Clin Path Cytology samples and handling

What methods can you get a cytology sample from a solid mass?

Swab, Scrape, Imprint, FNA.

When are swabs used?

Only when imprints, scrapings, and aspirates cannot be done. Fistulous tracts, vaginal collections, ears.

Swab procedure

Moisten sterile cotton swab with sterile isotonic fluid, (helps minimize cell damage), Collect sample, gently roll swab along flat surface of a clean slide.

Why wouldn’t we rub a swab sample on the slide?

To avoid cell damage.

What are the two times it is ok to heat a slide.

With ear cytologies to help dissolve excess wax, and with Gram staining.

Scrapings made be made from tissues collected during when?

Necropsy, surgery, from external lesions on an animal.

Advantages of skin scrapings

Collection of many cells from a firm lesions

Disadvantages of skin scrapings

More difficult to collect, only collects superficial cells, may reflect only a secondary bacterial infection or inflammation but hinders diagnosis of neoplasia.

How to perform a skin scraping.

Localize lesion and hold scalpel blade perpendicular to the cleaned and blotted lesion. Pull the blade cross the lesion several times. Transfer collected material to a clean slide.

Impression smears may be prepared from?

External lesions, tissue removed during surgery and necropsy.

Advantages of imprints

Easy to collect and require minimal restraint.

Disadvantages of Imprints.

Few cells collected, large amount of contamination, may only reflect a secondary bacterial infection or inflammation. Hinders neoplasia diagnosis.

Tzanch preparation imprints steps

Used for external lesions, requires at least 5 slides. imprint before the lesion is cleaned. Then clean the lesion with saline and then imprint again. Debride the lesion and imprint a third time. If a scab is present imprint underside of scab #4. Impring the exposed tissue is the 5th.

Tzanch imprint preparation

Used for external lesions. Requires lesions.

Where are FNA’s taken from?

Masses, lymph nodes, nodular lesions, internal organs. Avoids superficial contamination from cutaneous lesions.

Preparation of FNA sites.

Surgical prep if microbiologic testing and collecting from a body cavity. Otherwise an alcohol prep like if doing venous puncture.

What size needle and syringe for FN biopsies.

22-25 gauge needles. The softer the tissue, the smaller the needle and the syringe.

Aspiration procedure

Holding mass, introduce needle into center of mass. Draw back the plunger until about ¾ volume. Then redirect the needle to collect sample regions. Remove needle after letting go of negative pressure. Remove needle from syringe, and draw air into the syringe, and put the needle back on. Then expel the needle contents onto the slide. Several preparations should be made if possible.

Non-aspirate procedure

Hold mass firmly, Can leave the syringe but not going to aspirate. Needle is moved rapidly back and forth 5-6 times along the same tract. It is collected by shearing and capillary action. Rapidly expel the material on the slide with the syringe.

Different tissues from surgery that get biopsied

Kidney, liver, lung, lymph node, prostate, skin, spleen, thyroid, masses.

Different biopsies

Wedge, punch, and endoscope-guided.

Wedge biopsy

Piece of tissue obtained with a scalpel. (cut off basically).

Advantages of Wedge biopsy

A large variably sized specimen, either a portion of the entire lesion. Trimmed along its axis to shows the abnormal, transition, and normal tissue zones.

Punch biopsy.

Easy and speedy procedure. 3, 4, 6, and 8mm disposable skin biopsy punches. A local anesthetic is often used. Rotate in one direction until the punch blade has sectioned the tissue. Fix in 10% formalin.

Endoscopic Biopsy.

Specimen collected by endoscopy using a flexible biopsy instrument. Specimen then blotted gently on a paper towel and placed on a small piece of tongue depressor to create a splint. Then after it is dried it is placed in fixative.

What is a centesis

Introduction of a needle into a body cavity to collect fluid. Abdominocentesis, Thoracocentesis, Cystocentesis, Arthrocentesis. Aseptic prep, 22 gauge needle, 60ml syringe.

For a Centesis what does the ease of collection depend on?

The volume of fluid present, the pressure within the cavity, the operator, cooperation of animal.

What do you record after collecting a centesis?

The total volume, and the gross characteristics of the fluids.

What is the color and turbidity influenced by?

Protein concentration, cell types, and numbers.

Transtracheal/Bronchial Wash.

Passage of catheter through an endotracheal tube in an anesthetized patient usually through the skin or trachea.

Advantages to Transtracheal route of wash and collection

May assist with diagnosis of pulmonary disease. and minimizes the pharyngeal contamination of the specimen.

Percutaneous technique. of going into the trachea.

18-20 gauge needle. Clip the hair and prepare aseptically. Lidocaine is used as a local anesthetic. Needle inserted into the trachea through cricothyroid membrane and catheter is advanced into the lumen of the trachea. Sterile saline is infused through the catheter. When the animal coughs, pull back to collect the fluid and then process the samples immediately.

Endotracheal Wash

Orotracheal Wash. Similar to percutaneous technique except the animal is anesthetized and sample collected through sterile endotracheal tube. The animal will not cough so the sample must be withdrawn as soon as the fluid is injected.

Concentration techniques.

Used when a smear is to be fluid with a cell count of less than 500ul. Low speed centrifugation, gravitational sedimentation, cytocentrifugation.