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Flashcards in Cytology Deck (27)
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Define cytology

The medical and scientific study of cells


What are the benefits of cytological analysis?

Relatively inexpensive

Identification inflammatory cells

Can be quick and easy

Identification of stages of reproduction

Identification of pathogenic cells

Identification of neoplastic cells


Give examples of cytology samples

Bone marrow

Synovial fluid - joint tap

Cerebral spinal fluid - LP

Neoplasia - FNA


How do we obtain a sample?

Fluid aspiration


Fine needle aspiration

Impression smear

Fine needle - non aspiration



CSF cells degrade rapidly. In what time scale from sampling should they be analysed?

30-60 minutes


When might an FNA be used?


Inflammatory mas


Lymph node


What are the advantages of FNA?

Quick and easy

Cheaper than surgical biopsy but less diagnostic

Minimal trauma to patient

Can be performed on conscious patient, but sedation may be required

Can be done by RVN


What gauge needle should be used for an FNA?

Less than 20g


How quickly should the sample be analysed?

Within 5-10 minutes to prevent degradation of sample


Describe the aspiration technique

Performed using a needle and syringe, with the syringe used to aspirate the cells into the needle shaft of fluid into the syringe

Can increase the risk of bleeding and cell damage, due to negative pressure

Commonly used for very firm and fluid filled masses


Describe the non-aspiration technique

A needle is used with NO SYRINGE attached

Used for sampling of very vascular masses - avoids blood contamination

Useful when sampling a precise location i.e. a small mass, thyroid gland

A core biopsy of the sample if effectively obtained, therefore, cellular structure is better maintained when compared to the FNA technique

Patients can be less apprehensive during sampling as equipment is minimal, not visualised and tissue damage is also reduced


Describe sample preparation for a smear

Sample should be rapidly transferred from the needle to a slide glass

Delay can lead to clotting within the needle shaft, trapped the sample in the shaft

Rest the needle onto the labelled slide and depress the plunger briskly, resulting in a droplet on the slide


Describe smear preparation

Squash method

Blood smear technique (feathered edge)

Line concentration technique


Touch prep

Whichever used, must produce a mono-layer of cells to allow slide to be appropriately examined


Describe the squash method

Commonly most preferred as simplest to do

Excellent for semisolid materials and small volume samples

Sample is place onto microscope slide and second slide is used to transfer the sample and spread it across a second slide

Downwards pressure should be avoided


Describe the blood smear technique

Example same technique as used for blood smear, but often slower

Can result in cell damage


Describe the line concentration technique

Excellent for semisolid materials and small volume sample

Used for samples with suspected low cellularity i.e. fluid washes

Same technique as blood smear, but spreader slide is lifted from the sample slide when approx 2/3rds along the slide

The end of line formed by using this technique will contain a concentrated quantity of cells

Can cause damage and lysis of cells due to shearing action of the slide


Describe the star method

Aspiration needle is used to drag the material into radiating streaks from the central droplet

Minimally traumatic, but is relatively ineffective method of spreading the sample thinly

Often too thick for examination


Describe the twisting technique

Second slide is applied to the surface of the droplets, slides are twisted 90 degrees counter to each other before being lifted off

Slides stick together which can cause cell damage and a smear that is too thick to assess


Describe touch preparation/impression smear

Made from crusted or ulcerated skin lesions, bone marrow

Crusts should be removed and the area of interest blotted with a tissue

This area can be moistened with a sterile cotton bud soaked in 0.9% saline (from a drip bag) or squeezed to encourage natural exudate formation

Clean microscope slide is then firmly pressed onto the lesion and sample obtained

Bone marrow can be rolled between two slide to obtain a smear


Describe sample examination

Sample should be fully dried before attempting to stain (10-20 minutes)

Stain using 'diff quick' - do not stain if sending to external laboratory

Examine under the microscope using the power x10, high power x40 then oil immersion x100

Examine the presence of white blood cells, abnormal cell morphology, malignant cells


What are the advantages of vaginal cytology?


Quick and easy

Minimally invasive and traumatic for the patient

Provides useful information to highlight timings for progesterone blood testing

Slides can be read in house if trained staff


What are the disadvantages of vaginal cytology?

Incorrect sampling can result in erroneous results

Training required to read slides correctly

Regular visits to the vets may be required

Positive result requires confirmation with progesterone blood test


Describe sampling technique for vaginal cytology

Ensure patient is suitable restrained on a table

Lips of vulva should be separated with gloved fingers and sterile cotton tip passed into dorsal aspect of the vulva

Advance the tip cranio-dorsally, towardsthe vertebral column and into the vagina. Tip should be moved into the vagina past the vestibule

Gently rotate the cotton tip within the vagina and withdraw


What are the different cell types?

Basal - Smallest and have large nucleus
Superficial/squamous cells


Describe parabasal cells

Non-cornified cell - indicate anoestrus, early pro-oestrus and diooestrus

Not present in oestrus


Describe intermediate cells

Non-cornified cells that differ in size with a prominent nucleus. 2-3 times the size of a normal basal cell

Present at all stages of oestrus cycle apart from during oestrus


Describe superficial cells

Cornified cells - very large, flat, polygonal cells with an absent or small and faint nucleus

Not commonly seen during an or dioestrus an increase in prevalance during pro-oestrus

Large numbers indicate oestrus i.e. bitch is ready for mating