M2: Microscopic Examination (Part 3: Microscopy) Flashcards
is the most common type of microscopy performed in the urinalysis laboratory.
Bright-field microscopy
The type of microscopy used depends on what 3 factors
- specimen type
- refractive index of the object
- ability to image unstained living cells.
Identify what system the following parts of microscope belong to:
oculars, objectives (coarse & fine adjustment
knobs)
Lens system
Identify what system the following parts of microscope belong to:
light source, condenser, field diaphragm
Illumination system
Identify what system the following parts of microscope belong to:
base, body tube, and nosepiece
Body
Identify what system of the microscope:
holds the slide on place
Mechanical stage
EYEPIECE
Clinical laboratory microscopes are?
binocular
allowing the examination to be performed using both eyes to provide
more complete visualization
EYEPIECE
can be rotated to compensate for variations in vision between the operators’ eyes
diopter adjustment knob
EYEPIECE
can be adjusted horizontally to adapt to differences in interpupillary distance between operators.
oculars
EYEPIECE
Laboratory microscopes normally contain oculars capable of increasing the magnification to how many times.
10 times (10x)
EYEPIECE
T or F
The field of view varies with the field number engraved
on the eyepiece and the magnification of the objective
T
EYEPIECE
T or F
The higher the magnification, the higher the field of view
will be
F (The higher the magnification, the smaller the field of view
will be)
EYEPIECE
Formula for field of view?
Field no. ( diameter in mm) / M (magnification of objective)
- are adjusted to be near the specimen and perform
the initial magnification of the object on the mechanical
stage - image then passes to the oculars for further
resolution (ability to visualize fine details)
Objectives
2 features of objective lenses?
- Parcentered
- Parfocal
OBJECTIVES
ability to retain the central FOV ( (when the
user switches from one objective to another)
2 features of objective lenses
Parcentered
OBJECTIVES
ability of the objective to remain in focus regardless of the objective used
2 features of objective lenses
Parfocal
OBJECTIVES
is the ability of the lens to distinguish two small
objects that are a specific distance apart
Resolution
OBJECTIVES
- is best when the distance between the two objects is small
- dependent on the wavelength of light and the numerical aperture of the lens
Resolving power
OBJECTIVES
T or F
The shorter the wavelength of light, the greater the resolving power of the microscope will be.
T
OBJECTIVES
Routinely used objectives in the clinical laboratory and their magnification
10× (low power, dry), 40× (high power, dry),
and 100× (oil immersion)
OBJECTIVES
objectives used for examination of urine
sediment
10× and 40×
OBJECTIVES
The distance between the slide and the objective is controlled by the?
coarse- and fine-focusing knobs
OBJECTIVES
- Initial focusing is performed using this
- moves the mechanical stage noticeably up and down until the object comes into view
coarse knob
OBJECTIVES
sharpen the image
Fine-focusing knob
OBJECTIVES
T or F
When using a parfocal microscope, the coarse and fine knob should be used for adjustment when changing
magnifications
F ( only the fine knob should be used for adjustment when changing magnifications)
OBJECTIVES
- is the distance between the objective & the coverslip on the slide
- decreases as magnification of the objective increases
Working distance
OBJECTIVES
T or F
Working distance increases as magnification of the objective increases
F (Decreases as magnification of the objective increases)
OBJECTIVES
Identify what objective:
Magnification - 4x
Color- red
Scanner
OBJECTIVES
Identify what objective:
Magnification - 10x
Color- yellow
LPO
OBJECTIVES
Identify what objective:
Magnification - 40x
Color- Blue
HPO
OBJECTIVES
Identify what objective:
Magnification - 100x
Color- White
OIO
ILLUMINATION
light source located in the base of the microscope
Illuminator
ILLUMINATION
Equipped in light source that regulate the intensity of the light
rheostat
ILLUMINATION
may also be placed on the light source to vary the illumination and wavelengths of the emitted
light
Filters
ILLUMINATION
contained in the light source controls the diameter
of the light beam reaching the slide and is adjusted for optimal illumination
field diaphragm
ILLUMINATION
located below the stage then focuses the light on the specimen and controls the light for uniform illumination
condenser
ILLUMINATION
this specific component in the condenser controls the amount of light and the angle of light rays that pass to the specimen and lens, which affects resolution, contrast, and depth of the field of image
aperture diaphragm
ILLUMINATION
moves the condenser up and down to focus light on the object
condenser adjustment (focus) knob
ILLUMINATION
Maximum resolution is achieved by adjusting aperture diaphragm to what percent?
