1030 Unit 3 - Microscopic examination
54 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which formed elements are typically identified during a microscopic examination of urinary sediment? Select all that apply.

  • Hyaline casts (correct)
  • Carbon dioxide
  • Parasites (correct)
  • Renal stones

    • What factor does NOT directly affect the standardization of microscopic analysis in urinary sediment?

  • Volume of sediment examined
  • Methods of sediment preparation
  • Methods used for visualization
  • Time of day the specimen is collected (correct)

    • In what cases does the CLSI recommend that physicians request microscopic screenings?

  • Pregnant women (correct)
  • Routine screening for all patients
  • Examine only preserved specimens
  • Focus only on physical characteristics

    • What type of specimen should have the least epithelial cell contamination?

    <p>A midstream clean-catch</p> Signup and view all the answers

    What happens to red blood cells and white blood cells in dilute, alkaline urine?

    <p>They disintegrate</p> Signup and view all the answers

    Which of the following is a key factor in identifying abnormalities during macroscopic screening?

    <p>Color and clarity</p> Signup and view all the answers

    What is the effect of refrigeration on urine specimens?

    <p>It precipitates crystals</p> Signup and view all the answers

    Why is it important to thoroughly mix a urine specimen before decanting it to the centrifuge tube?

    <p>To ensure even distribution of formed elements</p> Signup and view all the answers

    What is the primary indicator of lipiduria in urine samples?

    <p>Presence of oval fat bodies</p> Signup and view all the answers

    Which of the following structures would be reported as a sign of yeast infection?

    <p>Single refractile oval structures</p> Signup and view all the answers

    What is the most common type of bacteria associated with urinary tract infections?

    <p>Enterobacteriaceae</p> Signup and view all the answers

    What might the presence of Trichomonas vaginalis indicate in a urine specimen?

    <p>Parasitic infection</p> Signup and view all the answers

    How should the presence of yeast be reported in a urine sample?

    <p>Few, moderate, many</p> Signup and view all the answers

    How might you confirm the presence of fat in urine (lipiduria)?

    <p>Stain with Crystal Violet or Giemsa</p> Signup and view all the answers

    Which condition is NOT typically associated with lipiduria?

    <p>Viral infection</p> Signup and view all the answers

    What is the typical appearance of bacteria in urine samples?

    <p>Spherical and rod-shaped</p> Signup and view all the answers

    What type of casts are primarily associated with tubular damage and pyelonephritis?

    <p>Epithelial cell casts</p> Signup and view all the answers

    Which method is useful for distinguishing the cellular composition of casts?

    <p>Sediment stains</p> Signup and view all the answers

    In which condition are fatty casts primarily observed? Select all that apply.

    <p>Nephrotic syndrome</p> Signup and view all the answers

    What primarily gives granular casts their appearance?

    <p>RTE lysosomes</p> Signup and view all the answers

    What do RBC casts indicate regarding kidney health?

    <p>Glomerular damage</p> Signup and view all the answers

    What describes the structure of spermatozoa?

    <p>Oval, tapered heads and long tails</p> Signup and view all the answers

    What appearance do oval fat bodies typically exhibit?

    <p>Highly refractile and may stain orange</p> Signup and view all the answers

    Which of the following statements about urine and spermatozoa is true?

    <p>Spermatozoa are immobile in urine due to its toxicity.</p> Signup and view all the answers

    During microscopic examination, what should be looked for when confirming tubular necrosis?

    <p>RTE cells</p> Signup and view all the answers

    The presence of which type of cast is indicative of infection in the kidneys?

    <p>WBC and bacterial casts</p> Signup and view all the answers

    Which type of cast is primarily associated with infection and inflammation of the nephron?

    <p>WBC casts</p> Signup and view all the answers

    What is the primary significance of mucus in urine specimens?

    <p>Confuses with casts and has no clinical significance.</p> Signup and view all the answers

    What is a notable characteristic of WBC casts?

    <p>Neutrophils with a lobed nucleus</p> Signup and view all the answers

    Which of the following cellular casts indicates damage to renal tubular cells?

    <p>Epithelial cell casts</p> Signup and view all the answers

    Where are casts formed in the urinary system?

    <p>In the distal convoluted tubule and collecting duct.</p> Signup and view all the answers

    What is a major constituent of cast formation in urine?

    <p>Uromodulin protein.</p> Signup and view all the answers

    What is typically seen in pyelonephritis concerning casts?

    <p>WBC casts with bacteria</p> Signup and view all the answers

    What is essential for detecting casts under microscopic examination? Select all that apply.

