Urinalysis Flashcards
What are indications for performing a urinalysis?
- aid to search for diagnosis of disease
- screen patients for asymptomatic diseases
- monitor biologic behavior of disease
- monitor effectiveness and safety of therapy
What are the disorders of the urinary system?
- renal disease/failure
- bacterial infection
- hematuria
- neoplasia
- crystalluria
- urolithiasis
What is Uremia?
abnormal concentration of urine constituents in blood caused by generalized renal disease;marked by polysystemic toxic syndrome which occurs as a result of both kidneys being impaired. Uremic crises may result from disorders such as CHF, acute pancreatitis or endocrine crisis
What is Bacteriuria?
bacteria in the urine
What is Pyuria?
WBC’s in the urine
What is Hematuria?
blood in urine
What is Crystalluria?
crystals in urine
What are Uroliths?
stones in urine
What are the Non-Urinary Disorders?
- diabetes mellitus
- diabetes insipidus
- hepatic failure
- severe hemolytic disease
- pre renal azotemia
What conditions are associated with Diabetes Mellitus?
- hyperglycemia
- glucosuria
- ketonuria
What condition is associated with Hepatic Failure?
bilirubinuria
What is Pre-Renal Azotemia?
abnormal concentration of urea, creatinine and other nitrogenous substances in the blood; can be caused by an increased rate of production or decreased rate of removal in urine or both
What can the value of urinalysis be influenced by?
- diet being consumed
- condition of patient at time of sample collection
- method of sample collection
- sample handling and preservation
- testing methods
- medications
What is Micturition?
act of passing urine, voiding, “peeing”, etc.
What are the methods of sample collection?
- voided
- bladder expression
- catheterization
- cystocentesis
When should a sample be collected?
prior to beginning therapy (fluid or drug) in order to ensure accurate results
What type of sample is most concentrated and least affected by dietary factors?
early morning, pre prandial
What is the easiest method of sample collection?
voided
What can easily contaminate Voided samples?
bacteria in distal urethral (vulva/prepuce) secretions
Why can the WBC count be elevated in Voided samples?
due to inflammation of genital tract
What type of voided sample is least contaminated?
midstream sample
What can affect results of Table Top collected samples?
- cleanliness of table
- chemical agents/disinfectants
What can happen if too much pressure is applied during a Bladder Expression?
injure or rupture bladder
What kind of animals should you never use a Bladder Expression on?
animal’s with fragile bladder wall or with urethral obstruction
What may become increased due to pressure of a Bladder Expression?
RBC’s in sample
What is Catheterization?
polyproylene or rubber catheter is inserted into urethra to obtain urine sample
What may be seen due to trauma of urinary tract from a Catheter?
- RBC’s
- epithelial cells
Catheterization is an acceptable method of collection for?
culture and sensitivity testing when cytocentesis can’t be performed
When should a sample be collected by Cytocentesis?
when the bladder is distended (can be palpated or observed on ultrasound)
What needle and syringe size is used for a Cytocentesis?
20-22 gauge, 1 or 1/2 inch needle, 10ml syringe
What position should the animal be during a Cytocentesis?
- standing
- lateral recumbancy
- dorsal recumbancy
Where is the needle inserted during a Cytocentesis?
caudal abdomen on midline (side of penis in males)
What is commonly seen due to trauma of bladder wall via needle puncture?
RBC’s
What are predictable changes that happen to urine when left at room temperature for long periods of time?
- decrease glucose and bilirubin
- alkaline pH
- crystal formation
- increased turbidity
- breakdown of casts and RBC’s
- bacterial proliferation
How long does refridgeration preserve most urine constituents?
6-12 hours
What can form (or degrade) when sample is refidgerated then brought to room temp?
crystals
When must a preservative be added to the urine sample?
- when sending samples to outside lab
- sample must be held for longer than 12 hours
What is the preservative of choice?
1 drop of 40% formalin per 1oz of urine
What are other less common preservatives?
- thymol crystal
- 5% phenol
- toluene
What should a urinalysis report include?
- patient information
- collection technique
- date and time of collection
- method of preservation (if used)
- complete results
What is done to maintain Quality Assurance?
