Microscopic Examination of Urine | from Strasinger (6th ed.) Flashcards
What is the 3rd part of routine UA (after physical and chemical examination)?
Microscopic examination (of urinary sediment)
What is the purpose of microscopic examination of the urinary sediment?
To detect and to identify insoluble materials present in the urine
What contributes formed elements to the urine?
1) Blood
2) Kidney
3) Lower genitourinary tract
4) External contamination
What are the formed elements (w/c are contributed by blood, kidney, lower GUT, and external contamination) in the urine?
1) RBCs
2) WBCs
3) Epithelial cells
4) Casts
5) Bacteria
6) Yeast
7) Parasites
8) Mucus
9) Spermatozoa
10) Crystals
11) Artifacts
True or False
All of the formed elements in the urine are clinically significant and others are considered abnormal
False, because some of the formed elements in the urine are of no clinical significance and others are considered normal
Some of the formed elements are of no clinical significance and others are considered normal unless what?
Unless they are present in increased amts
What must be included in the examination of the urinary sediment?
It must include both identification and quantitation of the elements present
Microscopic analysis is subject to several procedural variations including what methods?
Including the methods by w/c:
1) The sediment is prepared
2) The volume of sediment actually examined
3) The methods used to obtain visualization
4) The equipment used to obtain visualization
5) The manner in w/c the results are reported
True or False
Protocols have been developed to increase the standardization and cost-effectiveness of microscopic UA
True
What is done by many labs to enhance the cost-effectiveness of UA?
Many labs have developed protocols
What are the protocols developed by many labs (to enhance the cost-effectiveness of UA)?
Microscopic examination of the urine sediment is performed only on sxs meeting specified criteria
True or False
Abnormalities in the physical and chemical portions of the UA play a primary role in the decision to perform a microscopic analysis, thus the use of the term “macroscopic screening”
True
What are the parameters that are considered significant (w/c vary among labs)?
It usually include:
1) Color
2) Clarity
3) Blood
4) Protein
5) Nitrite
6) LE
7) Glucose (possibly)
True or False
Lab-designed criteria can also be programmed into automated instruments
True
True or False
Percentages of abnormal sxs that would go undetected using parameters differ significantly among studies
True
True or False
It is okay to not consider pt population when developing protocols for macroscopic screening
False, because pt population must also be considered when developing protocols for macroscopic screening
Who are the individuals / population that must also be considered when developing protocols for macroscopic screening?
1) Pregnant women
2) Pediatric
3) Geriatric
4) Diabetic
5) Immunocompromised
6) Renal pts
What is the meaning of CLSI?
Clinical and Laboratory Standards Institute
What does CLSI recommend w/ regards to when should microscopic examination be performed?
It recommends that microscopic examination be performed when:
1) Requested by a physician
2) A lab specified pt population is being tested
3) Any abnormal physical or chemical result is obtained
When should sxs be examined?
Sxs should be examined while:
1) Fresh
2) Or adequately preserved
What are the primary formed elements that disintegrate rapidly (particularly in dilute alkaline urine)?
1) RBCs
2) WBCs
3) Hyaline casts
Refrigeration of sxs may cause what?
It may cause precipitation of:
1) Amorphous urates
2) Amorphous phosphates
3) Other nonpathologic crystals
What is the action of amorphous urates and phosphates and other nonpathologic crystals (w/c are present when the sx is refrigerated)?
These can obscure other elements in the urine sediment
What may be the action of warming the sx to 37 DC (prior to centrifuging)?
It may dissolve some of the crystals (other nonpathologic crystals)
What is the method of urine collection that minimizes external contamination of the sediment?
Midstream clean-catch
As w/ physical and chemical analyses, what type of sx can cause false-(-) readings?
Dilute random sxs
What must be done prior to decanting a portion (of sx) into the centrifuge tube?
Care must be taken to thoroughly mix the sx
What is the usual std amt of urine (this is also the volume of urine w/c is centrifuged in a conical tube)?
Between 10 and 15 mL
What is the aid of using 10 - 15 mL of urine (and centrifuging it)?
It provides an adequate volume from w/c to obtain a representative sx of the elements present in the sx
What is the volume of urine that is frequently used?
12 mL
What are the reasons for why is 12 mL volume of urine frequently used?
1) Because multiparameter rgnt strips are easily immersed in this volume
2) Because capped centrifuge tubes are often calibrated to this volume
When is obtaining a 12 mL sx not possible?
For pediatric pts
What should be done if obtaining 12 mL sx is not possible?
The volume of sx used should be noted on the report form
What is the aid of noting the volume used (specifically if obtaining 12 mL sx is not possible) in the report form?
This allows the physician to correct the results
What is done by some labs when obtaining 12 mL urine is not possible?
Some labs choose to make the correction prior to reporting
Provide an ex of the application of correction being done (if obtaining 12 mL urine is not possible)
If 6 mL of urine is centrifuged, the results are multiplied by 2
True or False
It is okay even if the speed of the centrifuge and length of time the sx is centrifuged are not consistent
False, because the speed of the centrifuge and length of time the sx is centrifuged should be consistent
What is the meaning of RCF?
Relative centrifugal force
What is the meaning of RPM?
Revolutions per minute
What is the action of centrifugation for 5 mins at a RCF of 400?
It produces an optimum amt of sediment w/ the least chance of damaging the elements
What should be used to correct for differences in the diameter of centrifuge heads?
RCF rather than RPM should be used
Where is the RPM value shown?
On the centrifuge tachometer
What should be used to convert RPM value to RCF?
Use nomograms (w/c are available in many lab manuals) or by using the formula:
RCF = 1.118 x 10^-5 x radius in centimeters x PRM^2
True or False
It is okay to not routinely perform centrifuge calibration
False, because centrifuge calibration should be routinely performed
What can be used to slow the centrifuge?
Braking mechanism
The use of braking mechanism to slow the centrifuge causes what?
It causes disruption of the sediment prior to decantation
Based on the effect caused by the braking mechanism to slow the centrifuge, should braking mechanism be used / done?
No
What should be done to prevent biohazard aerosols?
All sxs must be centrifuged in capped tubes
What is/are the significance of the given screening test (in macroscopic screening and microscopic correlations)?
Given screening test: Color
Blood
What is/are the significance of the given screening test (in macroscopic screening and microscopic correlations)?
Given screening test: Clarity
1) Hematuria vs. hgburia / myoglobinuria
2) Confirm pathologic or nonpathologic cause of turbidity
What is/are the significance of the given screening test (in macroscopic screening and microscopic correlations)?
Given screening test: Blood
1) RBCs
2) RBC casts
What is/are the significance of the given screening test (in macroscopic screening and microscopic correlations)?