    <p>Low light conditions.</p> Signup and view all the answers

    How does hemoglobin degradation affect cast appearance?

    <p>Produces dirty brown casts</p> Signup and view all the answers

    What is required for confirming the presence of bacterial casts?

    <p>Gram stain</p> Signup and view all the answers

    What characteristic of mucus can lead to confusion during microscopic analysis?

    <p>Its threadlike appearance.</p> Signup and view all the answers

    In acute interstitial nephritis, what distinguishes it from pyelonephritis?

    <p>Absence of bacteria despite WBC casts</p> Signup and view all the answers

    What characterizes granular casts in urine samples?

    <p>Composed of disintegrating granules</p> Signup and view all the answers

    Which of the following describes waxy casts?

    <p>Brittle with jagged ends and notches</p> Signup and view all the answers

    Broad casts are commonly associated with which condition?

    <p>Renal failure</p> Signup and view all the answers

    What's the difference between normal and abnormal urinary crystals?

    <p>Abnormal crystals may indicate serious health conditions</p> Signup and view all the answers

    What factor influences crystal formation in urine?

    <p>Urine pH and solute concentration</p> Signup and view all the answers

    How are broad casts formed in urine?

    <p>During destruction and widening of the distal convoluted tubules</p> Signup and view all the answers

    In what type of urine specimen are many crystals commonly found?

    <p>Refrigerated specimens</p> Signup and view all the answers

    What staining characteristic is seen with waxy casts?

    <p>Homogeneous dark pink stain</p> Signup and view all the answers

    What are cholesterol crystals characterized by?

    <p>Rectangular plates with notched corners</p> Signup and view all the answers

    What might be indicated by the presence of bilirubin crystals?

    <p>Viral hepatitis with tubular damage</p> Signup and view all the answers

    Which type of crystal is commonly associated with inherited amino acid disorders which cause liver disease?

    <p>Leucine crystals</p> Signup and view all the answers

    What is a possible consequence of dehydration in relation to sulfonamide crystals?

    <p>Tubular damage</p> Signup and view all the answers

    How can one differentiate radiographic dye crystals from cholesterol crystals?

    <p>Patient history and UA comparison</p> Signup and view all the answers

    What shape do ampicillin crystals typically take?

    <p>Colorless needles</p> Signup and view all the answers

    What characteristic identifies tyrosine crystals?

    <p>Fine colorless or yellow needles in clumps</p> Signup and view all the answers

    What is the typical appearance of sulfonamide crystals?

    <p>Needles and whetstones, colorless to yellow-brown</p> Signup and view all the answers

    Study Notes

    Microscopic Exam - Part 1

    • PowerPoints are general overviews for taking notes on video lectures only.
    • PowerPoints do not detail information needed for the unit exam.
    • Students are responsible for reading the textbook for unit exam details.
    • Unit Objectives are study guides, not the PowerPoint.
    • Test questions are based on Unit Objectives found in the textbook.

    Introduction

    • Microscopic examination of urinary sediment identifies insoluble substances (formed elements).
    • Formed elements include red blood cells (RBCs), white blood cells (WBCs), epithelial cells, casts, bacteria, yeast, parasites, mucus, spermatozoa, crystals, and artifacts.

    Introduction (continued)

    • Microscope analysis varies due to procedural differences.
    • Variations include sediment preparation methods, sediment volume examined, visualization methods, and reporting of results.

    Macroscopic Screening

    • Microscopic analysis is based on physical and chemical results (color, clarity, blood, protein, nitrite, leukocyte esterase, glucose).
    • Factors to consider for special populations (pregnant, pediatric, geriatric, diabetic, immunocompromised, and renal patients) are per Clinical and Laboratory Standards Institute (CLSI) recommendations.
    • Abnormal physical or chemical results require further review.

    Specimen Preparation

    • Examine specimens when fresh or preserved.
    • RBCs, WBCs, and casts disintegrate in dilute, alkaline urine.
    • Refrigeration precipitates crystals.
    • Use midstream clean-catch specimens for less contamination.
    • Thoroughly mix specimens before decanting.

    Specimen Volume

    • Centrifuge 10-15 mL urine (reagent strips fit into 12 mL).
    • Document volumes less than 12 mL.
    • Some labs correct for volume.

    Centrifugation

    • Standardize speed and time for centrifugation.
    • 5 minutes at relative centrifugal force (RCF) of 400 is ideal.
    • Adjust for variations in centrifuge head diameter.
    • RCF calculation: RCF = 1.118 x 10⁻⁵ × radius in centimeters × RPM².
    • Do not brake the centrifuge.
    • Cap all specimens.