- keep reagent strips and tablets in tightly sealed bottles
- replace outdated reagents with fresh reagents
- use controls to monitor results
What is a Control?
biologic solution of known values, used for verification of accuracy and precision of test results
What are the 3 categories of findings?
- physical findings
- chemical findings
- microscopic findings
What is recorded under Physical findings?
- color
- transparency
- odor
- volume
- USG
What is recorded under Microscopic findings?
crystals, casts, bacteria, yeast, aritfacts, WBC’s, RBC’s, epithelial cells, fungi,
What are the Physical Properties of Urine?
- volume
- color
- odor
- specific gravity
What factors affect Urine Volume that are unrelated to disease?
- fluid intake
- external losses (sensible, insensible, contemporary)
- environmental temperature and humidity
- amount and type of food fed
- level of physical activity
- species and size of animal
What is the ideal way to deterimine Urine Volume?
24 hour urine volume collection
What is the normal daily output of dogs and cats?
20-40ml/kg
What is Polyuria?
increase in daily output of urine
What conditions/diseases is Polyuria seen?
- steroids
- diabetes mellitus/insipidus
- nephritis
- diuretics
- fluid admin
What is Pollakiuria?
increased frequency of urination
What conditions/diseaes is Pollakiuria seen?
marking
What is Oliguria?
decreased daily urine output
What conditions/diseases is Oliguria seen?
- dehydration
- decreased fluid intake
- vomiting
- diarrhea
- increased body temp
- fever
- shock
- heart disease
What is Anuria?
no urine output
What conditions/diseases is Anuria seen?
- complete blockage
- trauma
- ruptured bladder
- shut down kidneys
What is Stranguria?
straining to urinate
What conditions/diseases is Stranguria seen?
- UTI
- blocked tom
- prostatits
What is Polydipsia?
increased fluid intake
What conditions/diesease is Polydipsia seen?
- seen with polyuria
- diabetes…etc..
What is the normal color of urine?
light yellow to amber due to presence of urochromes (urobilinogen)
Colorless urine
- low USG
- associated with polyuria
Dark yellow to yellow brown urine
- high USG
- associated with oliguria
Yellow-brown, green or greenish yellow; foamy urine
contains bile pigments
Red or red-brown urine
idicates hematuria or hemoglobinuria
Brown urine
contains myoglobin
What kind of odor does male cats, goats and pigs have?
strong
What kind of odor may occur with cystitis?
amonia
caused by bacteria that produce urease
What can happen to samples left standing at room temp (odor)?
ammonia odor from bacterial ingrowth
What does a sweet or fruity odor urine indicate?
ketones
What are Ketones in the urine associated with?
- diabetes mellitus
- ketosis in cows
- pregnancy disease in sheep (postparturent ketosis, eclampsia)
What is Specific Gravity?
weight (density) of a quantity of liquid compared with that of an equal amount of distilled water
What is the most common way to determine Specific Gravity?
refractometer
What does interpretation of Specific Gravity yield?
info on hydration status and the ability of kidneys to concentrate or dilute urine
What does the USG of normal urine depend on?
- eating and drinking habits
- environmental temperature
- time of sample collection
What urine samples tend to be the most concentrated?
early morning, mid urination
What is the normal USG range for dogs?
1.001-1.060 (1.025)
What is the normal USG range for cats?
1.001-1,080 (1.030)
Increased USG is seen with what?
- decreased water intake
- increased fluid loss through sources other than urination (sweating, panting, diarrhea)
- increased excretion of urine solutes
Decreased USG is seen with what?
- diseases in which the kidneys cannot reabsorb water
- increased fluid intake such as polydipsia or excessive fluid admin
What is Isosthenuria?
USG is equal to specific gravity of plasma
1.008-1.012
In what conditions is Isosthenuria seen?
- chronic renal disease; the closer the USG is to glomerular filtrate, the greater amount of kidney function thats been lost
- normal renal function that have no need to concentrate urine
What is Hyposthenuria?
USG is lower than normal
What is the ability to concentrate urine depend on?
ADH and sufficient number of function nephrons and tubules of both kidneys
What is Hypersthenuria?
USG is higher than normal
What is the Dehydration range of USG in dogs?
1.050-1.070
What is the Dehydration range of USG in cats?
