Cytology Flashcards
What are fine needle (aspirate) biopsy (FNBs) used for?
To obtain small samples of cells from inside organs or masses.
How can a FNB be performed?
‘Blind’
Using ultrasound (able to accurately sample target and visualise surrounding structure)
What can FNB cause and what does this mean when sampling animals?
May cause haemorrhage.
Inappropriate for sampling in an animal with a coagulation defect or in highly vascular masses
What tissues iS a FNB appropriate for?
Tissues where cells exfoliate easily or those which are highly vascular and hence blood contamination of the sample is a likely problem. E.g. lymph nodes, the liver and spleen
What tissues is a fine needle aspirate biopsy appropriate for?
Highly structures tissues which don’t exfoliate well e.g. muscle and spindle cell masses
What should you do before performing FNBs?
Prepare the skin over the mass aseptically
What size needle should be used for FNBs and why is this chosen?
22G needle.
21G are wider and more likely to cause haemorrhage.
23G are narrower so likely to yield fewer cells.
What should you remember when collecting the sample in FNBs once the needle has broken the skin?
Don’t remove the needle from the skin.
Slightly withdraw and redirect it several times within the tissue to sample several different areas.
What should you do before connecting the needle to the syringe?
Draw up 5ml of air in a 5ml syringe
How do you get the sample from the needle onto the slide?
Hold the needle, bevel down, just above one of the microscope slides. Vigorously expel the air.
Once the sample is on the slide, what is the next step in FNBs?
Take another clean microscope slide and lay it on top of the one with the sample on it. Slide them over one another in one direction to smear the sample over both slides.
What is the difference between the technique used for FNB and FNB aspirate?
Syringe connected to needle in FNaB.
In FNB aspirate, you should insert then needle in the sample a then draw back the syringe (2/3ml). This negative pressure is maintained while redirecting the needle. Release the negative pressure while the needle is still in the sample.
What should you remember once you remove the needle from the sample in FNaB?
Remove the needle from the syringe.
Draw air into the syringe.
Reattach the needle back onto the slide.
Expel the sample onto the slide.
What is an impression smear useful for?
Ulcerated masses, pastures or to take from the cut surface of a mass to examine while you wait for histopathological diagnosis.
What kind of tissues is an impression smear used on?
Highly exfoliative tissues (e.g. lymph nodes) rather than ones with rigid architecture e.g. tumours of fibrous tissues.
What is the method used when performing an impression smear?
Gently blot the surface to remove blood contamination.
Press the cut surface of the sample on to the face of a clean slide.
Allow to air-dry
What is the tape strip method often used for?
Skin cytology and for in-house examination.
Useful for identification of surface infectious agents.
What should you remember before taking a sample using a tape strip?
Do not aseptically prepare the area as its the surface cytology we are looking at
What length should the tape be?
A little longer than the microscope slide
What is a vital thing to remember when performing a tape strip sample?
Do not touch the underside of the tape
How many times should you press the tape onto the area of interest?
Several times to gather cells on the tape surface
What should you do once you have taken the sample and it is now on the tape?
Attach the end of the tape to the non-frosted end of a clean slide
When staining the sample, what is it vital to remember?
Do not use fixing solution A as this will melt the glue on the tape.
Use B and C the rinse with distilled water.
How do you get the sample from the tape onto the slide?
Stick the tape along the slide, blotting gently with a tissue to ensure good adherence.