    Sediment Preparation

    • Examined sediment volume is 0.5-1.0 mL.
    • Calculate urine concentration factor (volume of urine centrifuged divided by sediment volume).
    • Aspirate urine rather than pour off.
    • Gently agitate sediment to re-suspend.
    • Avoid vigorous agitation.

    Volume of Sediment Examined

    • Maintain consistency in sediment volume.
    • Commercial systems control volume.
    • Glass slide methods (20 μL, 22 x 22 mm cover slip), ensuring no overflow.
    • Heavier elements (e.g., casts) flow outside of the cover slip.

    Commercial Systems

    • Commercial slide systems improve microscopic analysis.
    • CLSI recommends using them with standardized methodology.
    • Various systems are available.
    • Capped, calibrated centrifuge tubes, decanting pipettes control sediment volume.
    • Control sediment amount; produce consistent monolayer for examination; use calibrated grids for quantitative analysis.

    Examination of Sediment

    • Consistent observation technique is necessary.
    • Minimum of 10 low (10x) and 10 high (40x) fields.
    • Low power: assess casts and general composition.
    • Scan edges for casts (glass slide method).
    • High power: identify types (initially lower light intensity, adjust focus on epithelial cells, keep the focus plane consistent so artifacts are not included). Use fine adjustment continuously for best view.

    Reporting the Examination

    • Maintain consistent results within the laboratory.
    • Report casts (average per Ipf) and RBCs/WBCs (average per hpf).
    • Use semiquantitative terms ("few," "moderate," "many") for epithelial cells, crystals, etcetera (followed by /lpf or /hpf).

    Reporting the Microscopic Examination

    • Convert elements per Ipf or hpf to elements/mL.
    • Calculate the area of the field of view (using the formula πr² = area where the diameter is supplied, convert from mm to meters, and then calculate to get mm² ).
    • Calculate maximum number of fields of view in a specific area. (A standardized cover slip size is used for calculations).
    • Calculate elements per milliliter.

    Reporting the Microscopic Examination (continued)

    • Calculate the number of fields per milliliter of urine using the concentration factor and the volume of sediment examined from page 8.
    • Calculate elements per milliliter of urine.

    Correlating Results

    • Use a table correlating microscopic elements with physical or chemical properties, and exceptions.

    Sediment Examination Techniques

    • Observe sediment appearance for various stages of development/degeneration.
    • Note distortion of cells and crystals due to chemical content.
    • Check for inclusions in cells and casts.
    • Evaluate for contamination by artifacts.

    Sediment Stains

    • Bright-field microscopy visibility improves with staining for cellular structures (nuclei, cytoplasm, and inclusions).
    • Staining is done on sediment.

    Supravital Stains

    • Sternheimer-Malbin stain (crystal violet/safranin O) is a common stain.
    • Increases refractive index of sediments.
    • Useful for differentiating WBCs from renal tubular epithelial cells. 0.5% toluidine blue enhances nuclear detail to differentiate WBC from renal tubular epithelial cells.

    Acetic Acid

    • Enhancing WBCs and epithelial cells is achieved.
    • RBCs are lysed.

    Lipid Stains

    • Lipid results appear as free fat droplets and lipid-containing cells/casts.
    • Oil Red O and Sudan III stains are used.
    • Triglycerides/neutral fats stain orange-red.
    • Cholesterol does not stain.

    Gram Stain

    • Differentiate between gram-positive and -negative bacteria (e.g., bacterial casts).

    Hansel Stain

    • Primarily use for neutrophils.
    • Used to determine microbial infection.
    • Determine eosinophils.

    Prussian Blue Stain

    • Used for hemoglobinuria analysis.
    • Hemosiderin granules are colored blue.

    Cytodiagnostic Urine Testing

    • Cytodiagnostic testing is used for identifying and monitoring renal disease/malignancies.
    • Papanicolaou or hematoxylin/eosin (H&E) stain.

    Microscopy

    • Bright-field microscopy is most common.
    • Dark-field, phase contrast, polarizing, fluorescence, and interference contrast techniques are also available.

    The Microscope

    • Compound bright-field microscopes for microscopy: two-lens system, coarse/fine adjustment knobs, illumination system (light source, condenser, and diaphragm); base, body tube, nosepiece, and mechanical stage comprise the microscope body.

    The Microscope (continued)

    • Binocular 10x microscopes: adjusts for interpupillary distance and field of view determined by the diameter of the ocular; objective magnification × ocular magnification = total magnification of samples.