75% of the
numerical aperture of the objective
ILLUMINATION
T or F
The aperture diaphragm can be used to reduce light intensity because it increases resolution
F ( The aperture diaphragm should
not be used to reduce light intensity because it decreases resolution)
ILLUMINATION
What is used to reduce light but retain resolution
microscope lamp rheostat
CENTERING THE CONDENSER AND KÖHLER
ILLUMINATION
Two adjustments to the condenser that provides optimal viewing of the illuminated field
centering and Köhler
illumination
CENTERING THE CONDENSER AND KÖHLER ILLUMINATION
These (2) must be adjusted each time the microscope is used and each time the objective is changed.
condenser and field diaphragms
CENTERING THE CONDENSER AND KÖHLER ILLUMINATION
Familiarize the steps in centering the condenser and kohler illumination
- Place a slide on the stage and focus the object using the low-power objective with the condenser raised
- Close the field diaphragm
- Lower the condenser until the edges of the field diaphragm are sharply focused
- Center the image of the field diaphragm with the condenser centering screws
- Open the field diaphragm until its image is at the edge of the field
- Adjust the aperture diaphragm until approximately 75% of the field is visible (OR Remove an eyepiece and look down through the eyepiece tube; OR replace eyepiece)
CENTERING THE CONDENSER AND KÖHLER ILLUMINATION
T or F
The microscope should always be covered when not in use to protect it from dust
T
CENTERING THE CONDENSER AND KÖHLER ILLUMINATION
If any optical surface becomes coated with dust, it should be carefully removed with a?
camel-hair brush
CENTERING THE CONDENSER AND KÖHLER ILLUMINATION
Optical surfaces should be cleaned with ?
lens paper
CENTERING THE CONDENSER AND KÖHLER ILLUMINATION
Clean any contaminated lens immediately with a?
commercial lens cleaner
CENTERING THE CONDENSER AND KÖHLER ILLUMINATION
T or F
An oil immersion lens must be wiped free of oil and cleaned after each use
T
CENTERING THE CONDENSER AND KÖHLER ILLUMINATION
T or F
Light sources are replaced as necessary
T
CENTERING THE CONDENSER AND KÖHLER ILLUMINATION
T or F
A monthly professional cleaning for the microscope is recommended
F (annual professional cleaning)
TYPES OF MICROSCOPY
- Most frequently used in the clinical laboratory routine urinalysis
- Objects appear dark against a light background
- light source emitting light in the visible wavelength range
Bright-Field Microscopy
TYPES OF MICROSCOPY
T or F
Use of bright-field microscopy for the examination of urine sediment can present problems when the amount of light reaching the specimen is not properly controlled
T
T or F
Sediment constituents with a low refractive index will
be observed properly when subjected to light of high intensity
F (Sediment constituents with a low refractive index will be overlooked when subjected to light of high intensity)
Subdued light is needed to see the more translucent
formed elements of the urine such as?
hyaline casts, crystals and mucus threads
T or F
In bright field microscope, light is controlled by adjusting the rheostat on the light source, not by lowering the condenser
T
Bright field microscope point of reference?
