MT- Chapter 1 : Specimen Handling and Identification / Chapter 2 : Methods of Fresh Tissue Examination Flashcards
Frequently used by clinical laboratories
Bar codes / Log books
Log books should include :
The time it was received The date it was received Full name of the patient Sample submitted Type of specimen Accessioning code
The specimen container label and the accompanying request form should include
Patient’s name,
Age or birth date,
A medical record number.
The request form should have :
provisional diagnosis and brief clinical details.
What is the purpose of Workup sheets?
It is used as a guide for the Pathologist and to check on what specific concern of that doctor
It is a list that has been done during excision and incision of the sample
Workup sheets
It includes Infos about what is the problem during the take out of specimen in the human body
Workup sheets
Incorrect identification of any specimen results in the :
wrong diagnoses and incorrect treatment.
Major components in grossing a specimen:
o Reliable and rapid transfer of the specimen from surgery to pathology
o Accurate identification of the specimen
o Description of additional specimens received from the same patient
o Gross description of the specimen’s normal and abnormal features
o Recording the sites from which blocks of tissue are taken
o Recording markers that help with the correct orientation
o Identifying special studies requested and/or needed.
Specimen from Dermatology
1) Core Biopsies
2) Shave Biopsies of Skin
3) Excisional Biopsy
4) Re – excision Specimens
5) Non – skin Specimen (Excisional biopsies)
Larger core biopsies
- (4mm)
- should be bisected eccentrically
and embedded with cut surfaces down.
Small core biopsies
- (2mm)
- should be embedded totally
without cutting it.
Depending upon the size of the biopsy, it may be bisected,
trisected, or cut into sections.
Shave Biopsies of Skin
Most specimens of skin or other epithelial surfaces should be
cut
Shave Biopsies of Skin
In Shave Biopsies of Skin, all aliquots are embedded on
edge
o Care should be taken with any pigmented lesions of the skin.
Shave Biopsies of Skin
Method of choice for surgical removal of melanomas but may
be sometimes removed by shaving.
Excisional Biopsy
What is the purpose of examining biopsies of skin?
Biopsies of the skin are examined to ensure that the lesion has been completely removed and the original clinician’s diagnosis was correct.
In excisional biopsy, it can oriented using:
sutures or dyes
Original site of a lesion may need to be re-excised if:
o The margins are invaded by tumor
o Too close to the tumor: melanoma / basal cell carcinoma
Operative specimens
tumors,
unidentifiable inflammatory masses,
tissues
Operative specimens are removed prior to:
transplantation,
traumatic,
congenital malformations,
or cosmetic surgical specimens.
why all specimens must be examined carefully?
because specimens may harbor unsuspected malignant tumors.
Important determinants of neoplastic specimens:
o Overall size of the tumor
o Depth of invasion into or through the tissue walls
o Involvement of margins and lymph nodes
What is the purpose of formalin?
To preserve the integrity of the specimen
specimens should be transferred to a fixative within:
within 1 hour
Teasing or Dissociation
A process whereby a selected tissue specimen is immersed in a watch glass containing isotonic salt solution, carefully dissected or separated, and examined under the microscope
Other name for Squash Preparation
Crushing
Smear Preparation
The process of examining sections or sediments, whereby cellular materials are spread lightly over a slide by a wire loop or applicator, or by making an apposition smear with another slide.
Smear Preparation includes:
a) Streaking
b) Spreading
c) Pull – apart
d) Touch Preparation (Impression smear)
Streaking
with an applicator stick or platinum loop, the material is rapidly and gently applied in a direct or zigzag line throughout the slide, attempting to obtain a relatively uniform distribution of secretion.
Spreading
a selected portion of the material is transferred
to a clean slide and gently spread into a moderately thick film by teasing the mucous strands apart with an applicator stick
Advantage of Spreading
This method is a little more tedious but with the advantage of maintaining cellular interrelationships of the materials to be examined.
Spreading is recommended for:
Recommended for smears preparations of fresh sputum
and bronchial aspirates and for thick mucoid secretions.
Pull – apart
done by placing a drop of secretion or sediment upon one slide and facing it to another clean slide.
The material disperses evenly over the surface of the two slides.
Slight movement of the two slides in opposite directions may be necessary to initiate the flow of materials.
The two slides are then pulled apart with a single uninterrupted motion, and the specimen is placed under the microscope for immediate examination or applied with vital stains.
Touch Preparation (Impression smear)
a special method of smear preparation whereby the surface of a freshly cut piece of tissue is brought into contact and pressed onto the surface of a clean glass slide, allowing the cells to be transferred directly to the slide for examination.
Advantage of Touch Preparation :
Cells may be examined without destroying their actual intercellular relationship.
normally utilized when a rapid diagnosis of the tissue in question is required.
Frozen Section
Frozen Section is recommended when:
recommended when lipids and nervous tissue
elements are to be demonstrated
Applications of Frozen Section:
- Rapid pathologic diagnosis during surgery
- Diagnostic and research enzyme histochemistry
- Diagnostic and research demonstration of soluble
substances such as lipids and carbohydrates - Immunofluorescent and immunohistochemical staining
- Some specialized silver stains particularly in
neuropathology
Pull-Apart is useful for:
Useful for preparing smears of thick secretions such as serous fluid, concentrated sputum, enzymatic lavage samples from GIT, and blood smear.
Liquid Nitrogen is generally used in:
histochemistry and during operative procedures
Most rapid of the commonly available freezing agents
Liquid Nitrogen
Disadvantage of Liquid Nitrogen:
Soft tissue is liable to crack due to rapid expansion
of the ice within the tissue – producing ice crystals or freeze artifacts
Problem of using Liquid Nitrogen:
The use of liquid nitrogen can cause a vapor phase to form around the tissue acting as an insulator that causes uneven cooling of tissue (particularly in muscle biopsies) and makingdiagnostic interpretation difficult.