    The Microscope (continued)

    • Objective characteristics (type, magnification, numerical aperture, microscope tube length, thickness of the cover slip). Adjustments are made for lens/slide distance and adjustments upon swapping objectives.

    The Microscope (continued)

    • Distance between slide and objective is controlled by coarse/fine knobs (initial focus using coarse focus and sharpen image/refine focus using fine focus). Magnification is adjusted when necessary.

    The Microscope (continued)

    • Base, equipped with rheostat for intensity control; filters adjust illumination wavelength; diaphragm controls light beam diameter; condenser focuses light; and all have adjustments for optimal lighting.

    Köhler Illumination

    • Optimal viewing of the illuminated field using Köhler illumination, particularly for microscopic specimens.

    The Microscope (continued)

    • Cover microscope when not in use.
    • Use lens paper for cleaning optical surfaces.
    • Annual professional cleaning and replacement of light sources are recommended.

    Types of Microscopy

    • Bright-field microscopy is the most common, but appropriate light adjustment is needed for sediment analysis. Staining further enhances visualization.
    • Adjust the light source to control the amount of light illuminating the specimen for visibility and prevent issues.

    Phase-Contrast Microscopy

    • Achieved by adapting bright-field microscopes (with a phase contrast objective lens and condenser) that adjust phase differences caused by variations in thickness.
    • Two phase rings (targets) are placed in the condenser/objective.
    • Rings must match for optimal contrast.

    Polarizing Microscopy

    • Detect crystals and lipids.
    • Halogen quartz lamp light produces normal/unpolarized light that vibrates in equal intensity and in the same plane or direction.
    • Light becomes polarized with two polarizing filters.
    • Crossed configuration: filters in opposite directions.
    • First filter = polarizing filter.
    • Second filter = analyzer.
    • Filter placement (crossed configuration) is required for polarization.
    • Red compensated polarizing filter can be added for enhanced visibility.
    • Crystals (blue/yellow) are easily identified.

    Polarizing Microscopy (continued)

    • Confirm identification of lipid droplets, oval fat bodies, and fatty casts, crystals.
    • Distinguish birefringent from nonbirefringent materials.
    • Identify calcium phosphate crystals vs. non-polarizing bacteria; distinguish between birefringent and nonbirefringent types.

    Interference-Contrast Microscopy

    • Three-dimensional image with fine structural detail visualized against a dark background without a diffraction halo.
    • Modulation contrast, differential interference-contrast (DIC) options are available. Not a routine urinalysis lab tool.

    Modulation-Contrast Microscopy

    • Three modifications are made for specimen visualization.
    • A split aperture is placed below the condenser; a polarizer is placed below the split aperture, and an amplitude filter (modulator) is placed behind each objective.
    • Different zones filter different levels of light.

    Differential Interference-Contrast Microscopy

    • Using birefringent crystal prisms to obtain intensity difference in specimen.
    • Converts bright-field microscope to differential interference-contrast microscopy.
    • Polarizing filter for polarized light output, condenser with modified Wollaston prisms for the objectives, Wollaston prism in the path between the objective and eyepiece, and a polarizing filter behind the Wollaston prism.

    Dark-Field Microscopy

    • Used to enhance visualization of specimens that are difficult to see using bright-field microscopy, such as Treponema pallidum, unstained specimens.
    • Using an opaque disk in the condenser in place of the normal condenser.
    • Specimen appears light against the black background.

    Fluorescence Microscopy

    • Visualizes naturally fluorescent substances or substances stained with fluorescent dyes.
    • Detect bacteria and viruses in cells/tissues via immunofluorescence.
    • Special filters select excitation and emission wavelengths to see the substance.
    • Powerful light sources are needed.

    Urine Sediment Constituents

    • Urine sediment may contain a variety of formed elements.
    • Many urines show only a few epithelial cells or a mucous strand.
    • Actual normal values are not clearly defined.
    • Values are commonly listed as:
    • 0 to 2-3 epithelial cells per high-power field (hpf)
    • 0 to 5-8 WBCs per hpf
    • 0 to 2 hyaline casts per hpf

    RBCs

    • Identification difficulties: Yeast (look for buds), Oil droplets (refractility), Air bubbles (refractility and possible different plane), Starch (refractile, polarizes), and Reagent strip correlation.
    • Smooth, nonnucleated, biconcave disks (~7 μm)
    • Crenated RBCs in hypersthenuric urine
    • "Ghost cells" in hyposthenuric urine
    • Note the characteristics to aid in diagnosis.
    • Dysmorphic RBCs suggest glomerular bleeding or strenuous exercise
    • Acanthocytic with multiple protrusions or hypochromic blebs may also contribute to diagnosis
    • Clinical significance of RBCs is related to damage to glomerular membrane or vascular injury to the genitourinary tract. Number of cells correlates with extent of damage.