1.050-1.085
What is the SG of plasma (glomerular filtrate)?
1.010
What are the Chemical Properties of Urine?
- pH
- protein
- glucose
- ketones
- bilirubin
- urobilinogen
- nitrite
- blood
- leukocytes
What % of water and solutes does urine consist of?
- 95% water
- 5% solutes (urea, sodium, potassium, phosphate, sulfate, creatinine, uric acid, hormones)
What are the most common chemical properties tested in Vet Med?
- pH
- protein
- glucose
- ketones
- urobilinogen
- bilirubin
- blood/hemoglobin
- leukocytes
What is pH?
measurement of hydrogen ions concentration
What is urine pH a function of?
kidney’s ability to regulate H+ and bicarbonate concentration within the blood
What is the normal pH of cats and dogs?
6.0-7.0
What happens if the urine is too acidic or alkaline?
specific crystals or uroliths can form
What happens to the pH of samples left standing at room temp?
pH increases due to loss of carbon dioxide
What does the pH of urine depend on?
diet
What urine pH does a carnivore have?
acidic
What are causes of Acidic Urine?
- metabolic or respiratory acidosis
- vomiting
- severe diarrhea
- fever
- starvation
- prolonged exercise
- urinary acidifiers
What are causes of Alkaline Urine?
- metabolic or respiratory alkalosis
- bacterial infections
- renal tubular acidosis
Is protein usually present or absent in urine?
absent
What causes trace amounts of protein to be present in urine?
samples obtained via catheterization, cystocentesis or bladder expression due to trauma (RBC’s)
Why is there Protein in the urine from Voided Samples or Bladder Expression?
secretions that contaminate urine during passage along genital tract
What do Reagent Strips primarily detect?
albumin
What can cause false positives when using Reagent Strips?
occur in alkaline urine depending on diet, UTI or urine retention due to urethral obstruction
How is the Urine Protein/Creatinine Ratio obtained?
dividing protein concentration by creatinine concentration
What are Reagent Strips a screening tool for?
proteinuria
What is Urine Protein/Creatinine Ratio used to confirm?
proteinuria findings on dipstick
When should you not perform a Urine Protein/Creatinine Ratio?
when there is bacteria in the urine
What can yield false negative results in a Urine Protein/Creatinine Ratio?
very dilute urine, concentration may be below the sensitivity of testing method used
What does Transient Proteinuria result from?
temporary increase in glomerular permeability, allowing excess protein to enter filtrate
What are causes of Temporary Proteinuria?
muscle exertion, stress, convulsions, after partuition, during first few days of life, during estrus
What does Proteinuria indicate?
in many cases, indicates disease of urinary tract, especially kidneys
What is Glycosuria?
presence of glucose in urine
Is glucose normal or abnormal in urine?
abnormal
When does Glucosuria occur?
when blood glucose level exceeds the renal threshold
What can cause False Positives in Glucose testing?
various drugs: vitamin C, morphine, asprin, penicillin, and other antibiotics
What may lead to blood glucose levels exceeding renal threshold?
high carb meal
Fear, excitement or restraint in cats can cause what?
hyperglycemia and glucosuria as a result of epinephrine release
What disease is commonly seen with Glucosuria?
- diabetes mellitus
- cushing’s
- pancreatitis
What are Ketones?
chemical compounds normally produced during fat metabolism
Ketones include:
- acetone
- acetoacetic acid
- beta-hydroxybutyric acid
What Ketones are Reagent Strips most sensitive to?
acetoacetic acid
What Ketone do Reagent Strips not detect?
beta-hydroxybutyric acid
What Ketone is primarily responsible for producing acidosis?
beta-hydroxybutyric acid
Are Ketones normally found in the urine?
no
Conditions characterized by altered metabolism may result in what?
excessive amount of fat catabolism to provide energy
What problems develop with excessive Ketones?
- CNS depression
- ketoacidosis
What is Ketonuria associated with?
diabetes mellitus
Ketonemia with ketonuria occurs with?
- high fat diets
- starvation
- fasting
- long term anorexia
- persistant fever
- impaired liver function
What are causes of Bilirubinuria?
