Urinalysis Week 2 emma version

State the purpose of the microscopic examination of urine.

State the purpose of the microscopic examination of urine.

The identification of formed elements

State an advantage and a disadvantage of performing urine microscopics based on macroscopic screening.

Advantage: Low cost
Disadvantage: Lack of standardization

List the seven chemical parameters commonly used as markers in macroscopic screening.

Blood
Protein
Nitrite
Leukocyte Esterase
Glucose

List the three CLSI recommendations for urine macroscopic screening.

Requested by Physician
Lab-specified patient population
Any abnormal physical or chemical results

What is an important step in specimen preparation to ensure an adequate urine sediment?

thoroughly mix patient specimen

Why is 10-12 ml indicated for a urine volume to perform an accurate urine microscopic?

to obtain an appropriate amount of sediment (1ml)

Why is the centrifugation speed or centrifugal force (RCF) important in standardization?

optimal amount of sediment without damaging elements

What is the recommended RCF and time of centrifugation?

400 RCF for 5 mins

Why is RCF a more accurate way to determine optimum speed of centrifuge?

It accounts for the differences in diameter of centrifuge tubes

What is the desired ratio of urine volume to sediment?

1 part sediment per 12 parts urine

Why should the amount of supernatant poured off be controlled?

to prevent accidental loss of sediment

Why would it be important to control the amount of sediment examined?

to obtain an accurate normal range

Discuss the advantages of using commercial system slides for sediment examination.

to control the amount of sediment

What magnifications should be used for sediment examination? What is the purpose of each magnification?

10x: Casts, general ID
40x: ID

Which cell can be used to focus on the correct plane in a urine specimen?

Epithelial Cell

Which urine elements are reported by lower power field? And high power field?

10x: casts
40x: RBCs, WBCs

If the sample is red, turbid, and tests positive for Blood and Protein, what microscopic elements can you expect?

RBCs

If the sample is turbid and tests positive for Protein, Nitrite, and Leukocyte Esterase, what microscopic elements can you expect?

WBCs

If the sample is turbid and tests negative for everything else, what microscopic elements can you expect to see?

Epithelial cells

If the sample is cloudy and tests positive for Protein, what microscopic elements can you expect to see?

Casts

If the sample is turbid, has a higher pH, and tests positive for Nitrite, and Leukocyte Esterase, what microscopic elements can you expect to see?

Bacteria

If the sample turbid, has color, an acidic pH and tests positive for Bilirubin, what microscopic elements can you expect to see?

Crystals

What are some advantages to using stain on urine sediment?

Increases visibility
Easier ID of nucleus, cytoplasm, and inclusions

List 6 urine sediment stains and their use

Crystal Violet: provides clearer delineation of structure and contrasting colors of the nucleus and cytoplasm
Acetic Acid: enhances nuclear detail of WBCs & epithelial cells
Lipid Stains: stains Triglycerides and neutral fats
Gram Stains: differentiation of gram-positive and gram-negative bacteria. ID of bacterial casts
Hansel Stain: urinary eosinophil detection
Prussian Blue Stain: Stains hemosiderin granules in a blue color

How does cytodiagnostic urinalysis differ from routine microscopic examination?

Cytodiagnostic urinalysis uses permanent slides

List 6 types of microscopy discussed for urine examination and list one function for each.

Bright-field: Routine urinalysis
Phase-contrast: enhances visualization of elements with low refractive index
Polarizing: aids in ID of cholesterol in oval fat bodies, fatty casts, and crystals
Dark-field: aids in ID of Treponema Pallidum
Fluorescent: allows visualization of naturally fluorescent or microorganisms stained by a fluorescent dye
Interference-contrast: produces a 3D microscopy image and layer-by-layer imaging of a specimen

What should the light intensity of the microscope be for examining urine sediment?

Low light

How is the light intensity regulated on the microscope?

Light condenser knob

What does birefringent property refer to in an object?

the ability to refract light in 2 directions

List two urine elements that have birefingent properties.

artifacts and crystals

List 6 formed elements that may be observed in urine sediment.

RBCs
WBCs
Crystals
Epithelial cells
Casts
Yeasts

What is the significance of red cells in urine?

Damage to glomerular membrane or vascular injury to genitourinary tract

Which elements may be confused with rbcs microscopically?

Yeasts
Oil droplets
Air bubbles
Starch

Which chemical test on dipstick should correlate with microscopic rbcs in urine?

Blood
Specific Gravity
Color

Describe the appearance of rbc in hypersthenuric urine and hypothenuric urine.

Hypersthenuric: crenated
Hypothenuric: Ghost cells

What is the significance of white cells in urine?

Infections
Immune system response

What is a glitter cell?

WBC that expands in hypotonic urine, exhibits Brownian movement

Which WBC is the predominant white cell found in urine?

Neutrophils

Which chemical test on dipstick should correlate with microscopic wbcs in urine?

Clarity
Leukocyte Esterase
Nitrite

List and briefly describe the three types of epithelial cells seen in urine, and state their sitesof origin.

Squamos: Vagina, male and female urethra
Transitional: bladder, renal pelvis, calyces, ureters, upper male urethra
RTE: renal tubules

Which of the three epithelial cells is significant and why?

RTE
Indicates tubular necrosis

Which type of urine collections may limit the number of contaminated squamous epithelial cells in urine sample?

midstream clean-catch

Name and describe a clinically significant form of squamous epithelial cells. Describe the appearance of cell.

