Microscopic Evaluation of urine

What does the microscopic tell us?

- evidence of renal disease as opposed to lower urinary tract infection

- indication of the type and activity of a renal lesion or disease condition.

What are microscopes that can be used for microscopic evaluation of urine?

bright field, phase contrast, and interference contrast.

What stains can be used for the microscopic evaluation of urine?

supravital stains and acetic acid

Where do casts like to go on a slide at 10x?

They tend to congregated near the edges of the coverslips

What is considered abnormal condition for RBC in urine?

>3/hpf

What does RBC cells, proteinuria, and RBC casts indicate?

glomerular or tubular bleeding

What does it indicate if there are RBC cells without proteinuria and RBC casts?

indicate bleeding below the kidney or contamination.

What is happening in hypotonic dilute urine with RBCs?

high pH, low specific gravity- cells swells up and release their hemoglobin (Ghost cells)

What do RBCs look like in a hypertonic culture?

Cells will be crenated

What causes RBCs to lyse with urine?

Cells will lyse with the addition of acetic acid

What does a large number of lymphocytes indicate?

early tissue rejection in kidney transplant patients

What is the limit of WBC that should not be exceed in urine?

should not exceed 3-4/hpf in normal urine

What is WBC's accompanied proteinuria indicate?

pyelonephritis

What is WBCs without proteinuria?

lower urinary tract infection

What are glitter cells?

It is hypotonic urine degenerated wbc's, cells expand and granules demonstrate Brownian movement.

What do renal tubular epis look like?

- round and slightly larger than leukocytes

- Each contains a single, large nucleus

What do large numbers of renal tubular epis suggest?

suggests renal disease

What do Squamous epithelium look like?

Large flat cells with single nucleus and large cytoplasm. edges can fold/curve making for unusual transformations

What do transitional epithelium look like?

Smaller than squamous cells, usually pear-shaped.

Where is transitional epithelium found?

located in renal pelvis, bladder

What can large numbers of transitional epithelium suggest?

disease of the bladder

What are casts?

Proteins in urine that congeal in the lumen of the nephron

What do casts look like?

Cylindrical bodies with a uromodulin protein matrix

What is Cast usually associated with and where is it generally formed?

- in distal and collecting tubules

- associated with proteinuria due to casts protein matrix

What are the classifications of homogenous matrix casts?

- Hyaline

- Waxy

What is normal limit of Hyaline cast?

2 or fewer per LPF

What can hyaline casts caused by?

- acute glomerulonephritis

- acute pyelonephritis

- malignant hypertension

- chronic renal failure

What do hyaline casts look like?

- colorless, transparent, and low refractive index.

What does the hyaline casts serve as?

the matrix for which all casts are formed.

What do waxy casts look like under the microscope?

- Highly refractile readily visible

- well defined edges, sharp, blunt, uneven ends

- cracks or fissures from lateral margins

Prolonged stasis and tubular obstruction

What is a waxy cast associated with?

tubular inflammation and degeneration, chronic renal disease

What does a WBC cast look like on a microscope?

Often look the cells are stuck to the outside.

What do WBC accompany and indicate?

they accompany proteinuria, bacteriuria and acute pyelonephritis

What do RBC cast look like on a microscope?

usually bright orange or reddish brown.

How will a RBC cast usually occurs?

diseases to the basement membrane of the glomerulus.

What should RBC casts be regarded as?

renal disease

Where are epithelial cell cast usually seen?

Generally renal tubular epis with in the protein matrix.

What is epithelial cell cast associated with?

- Inflammatory condition of the kidney.

- Suggests intrinsic kidney disease involving renal tubes

What accompanies Epithelial cell casts?

proteinuria almost always accompanies this.

What are mixed casts?

They have at least tow defined and distinct portions.

implies that more than one part of the nephron has been injured.

What are granular casts?

composed maidly of uromodulin protein and cast granulation

What do granular casts look like?

often colorless, shades of yellow, has all shapes and sizes. Coarse and finely granular

What do granular casts indicate

Pyelonephritis or lead intoxication

What are fatty a cast?

matrix contains free fat globules, oval fat bodies, and matrix can be hyaline or granular

What are bacteria that can be seen in urine?

- bacilli or cocci

- gram negative rods being the most common cause of UTI

What do yeasts most often represent?

a vaginal infection with subsequent contamination of the urine collection.

Who do UTIs usually effect that are caused by yeast?

commonly immunosuppressed patients

What is trichomonas vaginalis?

A contaminant from vaginal secretions

What is enterobius vermuclaris (pinworm)?

fecal contamination

What is mucus known as?

- delicate, ribbon like strands with irregular or serrated ends

- contaminant in the female vaginal epithelium

Why are crystals found in urine?

When chemicals are present in excess of their solubility.

What is the most frequently observed crystal and where is it seen?

Calcium oxalate in acidic urine, but can be seen in alkaline urine.

Dihydrate (normal) and monohydrate (dumbell)

Where are calcium oxalate stones found?

large number of kidney stones or ethylene glycol poisoning.

Why are calcium oxalate stones caused?

ingesting large amounts of oxalate rich foods, tomatoes, asparagus, vitamin C.

What are amorphous urates?

Urate salts

Acidic urine

Refrigeration enhances formation

Pink

uric acid

Colorless to yellow to golden brown in color

Acidic urine

Gout and chemotherapy

Sodium urate

Light yellow slender prisms

Crystals in alkaline urine

Triple phosphate, amorphous phosphates, ammonium biurate, calcium carbonate, calcium phosphate

All normal

Triple phosphate

Alkaline and neutral urine, coffin lids (3-6 sided prisms)

Enhanced by refrigeration

Urine stasis/chronic UTI (phosphates)

Amorphous phosphates

Common, nonpathologic

White precipitate in alkaline urine

Ammonium biurate

Alkaline urine, nonpathologic. Usually in old urine

Thorny apple

Calcium carbonate

Alkaline/neutral urine. Rare. Shaped like dumbells, rhombi, or needles

Produces carbon dioxide gas with acetic acid

Calcium phosphate

Neutral urine, sometimes acidic.

Colorless prisms/rosettes

Urine statis/chronic UTI (phosphates)

Abnormal crystals

All in acidic urine

Tyrosine and Leucine, cholesterol, cystine, bilirubin, antibiotics, x-ray dyes

Tyrosine

Abnormal (acidic urine). Thin dark needles, colorless or pale yellow-brown

When found alone, suggests rare inherited metabolic disorder

Leucine

Abnormal (acidic urine). Yellow/brown spheres with radial striations

When found alone, suggests rare inherited metabolic disorder

What is suggested when leucine and tyrosine are found together

Severe liver disease

Cholesterol crystals

Abnormal (acidic urine).

Clear, flat, rectangular plates with notched corners

Accompanied by large amounts of fat and protein

Cystine crystals

Abnormal (acidic urine).

Colorless, hexagonal plate, often layered.

Cystinuria

Bilirubin crystals

Abnormal (acidic urine).

Yellow/brown, fine needles

Positive bilirubin on dipstick, bilirubinemia

Antibiotic crystals

Abnormal (acidic urine).

Ampicillin - Long, colorless, thin prisms or needles that aggregate

Sulfonamides - Yellow/brown bundles of needles (sheaves of wheat)

X-ray dye crystals

Abnormal (acidic urine).

Specific gravity >1.040

Long, thin pointed rectangles or flat four-sided notched plates. Similar to cholesterol, but not accompanied by proteinuria or lipiduria