- fever
- starvation
- intravascular or extravascular hemolysis (hemolytic disease)
- intrahepatic or extrahepatic biliary obstruction
Is Urobilinogen normal in urine?
yes
What are true reasons for increased values of Urobilinogen?
- liver dysfunction
- hepatic infection
- excessive hemolysis
- increased urobilinogen production
- re absorption
- poisioning
What are reasons for true absence or very low values of Urobilinogen?
- failure of bile production
- obstruction of bile passage
Why do Nitrates occur in urine?
bacterial infections
What must occur in order to achieve a positive result of Nitrate?
urine must be retained in bladder atleast 4 hour
A positive Nitrate test indicates what?
bacterial infections, gram negative rods
What do tests for blood in urine detect?
- hematuria
- hemoglobinuria
- myoglobinuria
What is Hematuria?
whole blood in urine
What is Hematuria usually a sign of?
disease that has caused bleeding somewhere in the urogenital tract
What is Hemoglobinuria?
lysed RBC’s in urine
What is Hemoglobinuria a result of?
intravascular hemolysis (IMHA, incompatable blood transfusions, leptospirosis, babesiosis, poisionous plants, water intoxication in cattle)
What does Myoglobinuria result from?
severe muscle damage causing myoglobin to leak from muscle cells into blood
How do you distinguish myoglobinuria from hemoglobinuria?
look at history and c/s
What causes false negatives in Leukocyte testing?
- especially in dogs
- glucosuria
- elevated USG
- certain antibiotics (tetracycline)
What causes false positives in Leukocyte testing?
- occurs in ALL cats
- old samples, fecal contamination
- epinephrine release (neutrophilia)
- certain drugs or food
- microscopic eval. necessary to confirm positive result
Microscopic evaluation is important especially for:
recognizing diseases of the urinary tract
What animals have normal sediment in their urine?
horses and rabbits
What is the collection method of choice for microscopic examination?
cystocentesis
What are the constituents of urine sediment?
- WBC’s
- RBC’s
- epithelial cells
- casts
- crystals
- microorganisms
- parasites
- ova
- miscellaneous
What do RBC’s look like in fresh urine?
- small
- round
- smooth edges
- refractile
- yellow or orange
- may be colorless if hemoglobin has diffused during standing
What do RBC’s look like in concentrated urine?
shrink and crenate
What do RBC’s look like in dilute or alkaline urine?
swell and may lyse
What do WBC’s look like in urine?
dull gray or greenish-yellow
What happens to WBC’s in concentrated urine?
shrink
What happens to WBC’s in dilute urine?
swell
What findings of WBC’s indicate inflammatory process in urinary or gential tracts?
2-3 / hpf
What is Pyuria?
excess of WBC’s in urine
Are epithelial cells normal in urine?
yes
What are the 3 types of epithelial cells found in urinary sediment?
- squamous
- transitional
- renal
Where do squamous epithelial cells come from?
- distal urethra
- vagina
- vulva
- prepuce
- presence is normal
Where do Transitional Epithelial Cells come from?
- bladder
- uterus
- renal pelvis
- proximal urethra
What do increased numbers of transitional epithelial cells suggest?
- cystitis
- pyelonephritis
What are the smallest epithelial cells seen in urine?
renal epithelial cells
What do increased numbers of transitional epithelial cells suggest?
parenchyma
Where do casts come from?
renal tubules
secreted protein precipitates in ACIDIC conditions
How are casts classified?
- hyaline
- epithelial
- cellular
- granular
- waxy
- fatty
- mixed
What does cast type depend on?
- how quickly filtrate is moving through the tubules
- how much tubular damage is present
Casts dissolve in what kind of urine?
alkaline
What can disrupt casts?
high speed centrifugation
What do Hyaline casts look like?
colorless and transparent
rounded edges
What are Hyaline casts composed of?
only protein
What do Hyaline casts indicate?
- mildest forms of renal irritation
- fever
- poor renal perfusion
- strenous exercise
- general anesthesia
Where do Epithelial cells originate from?
renal
What do Epithelial cells most commonly result from?
when ischemia, infarction or nephrotoxicity cause degeneration and necrosis of tubular epithelial cells
What do Leukocyte casts contain?