Epithelial cell
T or F
Staining of the sediment blurs the visualization of these elements when using bright-field microscopy
F (Staining of the sediment also increases the visualization of these elements when using bright-field microscopy)
T or F
One should avoid focusing on artifacts and should not examine objects in wrong plane
T
- light that does not pass through the specimen is shifted one quarter of a wavelength and compared with the phase difference of the specimen
- detection of more translucent or low-refractile formed elements and living cells (hyaline casts, mucous threads, mixed cellular casts and Trichomonas)
- Hardens the outlines of even the most transparent formed elements
Phase-Contrast Microscopy
Phase-Contrast Microscopy
2 components of phase-contrast microscopy which enhances contrast and improve the visibility and definition of structures having a refractive index like that of the urine
phase-contrast objective
lens and a matching condenser
Phase-Contrast Microscopy
appear as “targets” are placed in the
condenser and the objective
Two phase rings
Phase-Contrast Microscopy
is placed in the condenser or below it, permitting light to only pass through the central clear circular area
One phase ring
Phase-Contrast Microscopy
with a central circular area that retards the light by one
quarter wavelength is placed in the objective
second phase-shifting ring
Phase-Contrast Microscopy
What are the two phase rings used?
Phase objective ring (Phase plate or dark annulus), Condenser ring (light annulus)
Phase-Contrast Microscopy
Phase plate or dark annulus
Phase objective ring
Phase-Contrast Microscopy
light annulus
Condenser ring
Phase-Contrast Microscopy
Light passes to the specimen through the clear circle in the phase ring in the condenser, forming what?
halo of light around
the specimen
Phase-Contrast Microscopy
when light rays pass through an object, they are slowed compared to the light passing through the air (media) so the intensity of light is decreased producing a contrast
Phase difference
Phase-Contrast Microscopy
T or F
Phase difference is when light rays pass through an object, they are faster compared to the light passing through the air (media) so the intensity of light is increased producing a contrast
F (when light rays pass through an object, they are slowed compared to the light passing through the air (media) so the intensity of light is decreased producing a contrast)
Phase-Contrast Microscopy
when the light that does not pass through the specimen is shifted one quarter of a wavelength and compared with the phase difference of the specimen
Best contrast
Phase-Contrast Microscopy
T or F
Best contrast is when the light that does not pass through the specimen is shifted one quarter of a wavelength and compared with the phase difference of the specimen
T
Phase-Contrast Microscopy
T or F
Phase rings must be different
F (Phase rings must match)
it is important to check that the objective and condenser mode are the same
Phase-Contrast Microscopy
T or F
The diameter of the rings varies with the magnification
T
Phase-Contrast Microscopy
The image has the best contrast when the background is ?
darkest
Phase-Contrast Microscopy
must be adjusted to have maximum
contrast and make them concentric
Phase-contrast rings
Phase-Contrast Microscopy
enters the central circle of the phase-shifting ring, and all other light is moved one quarter of a wavelength out of phase
diffracted light
- aids in the identification of crystals and lipids
Polarizing Microscopy
Polarizing Microscopy
These (2) substances have the ability to rotate the path of the unidirectional polarized light beam to produce
characteristic colors in crystals and Maltese cross
formation in lipids
Crystals and Lipids
Polarizing Microscopy
Bidirectional polarized light
a. polarizing microscopy
b. phase-contrast microscopy
c. both
d. neither
d. neither
polarizing microscopy rotates path of unidirectional polarized light beam
Polarizing Microscopy
identify what substance:
produce characteristic colors
crystals
Polarizing Microscopy
identify what substance:
Maltese cross formation
lipids
Polarizing Microscopy
What specific fat substance produces maltese cross formation
Cholesterol (droplets)
Polarizing Microscopy
- Circles divided into 4 quadrants by a bright Maltese style cross against a black background
- Differentiates crystals and fibers from cellular or protein cast materials
- seen under polarized light microscopy
are birefringent
Cholesterol (droplets)
Polarizing Microscopy
These granules also produce Maltese-cross pattern
Starch granules
Polarizing Microscopy
Maltese corss formation of triglycerides are seen or not seen?
not seen
Polarizing Microscopy
A property of fat which indicates hat the element can refract light in two dimensions at 90 degrees to each
other.