Given screening test: Protein
1) Casts
2) Cells
What is/are the significance of the given screening test (in macroscopic screening and microscopic correlations)?
Given screening test: Nitrite
1) Bacteria
2) WBCs
What is/are the significance of the given screening test (in macroscopic screening and microscopic correlations)?
Given screening test: LE
1) WBCs
2) WBC casts
3) Bacteria
What is/are the significance of the given screening test (in macroscopic screening and microscopic correlations)?
Given screening test: Glucose
Yeast
What should remain in the tube after decantation?
Uniform amt of:
1) Urine
2) Sediment
What are the volumes that are frequently used (in terms of sediment preparation)?
1) 0.5 mL
2) 1.0 mL
What is the computation for sediment preparation?
Volume of urine centrifuged divided by the sediment volume = conc. factor
What is the conc. factor (via the use of computation) if the volume of the sediment is 0.5 mL?
24
What is the conc. factor (via the use of computation) if the volume of the sediment is 1.0 mL?
12
The sediment conc. factor relates to what?
To the probability of detecting elements present in low quantities
When is sediment conc. factor used?
It is used when quantitating the # of elements present per milliliter
What should be done (in terms of sediment preparation) to maintain a uniform sediment conc. factor?
The urine should be aspirated off rather than poured off
Aspiration > pouring
When can pouring of urine (in terms of sediment preparation) be done instead of aspiration?
If specified by the commercial system in use
True or False
All systems provide pipettes for the purpose of aspirating urine (rather than pouring it off | in terms of sediment preparation)
False, because some systems provide pipettes for the purpose of aspirating urine (rather than pouring it off | in terms of sediment preparation)
What are the other uses of pipettes (w/c are provided by some systems for aspirating urine | in terms of sediment preparation)?
1) These are also used for sediment resuspension
2) Also, these are used for transferring sxs to the slide
What must be done to the sediment (when it is already prepared)?
It must be thoroughly resuspended
How to thoroughly resuspend the sediment (after preparation)?
Via gentle agitation
What are the ways on how to thoroughly resuspend the sediment (after preparation)?
1) Via the use of a commercial-system pipette
2) Or by repeatedly tapping the tip of the tube (via the use of finger)
Can vigorous agitation be done to thoroughly resuspend the sediment (after preparation)?
No, it should be avoided
Why should vigorous agitation be avoided when thoroughly resuspending the sediment?
Because it may disrupt some cellular elements
Why is thorough suspension (of the sediment) essential?
To provide equal distribution of elements in the microscopic examination fields
True or False
It is okay to not be consistent on the volume of sediment (for each sx) placed on the microscope slide
False, because the volume of sediment placed on the microscope slide should be consistent for each sx
When using the conventional glass-slide method, what is the recommended volume of sx (/ sediment) and what should be done to this volume of sediment?
20 uL (0.02 mL) w/c should be covered by a 22 x 22 mm glass cover slip
What may be the result of allowing the sx (/ sediment) to flow outside of the coverslip (if the conventional glass-slide method is used)?
It may result in loss of heavier elements (such as casts)
What is the difference between the application of conventional glass-slide method and commercial systems (when it comes to the volume of the sediment to be examined)?
Commercial systems control the volume of sediment examined
How do commercial systems control the volume of sediment examined?
By providing slides w/ chambers w/c are capable of containing a specified volume
What should be done when commercial systems are used (in terms of the volume of sediment examined)?
Care must be taken to ensure the chambers are completely filled
What are the info that the product literature supply?
1) Chamber volume
2) Size of the viewing area
3) Approx # of low-power viewing areas
4) Approx # of high-power viewing areas
This are all based on the area of the field of view using a std microscope
The information (supplied by the product literature) together w/ the sediment conc. factor are necessary to what?
To quantitate cellular elements per milliliter of urine
What is the conventional method of examining the urine sediments?
1) Place a drop of centrifuged urine on a glass slide
2) Add a cover slip
3) Examine the sediment microscopically
The conventional method of examining the urine sediments has been substantially improved through what?
Through the use of commercial slide systems
What does the CLSI recommend (in terms of examination of urine sediments)?
It recommends the use of commercial slide systems together w/ the standardization of all phases of the methodology, including the conventional method
What are the systems that are currently available (in connection w/ examination of urine sediments)?
1) KOVA
2) Urisystem
3) Count-10
4) Quick-Prep Urinalysis System
5) CenSlide 2000 Urinalysis System
6) R/S Workstations 1000, 2000, 2003
What are the variety of options that are provided by systems (in terms of examination of urine sediments)?
1) Capped, calibrated centrifuge tubes
2) Decanting pipettes to control sediment volume
3) Slides that control the amt of sediment examined
4) Produce a consistent monolayer of sediment for examination
5) Provide calibrated grids for more consistent quantitation
The Cen-Slide and R/S Workstations do not require what?
It do not require manual loading of the centrifuged sx onto a slide and are considered closed systems that minimize exposure to the sx
Cen-Slide provides a what?
It provides a specially designed tube that permits direct reading of the urine sediment
The R/S Workstations consist of what?
It consist of a glass flow cell into w/c urine sediment is pumped, microscopically examined, and then flushed from the system
Microscopic examination (of the sediment) should be performed in what manner?
It should be performed in a consistent manner
What is the minimum # of fields (both low and high power) that should be observed when examining the sediment?
10
What is the magnification in low power field?
10x
What is the magnification in high power field?
40x
What is the method of examining the sediment?
1) The slide is 1st examined under low power
2) When elements (such as casts) that require identification are encountered, the setting is changed to high power
What are the reasons for why is the slide 1st examined under low power?
1) To detect casts
2) To ascertain the general composition of the sediment
What is the characteristic of casts (when conventional glass-slide method is used | during examination of sediment)?
They have a tendency to locate near the edges of the cover slip
Due to the characteristic of casts (when conventional glass-slide method is used | during examination of sediment), what is recommended to be done?
Low-power scanning of the cover-perimeter is recommended
Does the characteristic of casts (when conventional glass-slide method is used | during examination of sediment) occur when using standardized commercial systems?
No
What is the characteristic of many sediment constituents when the sediment is examined unstained?
They have a refractive index similar to urine
Due to the characteristic of many sediment constituents (when the sediment is examined unstained), what is essential to be done?
It is essential to examine sediments under reduced light when using bright-field microscopy
True or False
Initial focusing can be difficult w/ a fluid sx
True
True or False
Care must be taken to ensure that the examination is being performed in the correct plane
True
What is the urinary sediment that will often be present to provide a point of reference?