Clue cell
Granular cell appearance

What is the significance of the different shapes of renal tubular cells?

The different shapes indicate where they originated from

How is the WBC and RTE cells differentiated?

RTE cells are larger

Name three substance RTE may absorb and show up in RTE appearance.

Heavy metals
Drug induced toxicity
Hemoglobin and Myoglobin toxicity

What are oval fat bodies and state the clinical significance. Describe one identificationusing polarized light.

Fat laden Rt cells
Nephrotic syndrome, glomerular syndrome, RT cellular death
Maltese cross formation

What would be a possible indication if bacteria and wbc are seen in urine?

UTI

What is the most common significance of bacteriuria in the absence of WBCs?

Specimen left at room temperature too long

Which chemical test on dipstick should correlate with microscopic bacteria in urine?

Alkaline pH
Leukocyte Esterase
Nitrite

Why are yeast cells misidentified as rbcs? Which dipstick test should be correlated for rbc?

Neither contain a nucleus
Blood

Which dipstick test may be positive if yeast is present in fresh urine?

Glucose
Leukocyte Esterase

List 3 parasites that may be found in urine and indicate significance.

Trichomonads: Sexually tramsitted
Schistosoma Haematobium: bladder cancer
T. Vaginalis: vaginal inflammation

Why do casts vary in size and composition?

Vary depending on what they pick up

What is the primary constituent that all casts have in common?

Uromodulin

State the primary condition required for the formation of casts.

Stress or exercise

Explain the difference in the clinical significance of free RBCs or WBCs versus RBC castsand WBC casts in the urine sediment.

Casts indicate issues with the nephron
RBC casts indicate bleeding in the nephron
WBC casts indicate infection in the nephron

Describe two methods by which granular casts are formed.

Lysomes excreted by RTE cells
Disease states
Disintegration of cellular casts and tubular cells

What do waxy and broad casts have in common?

Both are caused by urine stasis

Since most urinary crystals are not clinically significant, why is it necessary to identify them?

A few abnormal types can signify liver disease, inborn errors of metabolism, and damage to tubules

Why is pH important in identifying crystals?

Different crystals form under different pHs

At which pH do abnormal crystals precipitate?

Acidic urine

Which microscopy characteristic is valuable in crystal identification?

Shape and color

How can amorphous urates and amorphous phosphates be dissolved to aid obscured field?

Amorphous Urates: warming in a water bath
Amorphous Phosphates: Acetic acid

Which pH is amorphous urates found? Amorphous phosphates?

Amorphous Urates are in acidic urine
Amorphous Phosphates are in alkaline urine

What are the most common normal crystals observed in acidic urine?

Amorphous Urates
Uric acid
Acid urates
Sodium urates
Calcium Oxalate

What are the most common normal crystals observed in alkaline urine?

Amorphous Phosphates
Triple Phosphate
Calcium Phosphate
Calcium Carbonate
Ammonium Biurate

How is the identity of abnormal urines confirmed?

Patient disorders and medications

List 8 abnormal crystals that may be found in urine.

Cystine
Cholesterol
Radiographic Dye
Tyrosine
Leucine
Bilirubin
Sulfonomide
Ampicillin

What 3 urinary crystals may be seen with liver disease?

Tyrosine
Leucine
Bilirubin

Why would iatrogenic compounds precipitated in urine considered significant?

They can be caused by a variety of compounds

Name 4 possible artifacts seen in urine. What are two distinguishing microscopiccharacteristics of artifacts?

Fibers: longer, more refractile
Starch granules: highly refractile spheres, dimpled center
Air bubbles: highly refractile, resemble RBCs
Pollen grains: spheres with cell walls, occasional concentric circles

Name the identifying characteristics of: Amorphous Urates

Thin needles and seen in synovial fluid

Name the identifying characteristics of: Uric acid

Rhombode, Rosettes

Name the identifying characteristics of: Calcium Monohydrate

Ovoid calcium oxalate

Name the identifying characteristics of: Calcium Oxalate

Envelopes calcium oxalate

Name the identifying characteristics of: Amorphous Phosphates

White precipitate

Name the identifying characteristics of: Triple Phosphate

"Coffin lids"

Name the identifying characteristics of: Ammonium Biurate

Thorny apple phosphate

Name the identifying characteristics of: Calcium Phosphate

Thin prisms or flat rectangular plates

Name the identifying characteristics of: Calcium Carbonate

Dumbbell or spherical shape

Name the identifying characteristics of: Cystine

Hexagonal plates dye

Name the identifying characteristics of: Cholesterol

Notched corners

Name the identifying characteristics of: Tyrosine

Fine needles with clumps or rosettes seen in liver disease

Name the identifying characteristics of: Leucine

Concentric circles and radial striations

Name the identifying characteristics of: Bilirubin

Bright yellow clumped needles/granules

Name the identifying characteristics of: Ampicillin

Colorless needles with bundles following refrigeration

Name the identifying characteristics of: Radiographic Dye

Flat plates
High specific gravity/refractometer

Name the identifying characteristics of: Sulfonomides

Needles, rhombics, whetstones, sheaves of wheat, and rosettes with colors ranging from colorless to yellow-brown

RBCs

WBCs

Cystine

Uric Acid

Hyaline Casts

Triple Phosphate

Ammonium Biurate

What are reagent strips?

Strips that consist of chemical-impregnated absorbent pads