intro to histopath techniques Flashcards
what is histopathologic techniques
Provide the basic concepts about the principles
and technicalities involved in histopathologic
procedures
Provide skills in tissue preparation from fresh
to properly mounted specimen.
histopathologic techniques
The art and science performed by the
histotechnologist to produce a tissue section of
good quality.
histotechnology
Processing of Tissue
studying tissues
whether normal or abnormal is by examination of their sections & smears
which have been permanently preserved, stained & mounted on glass slides with
cover slips for permanent keeping
- Effective means of studying tissues whether normal or abnormal
- Examination of sections & smears which have been permanently preserved
- Stained & mounted on glass slides with cover slips for permanent keeping.
why examine histopathologic specimen
Determine if the sample is benign or malignant
procedures adoptedfor the preparation of material for such studies
Histologic or Histopathologic technique
fresh tissue
- protoplasmic activities
- mitosis
- phagocytosis
- pinocytosis
what is preserved tissue?
- observe in lifelike manner
- through the action of fixative solution
methods of fresh tissue examination
- teasing or dissociation
- squash preparation
- smear preparation
- frozen section
advantages of fresh tissue
- examined in the living state thereby allowing protoplasmic activities such as mitosis, motion, phagocytosis, and pinocytosis to be observed
disadvantage of fresh tissue
its use has been limited
most common procedure of fresh tissue examination
frozen section
A process whereby a selected tissue specimen is immersed in a watch glass containing isotonic salt solution,
teasing or dissociation
fresh tissue is unstained by
phase contrast or bright field microscopy
fresh tissue is stained with
differential dyes (methylene blue)
hypertonic solution
cell will shrink
hypotonic solution
cell will swell
A process whereby small pieces of tissue not more than 1 mm in diameter are placed in a microscopic slide and forcibly compressed with another slide or
with a cover glass
squash preparation or crushing
useful in cytologic examination
smear preparation
cellular materials are spread lightly over a slide by
means of a wire loop or applicator.
smear preparation
used for cancer diagnosis
smear preparation
With an applicator stick or platinum loop, the material
is rapidly and gently applied in a direct or zigzag line throughout the slide
streaking
Gently spread into a moderately thick film by teasing the mucous strands apart with an applicator stick
spreading
2 slides are then pulled apart in a single uninterrupted
motion
pull apart
Brought into contact and pressed on to the surface
of a clean glass slide
Touch Preparation (Impression Smear)
- For fresh sputum and bronchial aspirates
- For thick mucoid secretions
Spreading
Allowing the cells to be transferred directly to the
slide for examination by Phase Contrast microscopy
or stained for light microscopic study
Touch Preparation (Impression Smear)
atmospheric temperature of cold chamber
10-20C
Recommended for lipids and nervous tissue
frozen section
methods used for freezing
ü Liquid nitrogen
ü Isopentane cooled by liquid nitrogen
ü Carbon dioxide gas
ü Aerosol sprays
tissue processing in order
fixation > dehydration > clearing > section cutting > trimming > embedding > infiltration (impregnation) > staining > mounting > labeling
disadvantage of liquid nitrogen
crystallization of soft specimen ; crackening
particularly for muscle biopsies
isopentane
conventional freezing microtome gas
carbon dioxide gas
often referred to as “cut-up”
grossing
involves careful examination and description of the specimen its - appearance, - number of pieces and dimensions
grossing
the most important processes in which the pathologist arrives at a diagnosis
Gross Examination of Specimens
Criteria for rejection of gross specimen
*Discrepancies between the requisition and specimen label
* *Specimen with no labels, or mislabeled
* *Leaking specimen container
* *Absent clinical data or history - Pre Op - Operative and Post Op
* *Inappropriately identified specimen
to identify and orient the spec component
inks
for indicating laterality
nicking
represented as
* *LL – long lateral
* *SS- short superior
suture attaches
measurement of standard cassette
3.0x2.5x0.4 cm
Responsibility of a technician
vSpecimen preservation.
v Specimen labeling, logging and identification.
vPreparation of the specimen to facilitate their gross and microscopy.
vRecord keeping
inking
- resection margins
- embedding instruction
- orientation
- acetic acid
- identify the cut surfce
Two methods of preparing frozen
sections
- Cold Knife Procedure
- Cryostat procedure
Tissue blocks can be frozen by adapting a conventional freezing microtome gas supply of
carbon dioxide gas from a C02 cylinder, or by using a specially made piece of equipment
known as cryostat
Cold Knife Procedure
consists of an insulated microtome housed in an electrically driven
refrigerated chamber and maintained at temperatures near -20°C, where microtome,
knife, specimen and atmosphere are kept at the same temperature.
Cryostat Procedure
Methods used of Freezing
Liquid nitrogen
Isopentane
Carbon dioxide gas
Aerosol sprays adequate for freezing small pieces
rapidly freezing blocks of any type of tissue.
Rapid pathologic diagnosis during surgery
frozen section
Recommended for lipids and nervous tissue
frozen section
