Microscopic Examination of Urine

to detect and identify insoluble elements present in the urine specimen

What is the purpose of microscopic exam of urine?

Microscopic Exam

• Third part of urinalysis

• most time-consuming and the least standardized part

• confirms physical and chemical analysis

1. Routine Techniques

2. Special Techniques

3. Automated microscopy

What are the 3 methods of microscopic examinations?

1. Quantitative estimation of urinary sediments

   • Hausser’s method

   • Long Coefficient method

   • Addis count

2. Application of stains

What are the special techniques of microscopic examination?

10—15 ml urine

What is the recommended volume of urine in microscopic examination?

5 minutes (1,500-2,000 rpm)

How many minutes is the centrifugation of urine in microscopic examination?

0.5-1.0 ml

What is the volume of sediment in microscopic exam after discarding the supernantant?

RCF (Relative Centrifugal Force)

What is the preferable to use that can produce minimal damage to cells?

Braking mechanism

What mechanism that slow centrifugation that cause disruption of sediments?

Prevent biohazardhous aerosols

What is to purpose of centrifuge in capped tubes?

• uniform amount of sediment - aspirate rather than poured off

• resuspend sediment by gentle agitation

• Use of pipettes in measuring the drop of sample

How do you prepare sediment?

Use of pipettes

What material should we use in measuring the drop of sample?

• Conventional coverslip method (20ul)

• 22mmx22mm coverslip

What method of coverslip shoul be used and what size?

prevent sediment to flow outside the coverslip (loss of heavier elements)

What should be prevented in the preparation of sediment?

• Organized sediments

• Unorganized sediments

What are the 2 types of urine sediments?

1. Cells

2. Casts

3. Mucus Thread

4. Microorganisms

5. Sperm Cells

What are the organized sediments?

Crystals

• normal crystals in acid urine

• normal crystals in alkaline urine

• Abornal crystals

What are the unorganized sediments?

• abnormal crystals of Iatrogenic origin (drugs)

• abnormal crystals of Metabolic origin

What are the 2 types of abnormal crystals?

• RBC

• WBC

• Epithelial cells

Enumerate the cells found in the sediment

• Squamous epithelial cells

• Transitional epithelial cells

• Renal Tubular epithelial cells

Enumerate Epithelial cells

RBCs

WBCs

Epithelial cells

Squamous

Transitional

Renal

Oval Fat Bodies

Bubble cells

distal convoluted tubule and collecting tubules

Where does the casts formed?

cylindrical with rounded or flat ends and are classified according to the substance observed in them

What is the shape of the casts and what are its classification?

representative of the tubular lumen

What does the shape of the casts represents?

Tamm-Horsfall mucoprotein or uromodulin

What is the major constituent of casts?

• hyaline cast

• cellular cast

Enumerate the type of casts

• RBC casts

• WBC casts

• Epithelial casts

What are the types of cellular casts?

Hyaline cast

RBC casts

WBC Cast

Transitional EC casts

Renal Tubular EC cast

Granular cast - fine or coarse

What type of cast that contain remnants of disintegrated cells that appear as fine of coarse granular embedded in the protein?

Waxy cast

What type of cast that is not normally seen in the urine but are associated with renal stasis?

Fatty cast

What type of cast that the important pathologic findings in the urine which indicate severe renal dysfunction?

Coarse granular

Fatty cast

Oval Fat Body Cast

Waxy casts

Fine granular

Bacterial cast

What type of casts that contain bacteria often associated with pyelonephritis?

Broad cast

What type of cast that is associated with renal failure cast?

Bacterial cast

Broad cast

• bacteria

• protozoa (flagellates)

• yeasts

What are the types of microorganism?

Bacteria

because of the movement of the flagella

How does protozoa usually recognized in urine sediment?

Trichomonas vaginalis

In protozoa, what is the most frequently seen parasite in urine?

Protozoa

smaller than RBC

What is the size of yeast cells?

ovoid

What is the shape of yeast cell?

in budding or in chains

How can we observe yeast cells?

Candida albicans

What is the most common yeast found?

Yeast cells

Sperm cells

Mucus Threads

• urine pH

• urine solubility

The identifcation of the types of (unorganized sediments) crystals depends on, what?

• Amorphous urates

• Uric acid

• Sodium urates

• Calcium oxalates

• Hippuric crystals

What are the normal crystals in acid urine?

• Amorphous phosphates

• Calcium carbonates

• Ammonium biurate

• Triple phosphate

• Calcium phophates

What are the normal crystals in alkaline urine?

1. Cystine

2. Tyrosine

3. Leucine

4. Cholesterol

5. Bilirubin

6. Hemosiderin granules

What are the abrnomal cyrstals of metabolic origin?

• appear as fine granules with no specific shape

• sediment may appear pink in the urine container but under the microscope the appear yellowish

What is the appearance of amporhous urates?

Amorphous urates

Uric acid

• appear as yellowish brown crystals that have a variety of shapes: irregular, rhombic clusters or rosettes

• large amount may be seen in patients with gout

What is the appearance of uric acid?

patients with gout

Where can we see large amount of uric acid?

• irregular

• rhombic clusters

• rosettes

What are the variety of shape of uric acid?

Sodium urates

• appear as light-yellow slender prisms may be single or in clusters

• no clinical importance

What is the appearance of sodium urates?

Calcium oxalates

• appear as colorless, octahedral crystals which are refractile and variable in size

• looks like “envelopes” having an X intersecting

What is the appearance of calcium oxalates?

Hippuric crystals

• rarely seen

• yellow-brown or clear

• resemble needle-like prisms or plate

What is the appearance of hippuric crystals?

Amorphous phosphates

• may appear as colorless, amorphous, granular masses in urine sediment

• solube in 10% acetic acid

What is the appearance of amporphous phosphates?

Calcium carbonates

• appear as small, colorless, dumbbell-shaped or leaf-shaped crystals

• no clinical significance

What is the appearance of calcium carbonates?

Ammonium biurate

• seen in old urine samples

• yellow to brown spheres with striation on the surface & also can show irregular projection called “thorny apple” crystals

What is the appearance of ammonium biurate?

Triple phosphates

ammonium magnesium phosphate

What is triple phosphates also known as?

• appear as colorless, highly refractile prisms having 3 -6 sides

• “coffin’lid” appearance

What is the appearnace of triple phosphates?

Calcium phosphates

• colorless and may appear as star-like or needle-like, through may also form plates

• show up alone or clusters

What is the appearance of calcium phosphates?

Cystine

• colorless, refractile, flat, hexagonal crystals, usually having unequal sides

• presence in the urine indicates cystinuria

What is the appearance of cystine?

Tyrosine

colorless or yellow fine, delicate needles arranged in sheaves

What is the appearance of tyrosine?

Liver disease or kidney damage

What does the presence of tyrosine in the urine means?

Leucine

appear as oily spheres that may be yellow-brown in color and are refractive

What is the appearance of leucine?

• liver disease or damage

• maple syrup urine disease (MSUD)

What indicates the presence of leucine in the urine?

Cholesterol

colorless, flat, rectangular plates with notched corners

What is the appearance of cholesterol?