Epithelial cell
True or False
Focusing on artifacts should be avoided
True
What are the reasons why should focusing on artifacts be avoided?
1) Because they are often larger than the regular sediment elements
2) Because it can cause the microscopist to examine objects in the wrong plane
Continuous focusing w/ the fine adjustment aids in what?
It aids in obtaining a complete representation of the sediment constituents
True or False
The terminology and methods of reporting may differ slightly among labs but must be consistent within a particular lab system
True
How are casts routinely reported?
These are reported as the average # per low-power field (lpf) following examination of 10 fields
How are RBCs and WBCs routinely reported?
These are reported as the average # per 10 high-power fields (hpf)
What is the manner of frequent reporting of epithelial cells, crystals, and other elements?
Semiquantitatively
How are epithelial cells, crystals, and other elements frequently reported (semiquantitatively)?
1) Rare
2) Few
3) Moderate
4) Many
This should follow lab format as to lpf or hpf use
How is the other manner of reporting epithelial cells, crystals, and other elements reported?
1) 1+
2) 2+
3) 3+
4) 4+
This should follow lab format as to lpf or hpf use
What must labs also do in terms of reporting epithelial cells, crystals, and other elements?
Labs must also determine their particular reference values based on the sediment conc. factor in use
Provide an ex of where labs determine the particular reference values of sediments based on the sediment conc.
For Urisystem, w/ a conc. factor of 30, states a reference value for WBCs of 0 - 8/hpf as opposed to the conventional value of 0 - 5/hpf used w/ a conc. factor of 12
Converting the ave # of elements per lpf or hpf to the # per milliliter provides what?
It provides standardization among the various techniques in use
What are the steps for converting the ave # of elements per lpf or hpf to the # per milliliter?
1) Calculating the area of an lpf / hpf for the microscope in use using the manufacturer-supplied field of view diameter and the formula: πr^2 = area
2) Calculating the maximum # of lpfs or hpfs in the viewing area
3) Calculating the # of hpfs per milliliter of urine tested using the conc. factor and the volume of sediment examined
4) Calculating the # of formed elements per milliliter of urine by multiplying the # of hpfs per milliliter by the ave # of formed elements per field
True or False
In converting the ave # of elements per lpf or hpf to the # per milliliter, provided the same microscope and volume of sediment examined are used, the number of lpfs and hpfs per mL of urine remains the same, thereby simplifying the calculation
True
True or False
Labs should evaluate the advantages and disadvantages of adding an additional calculation step to the microscopic examination
True
What does CLSI state in terms of reporting (in microscopic examination)?
It states that all decisions w/ regard to reporting of the microscopic should be based on the needs of the individual lab
True or False
Procedures (in terms of reporting [in microscopic examination]) should be completely documented and followed by all personnel
True
What should be done to the microscopic results?
These should be correlated w/ the physical and chemical findings
What is the aid of correlating microscopic results w/ the physical and chemical findings?
To ensure the accuracy of the report
What should be done to sxs if the microscopic results does not correlate w/ the physical and chemical findings?
The sxs must be rechecked for both technical and clerical errors
True or False
The amt of formed elements or chemicals must also be considered, as must the possibility of interference w/ chemical tests and the age of the sx (in terms of correlating microscopic results)
True
Answer the ff questions w/ regards to the given microscopic element:
1) What is/are the correlation/s for physical findings?
2) What is/are the correlation/s for chemical findings?
3) What is/are the exception/s?
Given microscopic element: RBCs
1) Turbidity
1. 1) Red color
2) + Blood
2. 1) + Protein
3) Number
3. 1) Hemolysis
Answer the ff questions w/ regards to the given microscopic element:
1) What is/are the correlation/s for physical findings?
2) What is/are the correlation/s for chemical findings?
3) What is/are the exception/s?
Given microscopic element: WBCs
1) Turbidity
2) + Protein
2.1) + Nitrite
2.2) + LE
3) Number
3,1) Lysis
Answer the ff questions w/ regards to the given microscopic element:
1) What is/are the correlation/s for physical findings?
2) What is/are the correlation/s for chemical findings?
3) What is/are the exception/s?
Given microscopic element: Epithelial cells
1) Turbidity
3) Number
Answer the ff questions w/ regards to the given microscopic element:
1) What is/are the correlation/s for physical findings?
2) What is/are the correlation/s for chemical findings?
3) What is/are the exception/s?
Given microscopic element: Casts
2) + Protein
3) Number
Answer the ff questions w/ regards to the given microscopic element:
1) What is/are the correlation/s for physical findings?
2) What is/are the correlation/s for chemical findings?
3) What is/are the exception/s?
Given microscopic element: Bacteria
1) Turbidity 2 Increased / high pH 2.1) + Nitrite 2.2) + Leukocytes 3) Number and type
Answer the ff questions w/ regards to the given microscopic element:
1) What is/are the correlation/s for physical findings?
2) What is/are the correlation/s for chemical findings?
3) What is/are the exception/s?
Given microscopic element: Crystals
1) Turbidity
1. 1) Color
2) pH
2. 1) Bilirubin
3) Number and type
True or False
Many factors can influence the appearance of the urinary sediment
True
What are the factors that can influence the appearance of the urinary sediment?
1) Cells (in various stages of development and degeneration)
2) Casts (in various stages of development and degeneration)
3) Distortion of cells and crystals by the chemical content of the sx
4) Presence of inclusions in cells and casts
5) Contamination by artifacts
True or False
Since many factors can influence the appearance of the urinary sediment, identification can sometimes be difficult even for experienced lab personnel
True
How to enhance identification?
It can be enhanced through the use of:
1) Sediment stains
2) Different types of microscopy
What is the actions / purposes of staining?
1) It increases the overall visibility of sediment elements being examined using bright-field microscopy by changing their refractive index
2) It also imparts identifying characteristics to cellular structures such as:
a. Nuclei
b. Cytoplasm
c. Inclusions
Do hyaline casts have a refractive index very similar to that of urine?
Yes
What is the most frequently used stain in UA?
Sternheimer-Malbin stain
What are the components that comprise Sternheimer-Malbin stain?
1) Crystal violet
2) Safranin O
True or False
Sternheimer-Malbin stain is available commercially under a variety of names
True
Sternheimer-Malbin stain are under what names (since it is available commercially)?
1) Sedi-Stain
2) KOVA stain
What does commercial brands contain?
Stabilizing chemicals
What is the action of stabilizing chemicals (w/c are contained in commercial brands)?
These prevent the precipitation that occurred w/ the original stain
What are the sediments that absorb the dye (/ Sternheimer-Malbin stain) well?
