TUTOR - Week 12

What is a urinalysis?

Series of diagnostic tests used to evaluate the urinary tract and kidneys

What does a complete urinanalysis include?

gross examination, urine specific gravity, dipstick analysis, microscopic evaluation of urine sediment

cyctocentesis

collecting urine sample directly from the bladder with a syringe and needle (usually used for culture)

What are different ways you can collect urine from a patient?

cystocentesis, catherization, voided/free catch, manual expression, off the floor

What are contraindications for cycstocentesis on patients?

uncooperative patient, evaluating hematuria (lood contamination happens commonly in these samples), concerns for bladder cancer (can seed or spread it)

What are contraindications for urinary catheterization?

uncooperative patient, not a sterile sample, can cause mucosal damage and secondary infection

What are contraindications with obtaining a free catch urine sample?

not a sterile sample, higher risk of contamination by patient environment

What are contraindications of manual bladder expression?

not a sterile sample, higher risk of contamination, trauma risk to patient (NEVER manually express in a suspect or blocked patient)

What are you looking at with the gross evaluation of a urine sample?

color, turbidity(clarity), specific gravity, odor

What can red to red/brown urine indicate?

presence of hemoglobin and or myoglobin

Hemoglobinuria

hemoglobin in the urine due to IV hemolysis causing hemoglobin to spill into urine

Myoglobinuria

myoglobin in the urine due to muscle breakdown, muscle injury, strenuous exercise

What can dark yellow, orange, or brown urine indicate?

presence of bilirubin

Bilirubinuria

bilirubin in the urine due to cholestatic or hepatobiliary disease (bile unable to move from liver to small intestine)

How do you determine if it's hemoglobinuria or hematuria?

centrifuge the sample, RBCs will create a red pellet at the bottom (hemolysis), Hemoglobin will remain pink/red throughout the sample

What species normally have more turbid (cloudy) urine?

equine and rabbits due to normal mucus and crystals

What causes cloudiness in urine?

cells (inflammation), protein, mucus, crystals, lipids

How do you evaluate turbidity?

white paper test (hold sample up to a paper with writing on it and see if you can see through it)

What are words you can use to describe turbidity?

clear, cloudy, hazy, opaque, etc.

How is urine specific gravity measured?

refractometer held up to light

What does urine specific gravity evaluate?

nephron (kidney) functionality, how well loops of Henle and distal tubules are diluting urine

What are the kidneys responsible for?

eliminate waste (urea + creatinine), fluid, electrolyte, and acid-base balance, nutrient conservation, erythropoietin production

What should you use to clean a refractometer?

distilled water and kim wipe only!

What is the normal USG for a canine?

1.030-1.040

What is the normal USG for a feline?

1.035-1.045

Hyposthenuria

decreased USG, kidneys are diluting the urine, USG: < 1.005

Isosthenuria

Fixed USG 1.008-1.012, kidneys are unable to concentrate or dilute, happens in renal failure (75% or greater nephron functionality loss)

Hypersthenuria

increased USG, dehydration

Polyuria/Polydipsia

increased urine volume, increased drinking

Anuria

no urine production, occurs secondary to disease, EMERGENCY!!

Oliguria

decreased urine production, hyperthermia

What artifacts can cause falsely elevated USG?

hyperglycemia, hyperproteinemia, contrast medium, wrong refractometer used

What artifacts can cause falsely decreased USG?

non-temperature regulation

What does chemical evaluation of urine include?

dipstick or reagent strips include: glucose, bilirubin, ketones, blood, pH, protein

What values are not reported from the urine dipstick?

leukocytes, specific gravity (always do with refractometer), ascorbic acid, nitrite, urobilinogen

How does glucose end up in urine?

normally reabsorbed in the proximal tubules of kidneys, kidneys have a threshold for glucose reabsorption and once it is met glucose gets excreted in urine

What is a dogs renal threshold for glucose?

180-220mg/dL

What is a cats renal threshold for glucose?

200-280mg/dL

What is a horse/calves renal threshold for glucose?

