Pipetting Techniques Flashcards
for the quantitative transfer of reagents and the preparations of serial dilutions of specimens
such as serum.
Pipettes
Can make the specimen unacceptable
Lipemia, hemolysis, and bacterial contamination
pressure of excess bilirubin in the blood system, turbid serum
Icteric
Blood specimens should be collected ____ to avoid chyle
Before a meal
a milky bodily fluid consisting of lymph and emulsified fats, or free acids
Chyle
dark to very dark yellow, brownish like sample
Icteric Sample
Expect patients with steric sample to have a very high ___ or ____
bilirubin or ALT/SGPT
ALT normal value parameter for liver diseases
55 lU/L
Fatty liver disease
> 55 lU/L
• damaged /scarred liver
> 200 |U/L
liver cirrhosis
> 1000 IU / L
liver cirrhosis reversible stage
Stage 1-3
liver cirrhosis irreversible stage
stage 4
Turbid to milky consistency of the sera
Lipemic Sample
Expect patients with Lipemic Sample to have a very high ___ and ____
Cholesterol and Triglycerides
Calculation for total cholesterol
HDL + LDL + Triglycerides / 5
Red sample (Destruction of red blood cells)
Hemolyzed Sample
hemolyzed sample means elevated level of ___
Elevated levels of Potassium
Potassium Nv
NV: 3.5 - 5.0 mmol / L
Number of samples per hour for manual pipetting
5-10 samples per hour
the curvature in the top surface of a liquid
Meniscus
The greatest potential hazard is when ___ pipetting is done instead of mechanical suction.
mouth pipetting
offers a way for labs to incrementally scale up
production and increase reproducibility
Semi-Automatic Pipettes
Number of samples per hour for Semi-Automatic Pipettes
11-100 samples per hour
most valuable in high-throughput applications
that benefit from completely removing human
movements
Automation
can process hundreds of samples at a time and
follow highly complex methods without deviation
Automation
can cause problems with the. measurement and delivery of samples and solutions.
Bubbles and viscous solutions
Bubbles =
wrong procedure handling
Complement can be inactivated by heating to ___ C for ___minutes, or after ___hours, reinactivared by heating for __ minutes.
heating to 56 C for 30 minutes, or after 4 hours, reinactivared by heating for 10 minutes.
disposable plastic pipes used to transfer small
volumes of liquids
Transfer pipette
“To deliver” (TD) types that have the bulb closer to the center and accurately deliver a fixed volume of aqueous solution
Volumetric pipette
TD types that have the bulb closer to the delivery tip
because they deliver viscous fluids.
Ostwald Folin pipette
These pipettes deliver an accurate volume by being “blown out” using a pipetting bulb.
Ostwald Folin pipette
a pipette with its volume, in increments, marked along the tube.
Graduated pipette
It is used to accurately measure and transfer a volume of liquid from one container to another.
Graduated pipette
The orifice, or tip opening, is larger than in other pipettes.
Serological pipette
The rate of fall of liquid is much too fast for great accuracy or precision.
Serological pipette
Serological pipette is calibrated to the tip and must
be ___ to deliver the entire volume.
Blown out
The need to blow out is indicated by the ___ at the top of the pipette
etched rings
calibrated between marks
cannot be “blown out”
mohr pipette
allow rapid repetitive measurement and delivery
of predetermined volumes of reagents and
specimens
Micropipette
piston-operated devices that allow repeated,
accurate, reproducible delivery of specimens, reagents, and other liquids requiring measurement in small amounts
Micropipette
Difference between mohr and serological pipette
mohr- graduated between two marks
Serological - grade mark down to the tip
Common Pipetting Errors
- Loose pipette tip
- Tilting the pipettor
- Plunger quick release (will cause air bubbles)
- Second stop draw
