Lab 2- Blood Films/ Differential Cell Counts/ Determining Blood Groups By Haemagglutination Flashcards
(36 cards)
What was the goal for Blood Films and Differential Cell Counts experiment?
This practical gave us direct experience working with blood for common techniques of preparing a blood slide and preparing plasma for analysis.
- Working with blood risk assessment
- Preparation of a blood film and differential cell count
- Centrifugation of blood and separation of components
What diseases might you be exposed to when working with blood?
HIV, Hepatitis B (HBV), Hepatitis C (HBC) and other diseases found in the blood.
How can you reduce the risk to yourself and your colleagues?
Disposal of needles in appropriate sharp disposal and safer techniques e.g. not recapping needle by hand. Exposures to the eyes, nose, mouth and skin can be prevented by using PPE equipment. Being focussed while handling medicine and not being distracted.
What is Harleco’s Diff-Quik Stain Set?
Has advantages over the routine Wright-Giemsa staining technique. It reduces the 4-minute process into a much shorter operation of 15 seconds and allows for selective increased eosinophilic or basophilic staining depending upon the time the smear is left in the staining solutions.
List 3 common reasons for a poor blood smear
- Spreader slide pushed across the slide in a jerky manner
- Drop of blood too large or too small
- Failure to keep the entire edge of the spreader slide against the slide making the smear.
How can you adjust the thickness of the smear?
- Angle of the spreader slide angle
- Size of blood droplet
- Speed of spreading
Why is proper specimen labelling so important?
- Has a positive impact on patient care
- Protects specimen quality
- Eliminates risk of exposure to the healthcare worker
- Complies with all accreditation standards
The Diff Quik stain is a commercial variant of the Wright stain. Describe the two dye components.
• Diff-Quik solution I (eosinophilic)
o Xanthene dye (Eosin Y)
o pH buffer
• Diff-Quik solution II (basophilic)
o Thiazine dye, methylene blue and azure A
o pH buffer
Why were we looking at the blood smears?
A stained smear is examined in order to determine the percentage of each type of leucocyte present and assess the erythrocyte and platelet morphology. Increases in any of the normal leucocyte types or the presence of immature leucocytes or erythrocytes in peripheral blood are important diagnostically in a wide variety of inflammatory disorders and leukaemia.
Erythrocyte abnormalities are usually a sign of..
Various anaemias
Platelet size irregularities are suggestive of..
Thrombocyte disorders
Incorrectly prepared films may show…
May have too many large cells at the film edges, leaving relatively smaller cells, such as lymphocytes, in the center and results in inaccurate manual differential counts.
How did we estimate WBC count/μL?
Divide the total number by 10 to establish the mean number of leucocytes per field. Multiply the mean by 3000 to determine the estimated WBC count/μL.
What do the RBC look like?
Reddish, pink anuclear cells with one-third central pallor
What do eosinophils look like?
Bi-segmented nucleus and bright red/orange cytoplasmic granules
What do lymphocytes look like?
Round with dark purple nuclei with varying shades of blue cytoplasm
What do basophils look like?
Rare cells (<1%) with dark blue purple granules that overlie the nucleus
What do the neutrophils look like?
Dark purple segmented (3-4 segments) nuclei with azurophilic pink granules in the cytoplasm
What do the monocytes look like?
Largest cell with lighter purple horseshoe-shaped nucleus with a grey-blue cytoplasm.
What do platelets look like?
Small anuclear particles between the RBC that have pink granules
What forces do antibody and antigen interact with?
Interact via reversible, non-covalent interactions that are mediated by hydrogen bonds, ionic bonds, electrostatic forces and Van der Waals interactions.
The strength of the Ab-Ag reaction is called the ___________ and is a quantitative measure of binding strength. It is the combined strength of the non-covalent bond and varies broadly amongst immunoglobulins.
AFFINITY
________ is the collective affinity of multiple binding sites on an Ab molecule. It represents the true strength of Ag-Ab interaction in biological system as interaction at one site increases possibility of interaction at second site. Therefore, _____ avidity can compensate for ______ affinity.
AVIDITY is the collective affinity of multiple binding sites on an Ab molecule. It represents the true strength of Ag-Ab interaction in biological system as interaction at one site increases possibility of interaction at second site. Therefore, HIGH avidity can compensate for LOW affinity.
Explain in a few sentences how the valency of antibodies affects avidity
The greater an immunoglobulin’s valency (number of antigen binding sites), the greater the amount of antigen it can bind. Similarly, antigens can demonstrate multivalency because they can bind to more than one antibody. Multimeric interactions between an antibody and an antigen help their stabilization.