1) WBCs
2) Epithelial cells
3) Casts
What is the effect of Sternheimer-Malbin stain to WBCs, epithelial cells, and casts?
A clearer delineation of structure and contrasting colors of the nucleus and cytoplasm are provided
What is 0.5% solution of toluidine blue?
It is a metachromatic stain
What is the action of 0.5% solution of toluidine blue?
It provides enhancement of nuclear detail
What are the uses of 0.5% solution of toluidine blue?
1) It can be useful in the differentiation between WBCs and renal tubular epithelial cells
2) It is also used in the examination of cells from other body fluids
What is the action of 2% acetic acid to the sediment?
It enhances the nuclear detail
Can addition of 2% acetic acid (to enhance the nuclear detail) be done for initial sediment analysis? Why or why not?
No, because RBCs are lysed by the acetic acid
The passage of lipids across the glomerular membrane results in what?
It results in the appearance of free fat droplets and lipid-containing cells and casts in the urinary sediment
What are the lipids that can pass across the glomerular membrane?
1) Triglycerides
2) Neutral fats
3) Cholesterol
What are the exs of lipid stains?
1) Oil Red O
2) Sudan III
What can be used to confirm the presence of lipids (such as TAG, neutral fats, and chole)?
1) Oil Red O
2) Sudan III
3) Polarizing microscopy
What is the action of TAG and neutral fats in the presence of lipid stains?
They stain orange-red
What is the action of chole in the presence of lipid stains?
It does not stain (but it is capable of polarization)
What are the characteristics of TAG, neutral fats, and chole?
1) They can pass across the glomerular membrane
2) They are usually present concurrently in the sediment
Since TAG, neutral fats, and chole are usually present concurrently in the sediment, what are permitted to be used for their confirmation?
The use of either staining or polarization for their confirmation is permitted
Where is Gram stain primarily used?
In the microbiology section (for the differentiation between gram-[+] and gram-[-] bacteria)
What is the color of gram-(+) bacteria (via the use of Gram stain)?
Blue
What is the color of gram-(-) bacteria (via the use of Gram stain)?
Red
What is the role of Gram stain in routine UA?
Its role is limited to the identification of bacterial casts
What is the problem in terms of the identification of bacterial casts?
Bacterial casts can easily be confused w/ granular casts
What must be used when performing Gram stain?
A dried, heat-fixed preparation of the urine sediment
Polynuclear WBCs seen in the urinary sediment are almost always what type of WBC?
Neutrophils
What is the characteristic of neutrophils (as seen in the urinary sediment)?
These are associated w/ microbial infection
What type of WBCs are present in the sediment in cases of a drug-induced allergic rxn producing inflammation of the renal interstitium?
Eosinophils
What is the preferred stain for urinary eosinophils?
Hansel stain
What are the components comprised in Hansel stain?
1) Methylene blue
2) Eosin Y
What is the other stain that can also be used for urinary eosinophils?
Wright’s stain
Where is staining performed?
On a:
1) Dried smear (of the centrifuged sx)
2) Or cytocentrifuged preparation (of the sediment)
What may be seen after episodes of hgburia?
Yellow-brown granules
Where may yellow-brown granules be seen (after episodes of hgburia)?
1) In renal tubular epithelial cells
2) In casts
3) Free-floating (in the urine sediment)
What is the term called to the yellow-brown granules w/c may be seen in renal tubular epithelial cells, casts, or free-floating in the urine sediment (w/c may be present after episodes of hgburia)?
Hemosiderin
What is the stain used to confirm that the yellow-brown granules (w/c may be present after episodes of hgburia) are hemosiderin?
Prussian blue stain (for iron)
What is the action of Prussian blue stain (for iron) if hemosiderin granules are present?
It stains the hemosiderin granules a blue color
Answer the ff questions w/ regards to the given stain:
1) What is/are the action/s?
2) What is/are the fxn/s?
Given stain: Sternheimer-Malbin
1) Delineates structure; contrasting colors of the nucleus and cytoplasm
2) Identifies WBCs, epithelial cells, and casts
Answer the ff questions w/ regards to the given stain:
1) What is/are the action/s?
2) What is/are the fxn/s?
Given stain: Toluidine blue
1) Enhances nuclear detail
2) Differentiates WBCs and renal tubular epithelial (RTE) cells
Answer the ff questions w/ regards to the given stain:
1) What is/are the action/s?
2) What is/are the fxn/s?
Given stain: 2% acetic acid
1) Lyses RBCs; enhances nuclei of WBCs
2) Distinguishes RBCs from WBCs, yeast, oil droplets, and crystals
Answer the ff questions w/ regards to the given stain:
1) What is/are the action/s?
2) What is/are the fxn/s?
Given stain: Lipid stains (Oil Red O and Sudan III)
1) Stain TAG and neutral fats orange-red; do not stain chole
2) Identify free fat droplets and lipid-containing cells and casts
Answer the ff questions w/ regards to the given stain:
1) What is/are the action/s?
2) What is/are the fxn/s?
Given stain: Gram stain
1) Differentiates gram-(+) and gram-(-) bacteria
2) Identifies bacterial casts
Answer the ff questions w/ regards to the given stain:
1) What is/are the action/s?
2) What is/are the fxn/s?
Given stain: Hansel stain
1) Methylene blue and eosin Y contains eosinophilic granules
2) Identifies urinary eosinophils
Answer the ff questions w/ regards to the given stain:
1) What is/are the action/s?
2) What is/are the fxn/s?
Given stain: Prussian blue stain
1) Stains structures containing iron
2) Identifies yellow-brown granules of hemosiderin in cells and casts
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: RBCs
1) Neutral - pink to purple; acid - pink (unstained); alkaline - purple
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the nuclei of stained elements?
2) What is/are the usual distinguishing color/s of the cytoplasm of stained elements?
3) What is/are the comment/s?
Given element in urinary sediment: WBCs (dark-staining cells)
1) Purple
2) Purple granules
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the nuclei of stained elements?
2) What is/are the usual distinguishing color/s of the cytoplasm of stained elements?
3) What is/are the comment/s?
Given element in urinary sediment: Glitter cells (Sternheimer-Malbin positive cells)
1) Colorless / light blue
2) Pale blue / gray
3) Some glitter cells exhibit brownian movement
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the nuclei of stained elements?
2) What is/are the usual distinguishing color/s of the cytoplasm of stained elements?
3) What is/are the comment/s?
Given element in urinary sediment: RTE cells
1) Dark shade of blue-purple
2) Light shade of blue-purple
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the nuclei of stained elements?
2) What is/are the usual distinguishing color/s of the cytoplasm of stained elements?
3) What is/are the comment/s?