150mg/dL

When do you most commonly see glucosuria?

excited or stressed animals, diabetes mellitus and hyperadrenocorticism (Cushing's)

Bilirubin on dipstick

small amounts normal in canines, detects conjugated bilirubin only, IV hemolysis component

Bilirubinuria causes

hemolytic processes, cholestatis (slowing/block bile flow from liver), secondary to liver disease

What is the confirmatory test for bilirubin?

ictotest (positive is blue/purple color on test mat)

Ketones on dipstick

healthy animals test negative

What causes ketonuria?

shift from carbohydrate metabolism to lipid metabolism, causes negative energy balance and is not sustatinable

What do you most commonly see ketonuria in?

diabetes mellitus, diabetic ketoacidosis, starvation

What is the confirmatory test for ketones?

acetest or ketostix

The lower the pH the more _____ it is.

acidic

The higher the pH the more ____ it is.

alkaline

What is pH heavily influenced by?

diet

The more ____ the urine the more crystal formation and disintegration of RBCs WBCs and casts

alkaline

Normal pH for canine and feline urine

6.0-7.5

Normal pH for horses and cattle urine

7.5-8.5

Protein on dipstick

healthy animals have little to none (kidneys normally filter it out)

What causes proteinuria

renal disease, hemorrhaging, inflammation

What is the confirmatory test for protein in the urine?

suflosalicylic acid precipitation test (SSA) or urine protein: urine creatinine ratio (UPC)

What is the most accurate method for assessing proteinuria?

urine protein: urine creatinine ratio (UPC)

What is a urine protein:urine creatinine ratio used for?

screen for early renal disease, evaluate disease progression or underlying diseases, measure patient response to treatment

How is urine centrifuged?

10 minutes on lower RPM

Where should the microscope condensor be when evaluating urine sediment?

lowered all the way down and then 1 and 1/2 turns up to be in the middle

Should the light of the microscope be bright or dull when looking at urine sediment?

it should be more dull/less bright

What objectives of the microscope will you be using when looking at urine sediment?

10x and 40x

What is urine supernatant?

the liquid portion that sits on top of the sediment or pellet after being centrifuged (plasma or serum of the urine world)

What is urine supernatent used for?

re-suspend the sediment and run the UPC

What things will you see on low power (10x)?

casts, crystals, fungi, sperm, parasites

What things will you see on high power (40x)?

bacteria, epithelial cells, WBCs, RBCs, fat droplets

What do RBCs look like on urine sediment?

smaller than WBCS, round, clear to pale yellow in color with a yellow ring on the inside

RBC

What do WBCs look like on urine sediment

1.5 to 2 times larger than RBC, round, colorless and may have granules on the inside

WBC

pyuria

increase of WBC in the urine

What is the most common epithelial cell seen in urine?

squamous

What do transitional epithelial cells look like?

2-4 times the size of WBC, vary is shape from round to oval to polygonal

Where do transitional epithelial cells come from?

renal pelvis, ureter, urinary bladder, and urethra

What do renal epithelial cells look like?

larger than WBCs round with round nucleus

What does an increase of renal epithelial cells suggest?

renal tubule damage

What do squamous epithelial cells look like?

largest cell in urine, irregularly shaped, colorless, central nucleus with large amount of cytoplasm

Where do squamous cells orginate from?

vaginal tract, prepuce, or distal urethra

squamous epithelial cells

What is transitional cell carcinoma?

malignant neoplasia of epithelial cells seen with clumping of epithelial cells

transitional epithelial cells

What does bacteria look like on a urine sediment?

smallest urine element, can be either cocci (round) or rods (elongated), colorless, wiggles

Bacteria in urine

What does fat look like in urine?

small, round and can be clumped, colorless to yellow with black ring on outside, refractile and on a different plane (focuses up and down)

fat in urine

Where are casts formed?

loops of Henle, distal tubules, and collecting ducts

What are casts made of?

protein

What are the three types of casts?

hyaline, granular, waxy

What do hyaline casts look like?

vary is size, cylindrical shape with parallel sides, rounded/tapered/straight ends with the same diameter throughout, pale to colorless

Where are casts most commonly seen?

edges of the coverslip

What are causes of hyaline casts?

fever, strenuous exercise, diuretics, protein losing glomerular diseases

hyaline cast

What do granular casts look like?

vary in size, cylindrical with parallel sides, ends are rounded/tapered/straight with the same diameter throughout, pale to colorless, contains cells

granular cast

What do waxy casts look like?

vary in size, cylindrical with parallel sides, ends are blunt or fractured, pale to colorless

What do waxy casts indicate?

acute or chronic renal injury

Waxy cast

What causes formation of crystals in urine?

pH, temperature, concentration, and solubility of urine

Do refridgerated or fresh urine have more crystals?

refrigerated

What are struvite crystal characteristics?

large, rectangular with a line down the center, look like envelope, coffin, or prism, colorless and refractile