birefringent
Polarizing Microscopy
Light source in polarizing microscopy that produces light
rays of many different waves. Each wave has a distinct
direction and a vibration perpendicular to its direction
halogen quartz lamp
Polarizing Microscopy
Aside from halogen quartz lamp, what are the other (2) components in polarizing microscopy?
polarizer and an analyzer
Polarizing Microscopy
Where is the analyzer located
between the objectives and the ocular
OO
Polarizing Microscopy
where is the polarizing filter located?
condenser filter holder
Polarizing Microscopy
T or F
Polarized light vibrates in the same plane or direction
T
Polarizing Microscopy
T or F
Polarizing microscopy is when light passes through a birefringent substance, it splits into two beams, one beam rotated 90 degrees to the other
T
Polarizing Microscopy
A substance that rotates the plane of polarized light 90
degrees in a clockwise direction is said to have? (positive or negative birefringence)
positive birefringence
Polarizing Microscopy
a substance that rotates the plane in a
counterclockwise direction has? (positive or negative birefringence)?
negative birefringence
No light will reach the analyzer filter; object appears black.
Polarizing Microscopy
T or F
Polarized light is obtained by using two polarizing filters
T
Polarizing Microscopy
T or F
The light emerging from one filter vibrates in one plane, and a second filter placed at a 90-degree angle allows all light to pass through
F (light emerging from one filter vibrates in one plane, and a second filter placed at a 90-degree angle blocks all incoming light, except that rotated by the birefringent substance)
Polarizing Microscopy
filters are in opposite directions
crossed configuration
Polarizing Microscopy
An additional filter can be added which divides the
light entering the microscope into slow and fast vibrations
red compensated polarizing filter
Polarizing Microscopy
These sediments can be more easily identified by aligning them with the slow vibration and observing the blue or yellow color they produce
Crystals
Polarizing Microscopy
properties of a material are the same in all
directions
Isotropic
Polarizing Microscopy
when the properties of a material vary with
different orientation
Anisotropic
Polarizing Microscopy
T or F
Polarizing microscopy is used in urinalysis to confirm the
identification of fat droplets, oval fat bodies, and fatty
casts that produce a characteristic Maltese cross pattern
T
Polarizing Microscopy
Identify if seen or not seen in polarizing microscopy:
CaOx, Fibers, Amorphous crystals, Cholesterol,
Starch granules, Uric acid
Seen
Polarizing Microscopy
Identify if seen or not seen in polarizing microscopy:
Cells (RBC, WBC), Casts, Bacteria, Triglycerides
not seen
Polarizing Microscopy
- Provides a three-dimensional image showing very fine structural detail by splitting the light ray so that the beams pass through different areas of the specimen
- layer-by-layer imaging of a specimen and
enhanced detail for specimens with either a low or high
refractive index.
Interference-Contrast Microscopy
- object appears bright against a dark background but without the diffraction halo associated with phase contrast microscopy
- More extensive modifications to the bright-field microscope are required to perform this technique, not routinely used in the urinalysis laboratory
Interference-Contrast Microscopy
Interference-Contrast Microscopy
Two types of interference-contrast miscroscopy?
- Modulation contrast (Hoffman)
- Differential-interference contrast (Nomarski)
Interference-Contrast Microscopy
Uses split aperture, polarizer, filter
Two types of interference-contrast miscroscopy
Modulation contrast (Hoffman)
Interference-Contrast Microscopy
Familiarize concept of Modulation contrast (hoffman)
Two types of interference-contrast miscroscopy
- Split aperture is placed below the condenser
- Polarizer is placed below the split aperture
- Amplitude filter is placed in back of each objective.
