc. of light path through molecules
E = molar absorptivity/extinction coefficient
Photodetectors: What is the photodetector that is basic and uses incident light? Explain a few more things included with this source.
Photocells:
Typically used in the dark, uses a cathode of salinium, generates electrons/lines of silver
OK for low concentrations
true or false: Photocells are sensitive
False, they are not very sensitive
True or false: phototubes have an external source of power and are better w/ small amounts of light/ they also use a vacuum to avoid scatter
true
What does a photomultiplier use?
dynode chains, each anode has a higher voltage than the last
extreme sensitivity to low light and/duration
Amps are proportional to light intensity
True or false: photomultiplier is 300X more sensitive than phototube
False: 200X more sensitive
What are diodes?
anodes with succ. higher voltages
True or false: This is the pathway of photodetectors in order from top to bottom:
Light
Amps
Electrons
volts
absorbance
False:
Light
electrons
amps
volts
absorbance
What does a dift filter do?
gets rid of interfering substances
What are common checkers of wavelength accuracy?
Didymium and holmium oxide, sometimes mercury can verify
What is the stray light effect? Common causes?
any light outside the band of transmittance
Causes: scratches on optical surface, dust/oil from fingers …etc
What is linearity?
Change in concentration results in a straight line, must happen every 6 mos
What is the difference between reference range and linear range?
RR: normal for population
LR: how high or how low you can test
Describe Atomic Absorbtion
used to detect absorbance of electrons by atoms rather than molecules
Fluometry uses what and what are the advantages/disadvantages?
Uses fluorescense
Two advantages: Specificity/sensitivity
Disadvant: VERY sensitive to environment changes (pH, Temp..etc)
Describe Chemiluminecense and its positives and negatives
chemilum.. is the emission of light by molecules through chemical reactions
(no excitation or monochromes)
+ subpico detection
- impurities that degrade sensitivityspecificity
Describe Turbidemetry
made w/ spectrophotometer to determine concentration of matter in a substance that can pass though 180 degrees from incident light (SAMPLE HANDLING CRITICAL)
Describe Nephelometry
90 degree angle from incidence light minimizes errors from solution and increases sensitivity