Review of Laboratory
Procedures
Basic Laboratory Rules And
Equipment
This is an FYI presentation and will
not be covered in class. However, if
you have any questions please let me
know. Thx
Basic Laboratory Rules
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No smoking, eating, or drinking
No applying cosmetics
No pipetting by mouth
All work should be done on absorbent paper
Do not let glassware accumulate
All radiation labels should be defaced prior
to discarding in regular trash
Reagents should be stored in original
container
Lab Rules Continued
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Wash hands before leaving work area
Do not lay pencils, pens, or papers on work
area
No loafing in work area
Do not give patients their results
Do not talk about patients outside of work
area
Know decontamination rules
Lab Rules Continued
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Log arrival and exit of all kits
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On Arrival
Log date received
 Company it came from
 Name of kit
 Lot number
 Expiration Date
 Quantity of vials/activity
 Whether damaged or not On Arrival
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On Exit
If given to patient make list of who, what, and when
 Dispose of containers in proper receptacles
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Laboratory Equipment
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Syringes
Balances
Flasks
Pipettes
Test Tubes
Centrifuges
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Water bath
Ice bath
Refrigerator
Rotators
Shakers
Balances
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Top Loading
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Double Pan
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Like bathroom scales
Uses counter weights
Analytical Balance
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Most accurate
Based on principle by comparing the mass of
an unknown with that of calibrated weights
Flasks
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Erlenmeyer Flasks
Beakers
Volumetric
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Calibrated to contain preparing solutions of
exact concentrations (used for blood volumes)
Types of Pipettes
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There are two types of pipettes
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Graduated
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A calibration mark decides how much liquid can be
dispensed--come in whole number denominations
Volumetric
Most accurate of glassware
 Always calibrated to measure and/or deliver exact
volumetric quantities of liquid substances
 Limited to measurement of a fixed, single volume.
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Generally, these pipettes deliver their inscribed volume by
complete drainage of the pipette from an etched mark. They are
normally used for the accurate transfer of 1.0, 2.0, 5.0, 10.0, and
25.0 ml of liquid.
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Graduated
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Volumetric
To Deliver Versus To Contain
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To Deliver (TD)
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Allows for some liquid
always remaining
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To Contain (TC)
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Desired volume is
present, but it is
impossible to get out
Calibration of Pipettes
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Pipettes are calibrated at the factory with
Mercury at 20 degrees Celsius with an
error percentage of +/- 1%
Blood versus Liquid Pipettes
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Blood Pipettes
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Thin walled
Bigger bore
Read the top of the
meniscus
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Liquid Pipettes
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Thick walled
Small bore
Read the bottom of
meniscus
Meniscus
A meniscus is where surface tension attracts
liquid, creating a bubble looking line
How To Use A Pipette
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Never pipette by mouth
Use a vacuum creator
Hold pipette close to mouth piece (top)
Dispense straight up with tip on glass
deep enough, so as not to splash
Perform quality control daily
Types of Test Tubes
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Polypropylene
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Polystyrene
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Cloudy Plastic
Clear Plastic
Glass
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Clear
Centrifuges
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Centrifuges are used as separators
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Non-refrigerated
Refrigerated
Ultra-centrifuge
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Micro-centrifuge
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Super fast--38,000 RPM
Holds only small tubes
Hematocrit-centrifuge
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Holds only glass capillaries
Centrifuges
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Centrifuges operate on centrifugal force
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Heavier objects go to the bottom due to being
thrown to the outside
Most samples require 5,000 RPM
RCF is used by determining the radius and the
speed (RPM)
RCF is measured in g, as in g-force, or gravity
Guidelines for Using Centrifuges
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Close and lock centrifuge before starting
Always balance tubes
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Do not open while centrifuge is going
Do not use brake unless extremely necessary
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Balance with like substance if possible, resulting in the
same mass and center of gravity in each tube
Most damage of sample is caused by either an improper
balance, too high RPM, or braking
Do not place hands in centrifuge while it is going
Collection Tubes
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The type of tube that a blood sample is
drawn in determines whether the straw
colored fluid of a settled centrifuge sample
is serum or plasma.
Serum contains no clotting factor, while
plasma contains an anti-coagulant.
Types of Collection Tubes
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Red Stopper
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Yellow Stopper
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Sodium Heparin
Purple Stopper
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Acid Citrate Dextrose
Green Stopper
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No anti-coagulant
EDTA (Ethyline diamine tetric anticoagulant)
Grey Stopper
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Sodium Fluoride
Problems With A Blood Sample
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Hemolized
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Lypholized
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Damaged RBC’s are mixed in the serum plasma
resulting in a pink color
White milky serum/plasma due to eating a fatty
meal before drawing blood
Icteric
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Bile in the blood due to liver disease; serum/plasma
turns a yellow green color
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Dilution
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A solution that contains a relatively small amount of
solute
Solvent
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Making a weaker solution from a stronger one
Dilute solution
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Dilution Terminology
A substance in which another substance, called
solute is dissolved
Solute
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Solution component present in smaller amount than
solvent
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Dilution Factor
This is the extent to which you have diluted your
selected amount of stock solution and is given by the
formulas:
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V2/V1 or C1/C2
In other words, we can either see how many times the
volume has increased after the dilution which is
100mL/50mL = dilution factor of 2 in the previous
problem. You could also say the concentration halved,
so 0.100uCi/0.050uCi = dilution factor of 2.
Either way results in the same answer, but keep in
mind a dilution factor always needs to be greater than
1. If your final answer is less than 1, you divided the
wrong way which implies you concentrated instead of
diluted. This is a way to check to make sure you did
the math correctly.
Why Dilute?
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If the concentration of the solution that
needs to be analyzed is too great to be
accurately determined
Dilutions are usually referred to as a
ratio of 1 to 10--one unit of original
solution diluted to a final volume of 10
units
1 original + 9 dilutant = 10 units
Dilution Principle
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Dilution principle can be expressed
mathematically:
Q=VxC
Where:
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Q = Quantity of Tracer
V = Diluting Volume
C = Tracer concentration in fluid
Dilution Formula
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Original Concentration x Dilution ratio = Final
concentration
Original Concentration of solution
Desired Concentration of solution = Dilution
Ratio*
*Dilution ratio is also known as dilution factor
Example Dilutions
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Final concentration of an original solution of
500 mg/ml diluted to 1:25 solution
500 mg/ml x 1/25 = 20 mg/ml
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Have a 8mg/ml solution and want a 2 mg/ml
solution
8 mg/ml
2 mg/ml = 4 units or a 1:4 ratio
1 part original 3 parts solvent
Series Dilution
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If more than one dilution is done within a given
solution, the concentration of the solution is
achieved by multiplying the original
concentration by the series of dilutions.
Example
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1000 mg/ml diluted to 1:10 and then diluted 1:100
1000mg/ml x 1/10 x 1/100 = 1 mg/ml
Conclusion
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There is a variety of lab equipment that must
have quality control performed on it daily.
Safety is a concern when dealing with
laboratory equipment, as well as body fluids.
Dilutions may be necessary if the
concentration is too high to be measured by
available methods.
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