Given element in urinary sediment: Bladder tubular epithelial cells
1) Blue-purple
2) Light purple
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the nuclei of stained elements?
2) What is/are the usual distinguishing color/s of the cytoplasm of stained elements?
3) What is/are the comment/s?
Given element in urinary sediment: Squamous epithelial cells
1) Dark shade of orange-purple
2) Light purple / blue
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the inclusions and matrix of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: Hyaline casts
1) Pale pink / pale purple
2) Very uniform color; slightly darker than mucous threads
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the inclusions and matrix of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: Coarse granular inclusion casts
1) Dark purple granules in purple matrix
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the inclusions and matrix of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: Finely granular inclusion casts
1) Fine dark purple granules in pale pink / pale purple matrix
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the inclusions and matrix of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: Waxy casts
1) Pale pink / pale purple
2) Darker than hyaline casts, but of a pale even color; distinct broken ends
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the inclusions and matrix of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: Fat inclusion casts
1) Fat globules unstained in a pink matrix
2) Rare; presence is confirmed if examination under polarized light indicates double refraction
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the inclusions and matrix of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: Red cell inclusion casts
1) Pink to orange-red
2) Intact cells can be seen in matrix
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the inclusions and matrix of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: Blood (hgb) casts
1) Orange-red
2) No intact cells
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the inclusions and matrix of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: Bacteria
1) Motile: do not stain; nonmotile: stain purple
2) Motile organisms are not impaired
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the inclusions and matrix of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: Trichomonas vaginalis
1) Light blue-green
2) Motility is unimpaired in fresh sxs when recommended volumes of stain are used; immobile organisms also identifiable
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the inclusions and matrix of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: Mucus
1) Pale pink / pale blue
Answer the ff questions w/ regards to the given element in urinary sediment:
1) What is/are the usual distinguishing color/s of the inclusions and matrix of stained elements?
2) What is/are the comment/s?
Given element in urinary sediment: Background
1) Pale pink / pale blue
Is cytodiagnostic urine testing part of the routine examination of the urine sediment?
No
In cytodiagnostic urine testing, what is done to prepare permanent slides?
Cytocentrifugation
What is the aid of the preparation of permanent slides using cytocentrifugation, followed by staining w/ Papanicolaou stain?
It provides an additional method for detecting and monitoring renal disease
True or False
Cytodiagnostic urine testing is frequently performed independently of routine UA
True
Cytodiagnostic urine testing is frequently performed independently of routine UA for detection of what?
For detection of malignancies of the lower urinary tract
What is the type of sx recommended for testing in cytodiagnostic urine testing?
First morning sx
What lab performs cytodiagnostic urine testing?
Cytology lab
What are the aids of cytodiagnostic urine testing?
1) For detection of malignancies of the lower urinary tract
2) Provides more definitive information about renal tubular changes associated w/ transplant rejection
3) Provides more definitive information about renal tubular changes associated w/ infections
a. Viral
b. Fungal
c. Parasitic
4) Provides more definitive information about renal tubular changes associated w/ cellular inclusions
5) Provides more definitive information about renal tubular changes associated w/ pathologic casts
6) Provides more definitive information about renal tubular changes associated w/ inflammatory conditions
What should the UA lab do to sxs w/ unusual cellular findings?
These sxs should be referred to the pathologist for further examination
When is microscopic examination of urine best performed?
When the laboratorian is knowledgeable about:
1) Types of microscopes available
2) The primary characteristics (of the microscopes)
3) The proper use and maintenance of these microscopes
What is the most common type of microscopy performed in the UA lab?
Bright-field microscopy
What are the other types of microscopy that are useful for examining the urine sediment?
1) Phase contrast
2) Polarizing
3) Dark field
4) Fluorescence
5) Interference contrast
The type of microscopy used depends on what factors?
1) Sx type
2) Refractive index of the object
3) Ability to image unstained living cells
All microscopes are designed to what?
To magnify small objs to such a degree that the details of their structure can be analyzed
How does all microscopes magnify small objects (to such a degree that the details of their structure can be analyzed)?
Basically, they do this by employing a variety of lenses and light sources
What are the essential components that are contained by all types of microscopes?
1) Lens system
Primary components:
a. Oculars
b. Objectives
c. Coarse adjustment knob
d. Fine adjustment knob
2) Illumination system
a. Light source
b. Condenser
c. Field diaphragm
d. Iris diaphragm
3) Body
a. Base
b. Body tube
c. NosepieceWhere are the objs to be examined (via the use of microscope) placed?
These are placed on a platform (w/c is referred to as the mechanical stage)
What is the type of microscope that is primarily used in the UA lab?
Compound bright-field microscope
What are the parts of the compound bright-field microscope?
1) Two-lens system
a. First lens system (located in the objective and is adjusted to be near the sx)
b. Second lens system (the ocular lens | located in the eyepiece)
2) Light source
Where is the path of light (/ where does it pass through) in compound bright-field microscope?
It passes through the sx up to the eyepiece
Where are the oculars or eyepieces of the microscope located?
At the top of the body tube
True or False
Clinical lab microscopes are binocular
True
What is the aid of clinical lab microscopes being binocular?
It allows the examination to be performed using both eyes to provide more complete visualization
What can be done (to clinical lab microscopes) for optimal viewing conditions?
The oculars can be adjusted horizontally to adapt to differences in interpupillary distance between operators
What is the purpose of a diopter adjustment knob on the oculars?
It can be rotated to compensate for variations in vision between the operators’ eyes
The oculars are designed to what?
To further magnify the obj that has been enhanced by the objectives for viewing
Lab microscopes normally contain what?
Oculars (w/c are capable of increasing the magnification 10 times [10x])
The field of view is determined by what?
Eyepiece
The field of view w/c is determined by the eyepiece is what?
It is the diameter of the circle of view (when looking through the oculars)
The field of view varies w/ what?
It varies w/ the:
1) Field number engraved on the eyepiece
2) Magnification of the objective
True or False
The higher the magnification, the smaller the field of view will be
True
In UA microscopy, the sediment constituents are reported as what?
As the number per microscopic field (number per hpf or lpf)
Where are the objectives contained / located?
These are contained in the revolving nosepiece (w/c is located above the mechanical stage)
What is the action done to the objectives?
These are adjusted to be near the sx and perform the initial magnification of the object on the mechanical stage
What happens to the image (after performing the initial magnification of the object on the mechanical stage | after adjusting the objectives to be near the sx)?
This then passes to the oculars for further resolution
What is resolution?
1) It is the ability to visualize fine details
2) It is the ability of the lens to distinguish 2 small objs that are a sp. distance apart
When is resolving power best?
