Urine collection, processing and physical examination

Question 1

Specimen Storage and Handling for urine

Answer 1

Diagnostic tests are of little value if the sample has not been collected or stored properly
It can lead to an incorrect diagnosis and treatment, or a condition can be missed completely

Question 2

Appropriate urine containers

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, leak-proof and inexpensive
If storage or shipment is required, a tight-fitting lid is essential

Question 3

4 ways to collect urine

Answer 3

Natural micturition (aka free catch)
Manual expression (still considered to be free catch)
Catheterization
Cystocentesis

Question 4

Sample preservation

Answer 4

Urine is considered unstable so should be looked at as soon as possible (within 30-60 minutes)
The longer the sample sits at room temperature, the more alkaline the sample will become
Record when the sample was collected and when it was analysed

Question 5

When to refrigerate urine

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
Refrigeration is the most common form of short-term storage and preservation–can be used for up to 12 hours after collection

Question 6

What to do once a urine sample has been refrigerated

Answer 6

Samples need to be warmed to room temperature before analysis
USG will be increased if the urine is cold Enzyme- based reactions are decreased if the urine is cold
Crystals can form in refrigerated samples–may not dissolve when the urine is brought to room temperature
Abnormalities found on stored samples should be retested on a fresh sample

Question 7

Samples that require storage for more than 12 hours can be preserved by adding one of the following:

Answer 7

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

Question 8

Physical Examination of Urine should include

Answer 8

Before the chemical tests or a microscopic evaluation is performed, the physical properties of the urine should be noted. These include:
Urine Volume
Color
Clarity/Transparency
Odor
Specific Gravity

Question 9

How to measure urine volume

Answer 9

Owner often provides this information
May mistake pollakiuria for polyuria
Taking an accurate history will aid in differentiating between the two

Question 10

Urine production is influenced by several variables including:

Answer 10

Species
Body weight and size
Diet
Fluid intake
Physical activity
Environmental factors such as temperature and humidity

Question 11

Polyuria is

Answer 11

The formation & elimination of excessive amounts of dilute urine
Often accompanied by polydipsia
Polyuria in the presence of dehydration occurs when the 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 12

What are the two types of polyuria

Answer 12

Pathological
Physiological

Question 13

Pathological polyuria is caused by

Answer 13

Occurs with many disease conditions including diabetes insipidus, diabetes mellitus, CRF, ARF, nephritis, pyometra, hepatic disorders

Question 14

Physiological polyuria is caused by

Answer 14

Due to high fluid intake, high salt intake, fluid therapy, or medications (steroids and diuretics)

Question 15

Oliguria is

Answer 15

Decreased urine formation by the kidneys and/or decreased elimination of urine from the body

Question 16

Oliguria is caused by and treated by

Answer 16

Can be physiological as a result of:
Decreased water consumption
Exposure to a warm environment
May be a response to dehydration, fever, vomiting…
The situation results in a small volume of urine that is usually very concentrated
It is reversible if the primary problem is corrected

Question 17

Colour of urine

Answer 17

Normal urine colour varies from nearly colourless to a deep amber
The color of the urine is usually related to the degree of urinary concentration
Though it may also be due to the presence of abnormal constituents within the sample
An animal’s first urination of the day is usually the most concentrated sample of the day, and therefore the darkest in color
You must report urine colour as part of the urinalysis
A number of conditions result in a change the color of urine
Evaluate urine color by placing the sample in front of a white background

Question 18

Red or red-brown urine means

Answer 18

Most often due to hematuria or hemoglobinuria
Fresh hemorrhage of the urinary tract
Must confirm presence of RBCs with microscopic exam
Proteinuria accompanies this colour change

Question 19

Brown or brown-tinged urine means

Answer 19

Myoglobinuria
Proteinuria accompanies this colour change on the chemical analysis of the urine

Question 20

Yellow-brown/green colour urine is caused by

Answer 20

Produces a greenish-yellow foam when shaken
Usually due to bilirubinuria
Due to liver disease, hemolysis or the presence of bile
Bilirubin is usually confirmed by microscopic or chemical means

Question 21

What can drugs in urine look like for colour

Answer 21

Can produce variations in colour from pink to green or blue
Therefore, an adequate history must be taken

Question 22

Clarity/Transparency is determined by

Answer 22

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 increase in turbidity may be caused by the presence of mucus, cells, vaginal secretions, sperm, crystals, bacteria, fat, calcium compounds, fecal and other contaminants
The underlying cause is determined by microscopic examination of the urine

Question 23

How does urine clarity change by species

Answer 23

rom species to species
Canine–normally clear
Feline- normally slightly cloudy
Horses– normally cloudy
Due to the presence of calcium carbonate crystals and mucous
Rabbits-normally turbid with a milky appearance
Due to the presence of calcium carbonate crystals

Question 24

How to tell transparency of urine

Answer 24

When evaluating transparency, it may be easiest to do so by placing a sheet of paper with lettering behind the sample to evaluate the urine

Question 25

Turbid/flocculent urine looks like

Answer 25

Turbid/Flocculent–cannot see through the sample, suspended particles are present in the sample and may be visible with the naked eye
Urine will become more turbid upon sitting due to bacterial growth and crystal formation
Slight foaming is normal in urine but will be increased when urine protein levels are elevated

Question 26

What does cloudy urine look like before and after centrifuge

Answer 26

cannot read through the sample, objects are blurred, sample usually contains large particles
Significant amount of sediment is present after centrifugation

Question 27

What does horse urine look like after sitting

Answer 27

Horse urine will become brown and opaque upon standing while freshly voided urine is dark yellow and turbid

Question 28

Odour of urine

Answer 28

Male cats, pigs and goats produce strong smelling urine
Odor is often increased when urine is concentrated
Often not a highly diagnostic test

Question 29

What can the smell of urine tell you

Answer 29

Strong/ammonia odor: concentrated samples
Little to no odor: dilute samples
Foul odor: may be noted with bacterial growth
Sweet smell: may be an indicator of the presence of ketones in the urine

Question 30

Specific gravity is

Answer 30

It is the ratio of the density of urine compared to the density of distilled water
Because it is a ratio, there are no units
It is an estimate of the ability of the kidney tubules to concentrate urine

Question 31

why do we test urine SG

Answer 31

Provides valuable information regarding the patient’s hydration status and renal concentrating ability

Question 32

How to test urine SG

Answer 32

Dipstick method is NOT accurate so we test separately with a 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 temperature
Normal values for urine specific gravity vary between species

Question 33

What does the urine Sg tell u

Answer 33

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

Question 34

What is SG dependent on

Answer 34

Urine concentration depends upon water intake, diet, electrolyte balance, age, renal concentrating ability and hydration state (including fluid administration)
Must look at all aspects of the animal to interpret the results, including hydration status, BUN and creatinine levels
The USG value will fluctuate throughout the day and from day to day

Question 35

USG dog

Answer 35

> 1.030

Question 36

USG cat

Answer 36

> 1.035

Question 37

USG horse

Answer 37

> 1.025

Question 38

USG of cattle

Answer 38

> 1.025