108.5 Microscopic Examination Chapter07 2022.23

What kind of elements are seen in a microscopic examination?

• Red blood cells (RBCs)

• WBC

• Epithelial cells

• Casts

• Bacteria

• Yeast

• Parasites

• Mucus

• Spermatozoa

• Crystals

• Artifacts

What field should casts be look on

Low power field (10x)

Sediment Stains

Increases the overall visibility of sediment using bright-field microscopy by changing refractive index

imparts identifying characteristics of cellular

structures = Nuclei, Cytoplasm, Inclusions

Supravital Stains

Sternheimer-Malbin stain : crystal violet /Safranin O

Useful in the differentiation between WBCs and renal tubular epithelial cells

provides clearer delineation of structure and contrasting colors of the nucleus and cytoplasm

Acetic Acid

Acidic acid will enhance nuclear detail of WBC and epithelial cells

RBCs are lysed by the acetic acid

Lipid Stains

Oil Red O and Sudan III stains are used and polarizing microscopy

Triglycerides and neutral fats stain orange-red

Cholesterol does not stain and capable of polarization

Gram Stain

Used primarily for the differentiation between gram-positive (blue) and gram- negative (red) bacteria

Identification of bacterial casts

Hansel Stain

Preferred stain for urinary eosinophils

Consists of methylene blue and eosin Y in methanol

Prussian Blue Stain

Hemosiderin granules seen with hemoglobinuria

Prussian blue stain for iron is used and stains the hemosiderin granules a blue color

Bright Field

Most often used in routine urine testing

Low light with condenser in low position

Phase-Contrast

phase-contrast objective lens and a matching condenser

enhances visualization of elements with low refractive indices, such as hyaline casts, mixed cellular casts, mucous threads, and trichomonas vaginalis

objects with low refractive index

Polarizing

Used to identify crystals, fat elements which are bifringent

Aids in identification of cholesterol in oval fat bodies, fatty casts, and crystals

Dark- field

Aids in identification of Treponema pallidum

Fluorescence microscopy

allows visualization of naturally fluorescent microorganisms or those stained by a fluorescent dye, including labeled antigens and antibodies

Interference- contrast

produce a three- dimensional microscopy image and layer- by- layer imaging of a specimen

RBC ( red blood cells)

Smooth, nonnucleated, biconcave disks ~7 µm

Crenated in hypersthenuric urine

Ghost cells in hyposthenuric urine

Identify using high power

WBC (White blood cell)

12 µm

Neutrophil is predominant

Identify under high power

Glitter cells

What are the three types of epithelial cells

squamous, Transitional, Renal tubular epithelial

Squamous

Largest cell in urine

Good for focusing microscope

Rare, few, moderate, many

lpf or hpf per laboratory

Normal sloughing

Contamination if not midstream clean-catch

What are the three forms of a transitional epithelial cells

Spherical, Polyhedral, Caudate

Spherical

absorb water in bladder and become

large and round

polyhedral

multiple sides

Caudate

has a tail

Transitional epithelial cell

Centrally located nucleus

Reported as rate, few, moderate, many

Syncytia = clumps

Renal Tubular Epithelial Cells

Size and shape vary with renal tubular area

Columnar = (larger)proximal convoluted tubule

(PCT)

Round, oval = (smaller) distal convoluted

tubule (DCT)