It is best when the distance between the 2 objs is small
Resolving power is dependent on what?
It is dependent on the:
1) Wavelength of light
2) Numerical aperture of the lens
True or False
The longer the wavelength of light, the greater the resolving power of the microscope will be
False, because the shorter the wavelength of light, the greater the resolving power of the microscope will be
What are the objectives (and their corresponding magnifications) that are routinely used in the clinical lab?
1) Low power, dry: 10x
2) High power, dry: 40x
3) Oil immersion: 100x
What are the objectives used for examination of urine sediment?
1) 10x
2) 40x
How to obtain / compute for the final magnification of an object?
Objective magnification x ocular magnification
What is the total magnification / final magnification if a 10x ocular and a 10x objective is used and what is this observation called?
100x (w/c is called the lpf observation)
What is the total magnification / final magnification if a 10x ocular and a 40x objective is used and what is this observation called?
400x (w/c is called the hpf observations)
What is inscribed in the objectives (in the microscope)?
Objectives are inscribed w/ the info that describes:
1) Their characteristics
2) The type of objective (plan used for bright field, ph for phase contrast)
3) Their magnification
4) Their numerical aperture
5) The microscope tube length
6) The thickness of cover-slip to be used
The numerical aperture number represents what?
It represents the:
1) Refractive index of the material between the slide and the outer lens (air / oil)
2) Angle of the light passing through the material
True or False
The higher the numerical aperture, the better the light-gathering capability of the lens will be, thus yielding greater resolving power
True
True or False
The length of the objectives attached to the nosepiece varies w/ magnification (length increases from 10x - 100x magnification), thereby changing the distance between the lens and the slide when they are rotated
True
True or False
The higher the numerical aperture, the closer the lens is to the obj
True
Most microscopes are designed to be what?
Parfocal
What is the meaning of the microscope being parfocal?
It indicates that they require only minimum adjustment when switching among objectives
What are used to control the distance between the slide and the objective?
1) Coarse-focusing knobs
2) Fine-focusing knobs
Where are the coarse and fine-focusing knobs located?
These are located on the body tube
What are the actions of the coarse knob?
1) Initial focusing
2) Moves the mechanical stage noticeably up and down (until the obj comes into view)
What is the next that is used after using coarse knob?
Fine-focusing knob
What is the action of fine-focusing knob (after using the coarse knob)?
It sharpens the image
What should only be used for adjustment when changing magnifications (when using a parfocal microscope)?
Fine knob
What provides the illumination for the modern microscope?
Light source
Where is the light source located?
In the base of the microscope
The light source (in modern microscope) is equipped w/ what?
Rheostat
What is the purpose of the rheostat (w/c is equipped in the light source of the modern microscope)?
It regulates the intensity of the light
What may also be placed on the light source (in modern microscopes)?
Filters
What is the purpose of filters (that may also be placed on the light source [on compound microscope])?
To vary the illumination and wavelengths of the emitted light
What is contained in the light source (of a compound microscope)?
A field diaphragm
What is the purpose of a field diaphragm (w/c is contained in the light source [of a compound microscope])?
It controls the diameter of the light beam reaching the slide and is adjusted for optimal illumination
Where is the condenser located?
Below the stage
What are the purposes of the condenser?
1) It focuses the light on the sx
2) It controls the light for uniform illumination
What is the normal position of the condenser?
It is almost completely up w/ the front lens of the condenser near the slide but not touching it
What is the purpose of condenser adjustment (focus) knob?
It moves the condenser up and down to focus light on the obj
Where is aperture diaphragm present?
In the condenser
What is the purpose of the aperture diaphragm in the condenser?
It controls the amt of light and the angle of light rays that pass to the sx and lens
The amt of light and the angle of light rays that pass to the sx and lens affects what?
1) Resolution
2) Contrast
3) Depth
Of the field of image
How to achieve the maximum resolution?
By adjusting the aperture diaphragm to 75% of the numerical aperture of the objective
Should the aperture diaphragm be used to reduce light intensity? Why or why not?
No, because it decreases resolution
What is used for the adjustment (whereas the aperture diaphragm should not be used to reduce light intensity because it decreases resolution)?
Microscope lamp rheostat
What are the 2 adjustments to the condenser?
1) Centering
2) Köhler illumination
*What is the purpose of centering Köhler illumination?
To provide optimal viewing of the illuminated field
When should centering and Köhler illumination be performed?
Whenever an objective is changed
What is the procedure of how to center the condenser and obtain Köhler illumination?
1) Place a slide on the stage and focus the obj using the low-power objective w/ the condenser raised
2) Close the field diaphragm
3) Lower the condenser until the edges of the field diaphragm are sharply focused
4) Center the image of the field diaphragm w/ the condenser centering screws
5) Open the field diaphragm until its image is at the edge of the field
6) Remove an eyepiece and look down through the eyepiece tube
7) Adjust the aperture diaphragm until approx 75% of the field is visible
8) Replace the eyepiece
What are parts (of the microscope) that should be used for additional focusing of the obj?/
1) Adjustment knobs
2) Rheostat (on the light source)
How to ensure good optical performance (of the microscope)?
Via doing routine preventive maintenance procedures on the microscope
What should be done to the microscope when not in use and what is its purpose?
It should always be covered when not in use to protect it from dust
What should be done if any optical surface (of the microscope) becomes coated w/ dust?
It should be carefully removed w/ a camel-hair brush
What should be done to optical surfaces (of the microscope)?
These should be cleaned w/ lens paper
What should be done to any contaminated lens (in the microscope)?
These should be cleaned w/ a commercial lens cleaner
What are the actions that must be done to the oil immersion lens (of the microscope) after each use?
1) It must be wiped free of oil
2) It must be cleaned
What is the effect of fingerprints and oil smears?
These impair the sharpness of an image
What is recommended to be done (/ how often should it be done)? to the microscope?
The microscope should have an annual professional cleaning
True or False
Light sources (of the microscope) are replaced as necessary
True
What is the fxn of the given UA microscopic technique?
Given UA microscopic technique: Bright-field microscopy
Used for routine UA
What is the fxn of the given UA microscopic technique?
Given UA microscopic technique: Phase-contrast microscopy
Enhances visualization of elements w/ low refractive indices such as:
1) Hyaline casts
2) Mixed cellular casts
3) Mucous threads
4) Trichomonas
What is the fxn of the given UA microscopic technique?
Given UA microscopic technique: Polarizing microscopy
Aids in identification of chole in oval fat bodies, fatty casts, and crystals
What is the fxn of the given UA microscopic technique?
Given UA microscopic technique: Dark-field microscopy
Aids in identification of Treponema pallidum
What is the fxn of the given UA microscopic technique?