    WBCs

    • Normal neutrophil count is predominant, measured using a 12 μm size reference.
    • Identify using high power.
    • Urine specimen assessment is essential, including assessing for glitter/hypotonic urine (glitter cells).
    • Brownian movement will be observed.
    • Stained light blue.
    • Nonpathological.

    WBCs (continued)

    • Identify eosinophils using a Hansel stain.
    • Identify using a Hansel stain.

    • 1% eosinophils are considered significant.

    • Concentrate sediment prior to staining.

    WBCs (continued)

    • Mononuclear cells (lymphocytes, monocytes, macrophages, or histiocytes) are rare.
    • Differentiate these cells from renal tubular epithelial cells.
    • Determine staining to aid in identification in early transplant rejection.
    • Normal WBC count is <5 per hpf, with higher counts observed in some other subjects (e.g., female).
    • Increased WBCs may occur from the ingress through glomeruli, trauma, or amoeboid migration.
    • Increased WBCs may represent infections (cystitis, pyelonephritis, prostatitis, urethritis)
    • Conditions such as glomerulonephritis, lupus erythematosus, interstitial nephritis, or tumors could also contribute to the results.
    • Bacterial presence should be reported.

    Epithelial Cells

    • Three types: Squamous, transitional, and renal tubular epithelial cells.
    • Classification criteria: Structures observed, locations found.
    • Squamous cells: vagina, female/male urethra.
    • Transitional cells: bladder, renal pelvis, calyces, ureters, upper male urethra.
    • Renal Tubular epithelial (RTE): renal tubules.

    Squamous Epithelial Cells

    • Largest cell in urine.
    • Good for microscope focusing, rare, few, moderate, or numerous per Ipf (or hpf) are used to describe the number.
    • The location of the specimen collection (midstream clean-catch) is important as contamination can complicate analysis by introducing additional contaminating cells.
    • Normal sloughing is observed.

    Squamous Epithelial Cells (continued)

    • Characteristics of squamous cells with pathologic significance (clue cells)
    • Gardnerella vaginalis (vaginal infection)
    • Coccobacillus covers most of the cell & extends over the edges.
    • More common in vaginal wet specimens in urine assessments.

    Transitional Epithelial Cells (Urothelial Cells)

    • Spherical, polyhedral, or caudate cell shape.
    • Centrally located nucleus.
    • Reported: rate, few, moderate, many, or as syncytia (clumps).
    • Significance: Catheterization = not clinically significant; Malignancy = referral to pathologist.

    Renal Tubular Epithelial Cells

    • Size and shape vary with the renal tubular area (e.g. columnar, round, oval, cuboidal).
    • Renal Fragmentation: three or more cuboidal cells.
    • Identify the location (PCT, DCT, or collecting duct) by viewing the size/shape and the cells’ localization.

    Renal Tubular Epithelial Cells-PCT Cells

    • Larger than other RTEs.
    • Shaped as columnar, convoluted, or rectangular.
    • May resemble casts.
    • Coarse granular cytoplasm.
    • Examine for the nucleus’s presence.
    • Identify these cells.

    Renal Tubular Epithelial Cells-DCT Cells

    • Smaller round or oval shape than PCT cells.
    • May be confused with WBCs or transitional cells.
    • Observe the eccentric nucleus that aids in differentiation.
    • Differentiate from spherical transitional cells.

    Renal Tubular Epithelial Cells- Collecting Duct RTEs

    Shape is consistently cuboidal, never round, and has an eccentric nucleus.

    • At least one straight edge is visible.
    • Presence of three or more cells in a clump indicates renal fragment; often present in large sheets.
    • PCT and DCT cells are absent in clumps.
    • Clinical significance: RTE cells indicate tubular necrosis (fragments indicate severe destruction); heavy metals, drug toxicity, and other causes could be indicated by the presence of RTE cells, etc.

    Postamble

    • Read the textbook for details related to the unit objectives carefully.
    • Use the Unit Objectives as a study guide.
    • All test questions come from textbook material, correlating them to the Unit Objectives.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Microscopic Exam - Part 1 PDF
    Microscopic Exam – Part 2 PDF

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser