12a. Urine Collection, processing and physical examination

Question 1

How do we store and handle urine specimen?

Answer 1

diagnostic tests are of little value if sample has not be collected/stored properly
it can lead to an incorrect diagnosis and tx, or a condition can be missed completely

Question 2

What containers can we use for urine c

Answer 2

can be disposable or reusable
must be dry and free of chemical residue
transparent containers are useful for the physical examination of the urine but are not essential
when purchasing containers, they should be readily available, sturdy, leaf-proof and inexpensive - if storage and shipment is required, a tight-fitting lid is essential

Question 3

What are ways to collect urine?

Answer 3

1. natural micturition (free catch)
2. manual expression (also free catch)
3. Catheterization
4. Cystocentesis
   Make note of which one you use and be aware of the implications it’ll have on results

Question 4

How can we preserve samples?

Answer 4

urine is considered unstable so should be looked at asap or within 30-60 mins
longer it sits @ room temp, more alkaline sample will become
record when sample was collected and analysed

Question 5

What should you do if the sample will not be looked at within 30 minutes?

Answer 5

refrigerate the sample if it is not going to be processed within 30 minutes - use an opaque or amber container, keep away from light. Make sure it has a tight-fitting lid to prevent spilling, evaporation and contamination
Refrig is the most common form of short-term storage and preservation - can be used up to 12 hrs after collection

Question 6

What temperature do samples need to be before they are analysed?

Answer 6

Room temp. USG will be inc if urine is cold. Enzyme-based reactions are dec if cold, crystals can form in refrigerated samples - may not dissolve when urine is brought to room temp
Abnormalities found on stored samples should be retested on a fresh sample

Question 7

How can samples be stores for more than 12 hours? What ways can it be stored?

Answer 7

1 drop 40% formalin to 29.6 ml of urine - must do chem analysis first
Toluene sufficient to form a layer on top of the sample
one thymol crystal
one part 5% phenol to 9 parts urine
Unfortunately, no single preservative agent is satisfactory for all routine U/A tests

Question 8

How is urine physically examined?

Answer 8

before chem tests or a micro eval is performed, physical properties should be noted
1. urine volume and color
2. clarity/transparency
4. Odor
5. Specific gravity

Question 9

How do we evaluate volume of urine?

Answer 9

Owner often provides this info
Pollakiuria: More frequent urination
Polyuria: Increased VOLUME of urination
Can be influenced by species, BW and size, diet, fluid intake, physical activity, enviro factors such as temp and humidity

Question 10

What is the daily urine output in ml/kg for dogs, cats, cattle and horses?

Answer 10

dogs: 20-40ml/kg
Cats: 20-40
Cattle 17-45
Horses: 3-18

Question 11

What is polyuria?

Answer 11

the formation and elimination of excessive amounts of dilute urine
often associated with polydipsia
Can be termed physiological polyuria (normal) due to high fluid intake, high salt intake, fluid therapy, or meds (steroids/diuretics)
Or pathological polyuria (abnormal) - from diabetes insipidus and mellitus, CRF, ARF, nephritis, pyometra, hepatic disorders

Question 12

Why might polyuria be present with dehydration?

Answer 12

When kidneys are unable to conserve water despite the body’s dehydrated state
may be caused by renal failure, diabetic ketosis, pyometra and some liver disorders

Question 13

What is oliguria?

Answer 13

decreased urine formation by kidneys and/or decreased elimination of urine from the body?
can be physiological as a result of; dec water consumption, exposure to a warm environment
may be a response to dehydration, fever, vomiting
situation results in a small volume of urine that is usually very concentrated
it is reversible if the primary problem is corrected

Question 14

What is the range of urine color?

Answer 14

can be colorless to deep amber
usually related to degree of urinary concentration - may be due to presence of abnormal constituents within sample

Question 15

What happens when you collect a urine sample first thing in the morning? What happens to the color?

Answer 15

An animal’s first urination of the day is usually the most concentrated sample of the day, and therefore, darker in color
Must report urine color as part of the urinalysis
number of conditions result in a change the color of urine
eval urine color by placing sample in from of white bg

Question 16

What does it mean if we have a red or brown urine color?

Answer 16

often due to hematuria or hemogobinuria
fresh hemorrhage of urinary tract
must confirm presence of RBC’s with microscopic exam
proteinuria accompanies this color change
Intact RBC will sink when spun
hemoglobin will remain suspended

Question 17

Why might urine be brown or brown-tinged>

Answer 17

myoglobinuria
proteinuria accompanies this
color change on the chemical analysis of the urine

Question 18

What might cause a yellow-brown/green color in urine?

Answer 18

prods a greenish yellow foam when shaken
usually due to bilirubinuria - due to liver dz, hemolysis or the presence of bile
bilirubin is usually confirmed by microscopic or chemical means

Question 19

Why might urine be straw colored or colorless?

Answer 19

straw colored: dilute urine
Colorless: very dilute urine

Question 20

How might drugs affect the color of urine?

Answer 20

can prod a variety of color from pink to green or blue
an adequate history mus the taken

Question 21

How do we assess clarity and transparency?

Answer 21

clarity is a reflection of the number of particles present in the urine
how clear the urine is, NOT the color of the urine
an inc in turbidity may be caused by the presence of mucus, cells, vaginal secretions, sperm, crystals, bact, fat, Ca compounds, fecal and other contaminants
the underlying cause is determined by microscopic exam of urine

Question 22

What is the scale of transparancey?

Answer 22

1. clear - easily read thru the sample (minimal sediment present after centrifugation
2. Slightly cloudy: can still read thru sample but slight to mod distortion
3. Cloudy - cannot read thru sample, objects are blurred, sample usually contains large particles - significant amount of sediment is present after centrifugation
4. Turbid/flocculent - cannot see thru sample, suspended particles are present in sample and may be present to naked eye

Question 23

What is the normal clarity/transparency of urine for dog, cat, horse and rabbit

Answer 23

Dog: clear
Feline: slightly cloudy
Horses: cloudy - due to presence of calcium carbonate crystals and mucous
Rabbits - turbid w/ milky appearance due to presence of Ca carbonate crystals

Question 24

What might happen to urine transparency if it sits for awhile?

Answer 24

urine will become more turbid upon sitting due to bact growth and crystal formation
slight foaming is normal in urine but will be inc when protein lvls are elevated

Question 25

What are some important notes about horse urine when it stands for awhile vs fresh

Answer 25

Standing urine will become brown and opaque vs freshly voided is dark yellow and turbid

Question 26

Can dz exist when urine looks normal?

Answer 26

of course! Could have significant dz

Question 27

How do we assess odor for urine?

Answer 27

Male cats, pigs and goats prod strong smelling urine
Odor is often inc when urine is concentrated
often not highly diagnostic test
Strong/ammonia odor: concentrated samples
Little to no odor: dilute samples
Foul odor: may be noted w/ bact growth
Sweet smell: may be indicator of presence of ketones in urine (could smell like acetone or nail polish)

Question 28

What is specific gravity?

Answer 28

Ratio of the density of urine compared to density of distilled water - no units
estimate of ability of kidney tubules to concentrate urine
very useful bc provides valuable info regarding the patient’s hydration status and renal concentrating ability

Question 29

How do we measure specific gravity?

Answer 29

dipstick method NOT accurate so we test separately w/ refractometer
must be performed on the supernatant if the sample is turbid or if it is hard to see the line on the refractometer
affected by temperature - so sample must be at room temp

Question 30

What does hyposthenuria and isosthenuria mean?

Answer 30

A USG below the normal range for that species means that the urine is dilute
Hyposthenuria: USG is btw normal range and isosthenuria range
Isosthenuria: When USG is approaching that of glomerular filtrate (1.008-1.012)

Question 31

What does urine concentration depend on?

Answer 31

water intake, diet, electrolyte balance, age, renal concentrating ability and hydrations status (including fluid administration)
Must look at all aspects of animal to interpret the results, including hydration status, BUN and creatinine lvls
the USG value will fluctuate thruout day and day to day

Question 32

What time of day would we collect urine if we were concerned about animals ability to concentrate urine?

Answer 32

Morning, first pee of the day

Question 33

What is the USG values for dogs, cats, horses and cattles

Answer 33

If they are above these lvls, they are concentrating their urine in acceptable ranges
DOG: >1.030
CAT: > 1.035
HORSE + CATTLE: >1.025