Given UA microscopic technique: Fluorescence microscopy
Allows visualization of naturally fluorescent microorganisms or those stained by a fluorescent dye including labeled Ags and Abs
What is the fxn of the given UA microscopic technique?
Given UA microscopic technique: Interference-contrast
Produces a three-dimensional microscopy image and layer-by-layer imaging of a sx
What are the parts of the binocular microscope?
1) Interpupillary distance control
2) Ocular
3) Body
4) Condenser focus knob
5) Course adjustment knob
6) Fine adjustment knob
7) Mechanical stage adjustment knobs
8) Nosepiece
9) Objective
10) Condenser aperture diaphragm control ring
11) Condenser
12) Centering screw
13) Field diaphragm control ring
14) Rheostat
What are the things that should be done to take care of the microscope?
1) Carry microscope w/ 2 hands (supporting the base w/ 1 hand)
2) Always hold the microscope in a vertical position
3) Clean optical surfaces only w/ a good quality lens tissue and commercial lens cleaner
4) Do not use the 10x and 40x objectives w/ oil
5) Clean the oil immersion lens after use
6) Always remove slides w/ the low-power objective raised
7) Store the microscope w/ the low-power objective in position and the stage centered
What are the different types of microscopy?
1) Bright-Field microscopy
2) Phase-contrast microscopy
3) Polarizing microscopy
4) Interference-contrast microscopy
5) Dark-field microscopy
6) Fluorescence microscopy
What is the principle of bright-field microscopy?
Objs appear dark against a light bg
What type of microscopy is most frequently used in the clinical lab?
Bright-field microscopy
What does bright-field microscopy (/ technique) employ?
It is a basic microscope w/ a light source (w/c emits light in the visible wavelength range)
Can the use of bright-field microscopy present problems in the the examination of urine sediments? If yes, when? If no, why?
Yes, when the amt of light reaching the sx is not properly controlled
What is the effect of the problem that can arise (in terms of examination of the urine sediments) if bright-field microscopy is used?
Sediment constituents w/ a low refractive index will be overlooked when subjected to light of high intensity
Due to the effect that can arise (in terms of examination of the urine sediments) if bright-field microscopy is used, what is the resolution that must be done to assess this problem?
Sediments must be examined using decreased light
How to properly control the light (in connection to the resolution to the problem that can arise in terms of examination of urine sediments [if bright-field microscopy is used])?
Via adjusting the rheostat on the light source, not by lowering the condenser
What is the aid of staining of the sediment (in bright-field microscopy | in terms of examination of urine sediments)?
Staining of the sediment also increases the visualization of the urine sediments / elements
What is phase difference (/ what is the principle of phase difference)?
As light rays pass through an obj, they are slowed in comparison to the rays passing through air (media), thereby decreasing the intensity of the light and producing contrast
What are the factors that affect phase difference?
1) Thickness of the obj
2) Refractive index
3) Other light-absorbance properties
When is the best contrast obtained (in phase-contrast microscopy) and what type of microscopy provides this contrast?
It is obtained when the light that does not pass through the sx is shifted 1 quarter of a wavelength and compared w/ the phase difference of the sx
This is provided by phase-contrast microscopy
How is phase-contrast microscopy accomplished?
It is accomplished by adaptation of a bright-field microscope w/ a phase contrast objective lens and a matching condenser
Bright-field microscope (adapted) + phase contrast objective lens + matching condenser
What are placed in the condenser and the objective (in phase-contrast microscopy)?
Two phase rings (that appear as “targets”)
Where is one phase ring placed (in phase-contrast microscopy)?
In the condenser or below it
What is the action of 1 phase ring (w/c is placed in the condenser or below it)?
It permits light to only pass through the central clear circular area
Where is a second phase-shifting ring (w/ a central circular area that retards light by 1 quarter wavelength) placed (in phase-contrast microscopy)?
In the objective
True or False
Phase rings must match (in phase-contrast microscopy)
True
Since phase rings must match (in phase-contrast microscopy), what should be done?
It is impt to check that the objective and condenser mode are the same
True or False
The diameter of the rings varies w/ the magnification (in phase-contrast microscopy)
True
When is the image (in phase-contrast microscopy) have the best contrast?
When the bg is darkest
What must be done to have maximum contrast (in phase-contrast microscopy)?
Phase-contrast rings must be adjusted
True or False
The 2 rings are adjusted to make them concentric (in phase-contrast microscopy)
True
What is the method of adjustment steps (of the phase-contrast rings | to have a maximum contrast | in phase-contrast microscopy)?
1) Focus the microscope in bright-field w/ a sx slide
2) Select a low-power phase condenser ring
3) Select the corresponding ring objective
4) Remove an ocular, insert the adjustment telescope, and look through the telescope
5) Observe the dark and light rings (annuli)
6) W/ the adjusting screw on the telescope, center the light annulus (condenser) over the dark annulus (objective)
7) Replace the ocular
*What is the principle of phase-contrast microscopy?
Light passes to the sx through the clear circle in the phase ring in the condenser, forming a halo of light around the sx. The diffracted light then enters the central circle of the phase-shifting ring, and all other light is moved 1 quarter of a wavelength out of phase. The variations of contrast in the sx image due to the various refractive indexes in the obj are observed as the light rays merge together, enhancing visualization and detail
What is the advantage of using phase-contrast microscopy?
It is particularly advantageous for identifying:
1) Low refractive hyaline casts
2) Or mixed cellular casts
3) Mucous threads
The use of polarized light (in polarizing microscopy) aids in the identification of what components / urine sediments?
1) Crystals
2) Lipids
What are the characteristics of crystals and lipids?
1) Both substances have the ability to rotate the path of the unidirectional polarized light beam to produce:
a. Characteristic colors in crystals
b. Maltese cross formation in lipids
2) These are birefringent
What is birefringent?
It is a property indicating that the element can refract light in 2 dimensions at 90 degrees to each other
What produces light rays of many different waves (in polarizing microscopy)?
The halogen quartz lamp (in the microscope)
What is the characteristic of each wave (since the light rays [produced by the halogen quartz lamp in the microscope] have many different waves)?
Each has a distinct direction and a vibration perpendicular to its direction
True or False
In polarizing microscopy, normal or unpolarized light vibrates in equal intensity in all directions
True
What is the characteristic of polarized light (in polarizing microscopy)?
It vibrates in the same plane / direction
What happens as the light passes through a birefringent substance (in polarizing microscopy)?
It splits into 2 beams (1 beam rotated 90 degrees to the other)
Provide an ex of isotropic substances
Blood cells
What is the characteristic of blood cells?