Cuboidal = collecting duct, never round

Three or more cuboidal cells = renal fragment

RTE in Proximal Convoluted Tubule Cells

Larger

than other RTEs

Columnar, convoluted,

rectangular

May resemble casts

Coarsely granular

cytoplasm

Examine for presence of

nucleus

RTE in Distal Convoluted Tubule Cells

Round or oval shaped,

smaller

May be mistaken for

WBCs or spherical

transitional cells

Observe the

eccentrically placed

nucleus to differentiate

from spherical

transitional

RTE in the Collecting Duct

Cuboidal, never round

At least one straight edge

Eccentric nucleus

Three or more cells in clump is renal

fragment; often large sheets

PCT and DCT not seen in clumps

Hyaline Casts

Nonpathologic: stress,

exercise, heat exposure,

dehydration

Pathologic: acute

glomerulonephritis,

pyelonephritis, chronic

renal disease,

congestive heart failure

RBC Cast

Glomerular damage or nephron capillary

damage

Glomerular damage: dysmorphic RBCs and

elevated protein

May be seen following strenuous exercise

orange to red color

WBC Casts

WBC casts are seen with infection and

inflammation of the nephron

Pyelonephritis: WBC casts, bacteria

Acute interstitial nephtitis: WBC casts, no

bacteria

May accompany RBC casts in

glomerulonephritis

Bacterial Casts

Seen in pyelonephritis

May be pure bacteria or mixed with WBCs

Identification is difficult, resemble granular

casts

Look for free WBCs and bacteria

Confirm with Gram stain

Seen in pyelonephritis

Renal Tubular Epithelial Cell Casts

Tubular damage, heavy

metals, viral infections,

drug toxicity, graft

rejection, pyelonephritis

Cells may appear

bilirubin stained

Look for matrix to

distinguish fragments

Fatty Casts

Nephrotic syndrome, diabetes, crush

injuries, tubular necrosis

Seen with oval fat bodies (OFBs) and fat

droplets

Highly refractile, OFBs may attach to matrix

Polarized microscopy and lipid stain

Triglycerides and neutral fats stain orange

Granular Casts

Coarse and finely

granular

Granule origin

RTE lysosomes, excreted in

normal metabolism, more

after exercise and activity

Disease states:

Disintegration of cellular

casts and tubule cells or

protein aggregates filtered

by the glomerulus

Waxy Casts

Brittle, highly refractile

Often fragmented with

jagged ends and

notches

Stains a homogenous

dark pink

Degenerated hyaline

and granular casts

Extreme urine stasis

Renal failure

Broad Casts

Renal failure casts

Destruction and

widening

of the DCTs

Formation in the upper

collecting duct

All types of casts may be

broad

Most common are

granular and waxy

Bile stained from viral

hepatitis

What crystals are seen in Acidic Urine

Amorphous urates

Uric acid

Acid urates

Sodium urates

Calcium Oxalate

Amorphous urates

Yellow-brown granules microscopically

pH usually greater than 5.5

Uric acid crystals

Rhombic, whetstones, wedges, rosettes

Yellow-brown color

Calcium oxalate crystals

Acid and neutral pH

§

Dihydrate is envelope or two pyramid–shaped

Most common

§

Monohydrate is oval or dumbbell shaped

Antifreeze poisoning

What crystals are seen in Alkaline Urine

Amorphous phosphates

Triple Phosphate

Calcium Phosphate

Calcium carbonate

Ammonium biurate

Amorphous phosphates

Alkaline pH and heavy white precipitate after

refrigeration

Granular in appearance

Triple phosphate

Colorless, prism, or coffin-

lid shaped

Highly alkaline urine and

urinary tract infections

(UTIs

Calcium phosphate

Colorless, flat rectangles

and thin prisms in rosettes

Calcium carbonate

Small, colorless, dumbbell,

and spherical shapes

Ammonium biurate

Yellow-brown, spicule-

covered spheres;

“thorny apples”

What pH is abnormal urine crystals are found on

Acidic urine

What are abnormal Urine Crystals

Cystine crystals

Cholesterol

Radiographic Dye

Cystine crystals

Colorless, hexagonal, thin and thick plates

Cholesterol crystals

Rectangular plates with characteristic

notched corners

Radiographic Dye Crystals

Similar to cholesterol crystals, polarize

Patient history and comparison of results of

other UAs

Very high SG with refractometer

What crystals are associated with Liver Disease

Tyrosine Crystals

Leucine Crystals

Bilirubin Crystals

Tyrosine Crystals

Fine colorless to yellow needles in clumps or

rosettes

Leucine crystals

Yellow-brown spheres with concentric circles

and radial striations

Bilirubin crystals

Hepatic disorders

Clumped needles or granules

Characteristic bright yellow color

Viral hepatitis with tubular damage

Ampicillin Crystals

Ampicillin crystals appear as colorless

needles that tend to form bundles following

refrigeration

Extreme dehydration