- WBC’s
- primarily neutrophils
What does the presence of Leukocyte casts indicate?
inflammation of renal tubules
What do Erythrocyte casts look like?
deep yellow to orange in color (membranes may or may not be visible)
When do Erythrocyte casts occur?
when RBC’s aggregate within the lumen of the tubule
What do Erythrocyte casts indicate?
renal bleeding (hemorrhage resulting from trauma or bleeding disorders or as part of inflammatory response)
Where do Granular casts come from?
tubular epithelial cells, RBC’s or WBC’s that became incoporated into cast and then degenerate
When are Granular casts seen?
acute nephritis and indicate more severe kidney damage than do hyaline casts
Where are Fatty casts commonly seen?
cats with renal disease
diabetic dogs
What do Waxy casts look like?
- resemble hyaline casts, but wider and with square ends
- waxy appearance, colorless or gray and highly refractile
What do Waxy casts represent?
latter stages of cast development/degeneration
What do Waxy casts indicate?
severe chronic degeneration of tubules
What is Crystalluria?
presence of crystals in urine
What does the type of casts formed depend on?
pH (diet)
concentration, temperature, solubility of elements
What are the only definitive methods of identifying crystals?
- optical crystallography
- x ray diffraction
- chemical analysis
What are the most common type of crystals in cats and dogs?
struvite
What promotes Struvite Crystalluria?
UTI with urease-posititve bacteria, by raising urine pH and increasing free ammonia
What do Struvite Crystals look like?
coffin lids or prisms
How many sides do Struvite crystals have?
6-8
What are Struvite crystals commonly referred to as?
- triple phosphate
- magnesium ammonium phosphate
In what kind of urine are Struvite crystals found?
alkaline to slightly acidic
Where do Amorphous Phosphate crystals form?
alkaline urine
How do Calcium Carbonate crystals appear?
- rounded with many lines radiating from the center
- large granular masses
- dumb bell shaped
Where are Calcium Carbonate crystals found?
neutral to alkaline urine
Calcium Carbonate crystals are normal findings in:
horses and rabbits
Where do Amorphous urates form in?
acidic urine
Where do Uric Acid crystals commonly occur?
dalmations, bulldogs
cant process purines
Where do Urates and Uric Acid Crystals form?
acidic acid
Ammonium Biurate Crystals are also known as:
thorn apples
Where do Ammonium Biurate Crystals form?
neutral to alkaline urine
What disesae are Ammonium Biurate Crystals seen with?
severe liver disease
Where are Calcium Oxalate crystals formed?
acidic and neutral urine
Where are Calcium Oxalate crystals commonly seen?
small numbers in dogs and horses
When are Calcium Oxalate Monohydrate crystals seen in large amounts?
antifreeze poisioning
Where do Tyrosine Crystals formed?
acidic urine
What are Tyrosine crystals associated with?
liver disease
Where do Cystine Crystals form?
acidic urine
What are Cystine crystals associated with?
renal tubular dysfunction or canine urolithiasis
Where are Bilirubin crystals seen?
canine urine, especially in high concentrated specimens
What microorganisms are seen in urine?
bacteria
parasite ova and microfilaria
yeast and fungi
How are Bacteria in urine identified?
high power magnification
Why may bacteria appear to be quivering?
brownian movement
What does a large number of bacteria accompanied by WBC’s suggest?
infection and inflammation of urinary tract or genital/reproductive tract
What are the parasites of the Urinary Tract?
dioctohyma renale
capillaria plica
What is Yeast commonly confused with?
RBC’s or lipid droplets
What are the Miscellaneous Components of Urine?
- mucus threads
- spermatozoa
- fat droplets
- artifacts
What are Mucus threads commonly confused for?
casts
What are Mucus threads indicative of?
urethral irritation or contamination of sample with genital secretions
Where are large amounts of Mucus threads normally present?
urine of horses
Where is Spermatozoa occasionaly seen?
sediment of intact males
recently bred females
What is Lipiduria seen with?
obesity
diabetes mellitus
hypothyroidism
rarely, after a high fat meal
When do Artifacts enter samples?
during collection, transportation or examination
What are examples of Artifacts?
air bubbles, oil droplets, starch granules, hair, fecal material, plant spores, pollen, cotton fiber, dust, glass particles or chips, bacteria and fungi