*They do not have the refractive property (/ birefringence) and the light passes through unchanged
What is the principle of positive birefringence?
A substance that rotates the plane of polarized light 90 degrees in a clockwise direction
What is the principle of negative birefringence?
A substance that rotates the plane in a counterclockwise direction
How to obtain the polarized light (in polarizing microscopy)?
By using 2 polarizing filters
What is the principle of action of the 2 polarizing filters (in polarizing microscopy)?
The light emerging from 1 filter vibrates in 1 plane, and a 2nd filter placed at a 90-degree angle blocks all incoming light, except that rotated by the birefringent substance
True or False
The 2 polarizing filters are in opposite directions called a “crossed configuration” (in polarizing microscopy)
True
True or False
Between cross-polarizing filters, birefringent crystals are not visible in characteristic patterns
False, because between cross-polarizing filters, birefringent crystals are visible in characteristic patterns
True or False
Bright-field microscopes can be adapted for polarizing microscopy
True
True or False
2 polarizing filters must be installed in a cross configuration (in polarizing microscopy)
True
What is the 1st filter (w/c must be installed in a cross configuration | in polarizing microscopy)?
The polarizing filter
Where is the polarizing filter placed (in polarizing microscopy)?
In the condenser filter holder
What is the 2nd filter (w/c must be installed in a cross configuration | in polarizing microscopy)?
The analyzer
Where is the analyzer placed (in polarizing microscopy)?
In the head between the objectives and the ocular
What is the action done to the polarizing filter and what is its purpose?
It is rotated to allow light vibrating in 1 direction only to reach the obj
After rotating the polarizing filter, what are the things that will happen if the obj does not have birefringent properties (in polarizing microscopy)?
1) No light will reach the analyzer filter
2) The obj will appear black
*After rotating the polarizing filter, what will happen (in polarizing microscopy)?
Refracted rays from a birefringent obj will reach the analyzer, causing the obj to appear white or colored against the black bg
What is the additional filter that can be added to the microscope (in polarizing microscopy)?
A red compensated polarizing filter
What is the action of the red compensating polarizing filter (in polarizing microscopy)?
It divides the light entering the microscope into slow and fast vibrations
What is the aid of aligning the crystals w/ the slow vibration (via the use of the red compensated polarizing filter | in polarizing microscopy)?
Crystals can be more easily identified
What is the color that crystals produce (if they are aligned w/ the slow vibration [via the use of the red compensated polarizing filter] | in polarizing microscopy)?
Blue / yellow
What are the uses of polarizing microscopy in UA?
1) To confirm the identification of:
a. Fat droplets
b. Oval fat bodies
c. Fatty casts
2) To distinguish birefringent uric acid crystals from cystine crystals (by their polarizing characteristics)
3) To distinguish monohydrate calcium oxalate crystals from nonpolarizing RBCs (by their polarizing characteristics)
4) To distinguish calcium phosphate crystals from nonpolarizing bacteria (by their polarizing characteristics)
What is the characteristic of fat droplets, oval fat bodies, and fatty casts (in UA)?
These produce a characteristic Maltese cross pattern
What is the principle of interference-contrast microscopy?
It 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 sx. The light interference produced by the varied depths of the sx is compared, and a three-dimensional image is visualized
What is the advantage of interference-contrast microscopy?
An obj appears bright against a dark bg but w/out the diffraction halo associated w/ phase-contrast microscopy
What are required to perform interference-contrast microscopy?
More extensive modifications to the bright-field microscope
True or False
Since more extensive modifications to the bright-field microscope are required to perform interference-contrast microscopy, hence, interference-contrast microscopy is not routinely used in the UA lab
True
What are the 2 types of interference-contrast microscopy that are available?
1) Modulation contrast (Hoffman)
2) Differential-interference contrast (Nomarski)
Can bright-field microscopes be adapted for both methods (of both types of interference-contrast microscopy)?
Yes
What are the components present in the modulation-contrast microscope?
1) A split aperture
2) A polarizer
3) An amplitude filter
Where is the split aperture placed (in the modulation-contrast microscope | in interference-contrast microscopy)?
Below the condenser
Where is the polarizer placed (in the modulation-contrast microscope | in interference-contrast microscopy)?
Below the split aperture
Where is the amplitude filter placed (in the modulation-contrast microscope | in interference-contrast microscopy)?
In back of each objective
True or False
The modulator (in interference-contrast microscopy) has 4 zones of light transmission
False, because the modulator (in interference-contrast microscopy) has 3 zones of light transmission
What are the 3 zones of light transmission (in interference-contrast microscopy)?
1) A dark zone
2) A gray zone
3) A clear zone
The dark zone transmits how many percentage of light?
1%
The gray zone transmits how many percentage of light?
15%
The clear zone transmits how many percentage of light?
100%
What is the action of polarized light rays (in phase-contrast microscopy)?
It pass through a split aperture to the various areas of the sx and to the modulator where they are converted into the variations of light intensity to produce a three-dimensional image
True or False
The differential interference-contrast microscope uses prisms
True
What is placed between the light source and condenser (in interference-contrast microscopy)?
A polarizing filter to output plane-polarized light
What is the action of two-layered Nomarski-modified Wollaston prism (in interference-contrast microscopy)?
It separates the individual rays of light into ray pairs is required
Where is the lower Wollaston prism built into the microscope (in interference-contrast microscopy)?
Into the condenser of the microscope
Where is the upper prism placed and what is its action (in interference-contrast microscopy)?
Between the objective and the eyepiece and recombines the rays
True or False
Above the top Wollaston prism, another polarizing filter is placed that causes wave interference to occur and produce the three-dimensional image (in interference-contrast microscopy)
True
*True or False
These two types of microscopy provide layer-by-layer imaging of a sx and enhanced detail for sxs w/ either a low or high refractive index
True
What is dark-field microscopy?
It is a technique used in the clinical lab to enhance visualization of sxs that cannot be easily viewed w/ a bright-field microscope
At what type of sxs is dark-field microscopy often used?
Unstained sxs
What is the particular organism (to be identified) where dark-field microscopy is often used?
Spirochete Treponema pallidum
Is a bright-field microscope easily adapted for dark-field microscopy? If yes, how? If no, why?
Yes, by replacing the condenser w/ a dark-field condenser that contains an opaque disk
What is the action of the disk (specifically the opaque disk that is contained in a dark-field condenser)?
It blocks the light from directly entering the objective, and the field of view is black
What is the principle of dark-field microscopy?
As the light rays pass through the sx at oblique angles, the light scatters, diffracts, or reflects off the sx and is captured by the objective lens. The sx appears light against the black bg or dark-field