Interference-Contrast Microscopy
three zones of light
transmission of Modulation contrast (Hoffman)
Two types of interference-contrast miscroscopy
Dark zone, Gray zone, Clear zone
Interference-Contrast Microscopy
transmits 1% of light
three zones of light transmission of Modulation contrast (Hoffman)
dark zone
Interference-Contrast Microscopy
transmits 15% of light
three zones of light transmission of Modulation contrast (Hoffman)
gray zone
Interference-Contrast Microscopy
transmits 100% of light
three zones of light transmission of Modulation contrast (Hoffman)
clear zone
Interference-Contrast Microscopy
Uses Wollaston prism and Polarizing filter
Differential-interference contrast (Nomarski)
Interference-Contrast Microscopy
Familiarize concept of Differential-interference contrast (Nomarski)
- A polarizing filter to output plane-polarized light is placed between the light source and the condenser
- A two-layered Nomarski-modified Wollaston prism that separates individual rays of light into ray pairs is required
- The lower Wollaston prism is built into the condenser of the microscope
- The upper prism is placed between the objective and the eyepiece and recombines the rays
- Above the top Wollaston prism, another polarizing filter is placed that causes wave interference to occur and produce the three-dimensional
- enhance visualization of specimens that cannot be seen easily viewed with a bright-field microscope
- often used for unstained specimens, and, in particular, to identify the spirochete Treponema pallidum
- Indirect light is reflected off the object
Dark-field Microscopy
Dark-field Microscopy
The condenser of bright-field microscope is replaced with?
dark-field condenser that contains an opaque disk
- used to detect bacteria and viruses within cells and
tissues through a technique called immunofluorescence - allows the visualization of naturally fluorescent substances or those that have been stained with a fluorochrome or fluorophore (fluorescent dyes) to produce an image
Fluorescence Microscopy
Fluorescence Microscopy
- is the property by which some atoms absorb light at a particular wavelength and subsequently emit light of a longer wavelength, termed fluorescence lifetime
- Detects specific wavelengths of light emitted from
objects
Fluorescence
Fluorescence Microscopy
Fluorescent substances absorb the energy and emit a longer wavelength of light that is visualized with the use of special filters called the?
excitation filter and the emission filter
Fluorescence Microscopy
(excitation filter or emission filter)
selects the excitation wavelength of
light from a light source.
excitation filter
Fluorescence Microscopy
(excitation filter or emission filter)
selects a specific wavelength of
emitted light from the specimen to become visible
emission filter
Fluorescence Microscopy
T or F
The filters are chosen to be different from the excitation and emission wavelengths of the fluorophore used to label the specimen
F (The filters are chosen to match the excitation and
emission wavelengths of the fluorophore used to label the specimen)
Fluorescence Microscopy
reflects the excitation light to the specimen
and transmits the emitted light to the emission filter, which is collected with the objective and imaged by the detector
dichroic mirror
Fluorescence Microscopy
T or F
The fluorescent substancecan be observed in the fluorescent microscope as a bright object against a dark background with high contrast when ultraviolet light source is used.
T
Fluorescence Microscopy
Powerful light sources required for this
mercury or xenon arc lamps
Identify what type of microscope based from function and features
Function: Routine urinalysis
Bright-field
Identify what type of microscope based from function and features
Function: Elements w/ low RI Transparent
Features: Phase objective ring, Condenser ring
Phase-contrast
Identify what type of microscope based from function and features
Function: Anisotropic elements, Birefringent crystals, Lipids
Features: Phase objective ring, Condenser ring
Polarizing
Identify what type of microscope based from function and features
Function: T. pallidum
Features: Dark-field condenser
Dark-field
Identify what type of microscope based from function and features
Function: Fluorescent microorganisms
Features: Fluorescent dye, Special filters
Fluorescence
Identify what type of microscope based from function and features
Function: 3D image, Layer by layer image
Features: Wollaston prism, Polarizing filter
Differential-interference contrast
- estimate of the formed elements (RBC, WBC, epithelial cells and cast) and protein content of urine specimen
- First procedure to standardize the quantitation of formed elements in urine microscopic analysis
Addis count
ADDIS COUNT
Specimen in addis count
12-hour urine
ADDIS COUNT
Reference value for RBC
0 to 500,000
ADDIS COUNT
Reference value for WBCs and Epithelial Cells
0 to 1,800,000
ADDIS COUNT
Reference value for hyaline casts
0 to 5,000