Sample Submission fo Diagnostic testing

For all submissions what should be included at minimum

Patient name, age, species/breed, gender, type of sample, test requested

For all submissions what other information should be included

significant clinical findings, length of clinical signs, disease in other animals in household

What information should be included on the label

Patient name

Date collected

Type of sample

Necropsy submission should include

Complete history, including TOD

if private cremation

system(s) of interest

if you need fresh tissues

if you want any ancillary testing

Signature

What should you not do for a necropsy submission

freeze

Anatomic pathology biopsy should be

submitted in formalin

Histopathology samples

should be placed in a fixative immediately after collection and prior to submission

Fixation

Provides a snapshot in time of cellular events

Critical for maintaining tissue architecture

Stops autolysis and bacterial overgrowth which inhibit histological examination

10% formalin is preferred and is readily available pre-made (often already aliquoted  into specimen containers)

Alcohol can be used in a pinch but is NOT recommended

Must fix at least 24 hours before processing in the laboratory

Histopathology containers

should be firm plastic bottles with a wide opening and tight screw-top lids

Histopathology tissue size

1 cm or less in any ONE dimension

Why does histopathology tissues need to be a certain size?

formalin only penetrates 0.5cm into tissue

What ratio of fixative is used for histopathology

10 parts formalin to 1 part tissue

Is this appropriate for histopathology testing?

Yes

Is this appropriate for histopathology testing?

No

Tips for Histopathology

Do not grab the tissue with forceps as it causes crush artefact

Place the formalin container in a separate plastic sealable bag/additional container with absorbable material in case it leaks

Make sure submission form is COMPLETELY filled out and place this in a separate plastic sealable bag

What type of artefact does this image show?

Crush - smearing of cells inhibits identification

What should you do if you want to submit a large tissue specimen?

“bread-loaf” the specimen to allow formalin to penetrate as much of the tissue as possible

fix in an appropriate volume of formalin at your practice

you may need to replace with fresh formalin after 24 hrs, particularly with bloody tissue as the blood will bind up all the formalin

then send to lab in a smaller volume of formalin AFTER tissue is adequately fixed

What should you do if you want to submit a small tissue specimen?

Use screened cassette or cassette pads

do not just place in formalin jar

From Tissue to Slide: Step 1

Once fixed, tissues are trimmed and placed into cassettes

From Tissue to Slide: Trimmed and in cassettes

placed in an overnight processor that replaces the water with paraffin

From Tissue to Slide: In overnight processor

Tissues are embedded in fresh wax in a mold and are cooled

From Tissue to Slide: Cooled Mold

blocked are then placed in a microtome and very thin slices are made

From Tissue to Slide: Slices Made

Paced on glass slides and stained

What does this image show?

An unfixed sampled sent by practitioner

What does this image show

Fixed specimens - unfortunately the center will not be fixed

What does this image show?

sample is too large and the center is raw and unfixed

What does this image show?

Sample in narrow necked bottle

Specimens expand when fixed and cannot be taken back out

Bacteriology or Virology sample submission

tissue preferred over swabs

in sealable plastic container

overnight ship on ice

can be affected by autolysis and PM overgrowth

Bacteriology or Virology sample size

1 cm cube fresh tissue

Bacteriology or Virology swabs

make sure to use appropriate tube for test

Intestinal Bacteriology Sample requirements

Section and tie off 2-3 in apart

cut on either side of ties

submit on ice overnight

Toxicology sample submission size

minimum 50g tissue

if liquid at least 5 mls

Toxicology sample submission

place in whirl-pack or sealable plastic bag

if liquid in sealable plastic container or blood tube with no additive

tissue needed depends on test desired, call first

Parasitology sample size

100g feces