urinalysis Flashcards
filtrate? Why is the amount of urine produced each day so much smaller than the amount of filtrate?
Filtrate is the water and dissolved substances filtered out of the plasma by the glomerulus; substances that the body can still use are reabsorbed by the body.
What are the main waste products found in urine? What two substances are not found in the urine of healthy pets?
urea and creatinine; protein and glucose
What would happen to the cells of the body if the kidney didn’t balance the amount of salt and water through excretion or conservation of these elements?
Too much retained salt or too little plasma causes the cells to dehydrate and shrink; too little salt or too much water leads to cells absorbing extra water swelling and perhaps bursting
How does kidney function relate to blood pressure?
When the arterial blood pressure drops for any reason re-absorption of water by the kidney is increased causing concentrated urine
How does the kidney maintain the normal pH in the body?
The kidney selectively excretes acids and prevents the loss of bases
uremia
It is when kidney function is impaired and nitrogen-containing wastes (urea, uric acid, creatinine) accumulate in the blood
erythropoetin? How is kidney function related to anemia?
causes the bone marrow to make RBCs; Since erythropoietin is produced by the kidneys if the kidney function is impaired RBC formation will be reduced causing anemia
What is the difference between the ureter and the urethra (what do they connect to anatomically)?
The ureter carries urine from the kidney to the bladder; the urethra carries urine from the bladder to outside the body
What types of containers are appropriate for collecting urine samples for analysis?
Clean containers with no soap residue
If urinalysis cannot be performed within 30 minutes, how should urine be stored for exam later that day?
In the refrigerator in a sealed opaque container
If you stored the urine properly, what do you need to remember before you do the testing later that day?
Let the urine come to room temperature before testing
5 things that should be included when labeling a container of urine
- patient/client name
- date and time of collection
- method of urine collection
- contents (“urine”)
- If any preservative was added to the sample, the name of the preservative should be included
When collecting a sample during normal voiding, should you place the container under the animal before it starts to urinate?
The first urine which is voided should not be collected to minimize contamination with cells or debris from the distal portion of the urethra. Wait until the stream starts them start collecting
What are two advantages and two disadvantages of collecting urine by “free catch”?
Advantages:
- sample may be collected by clients
- there is no risk of infection or trauma to the patient
Disadvantages:
- sample may be contaminated
- the animal may not urinate when the sample is needed
Describe how manual expression of the bladder is done
Moderate pressure is exerted on the bladder, Steady pressure should be applied, Pressure should be maintained until the urethral sphincters relax and urine is expelled
advantages and disadvantages of manual expression
Advantages:
- there is minimal risk involved in introducing bacteria into the urinary tract
- Urine samples may be collected at the convenience of the clinician
Disadvantages:
- the bladder may be traumatized or rupture due to excess pressure
- The bladder may not contain an adequate amount of urine to perform this procedure
- Urination is difficult to induce in most conscious patients
- Urine may be forced back into the ureters and kidneys if excess pressure is used
What are two advantages and 2 disadvantages of the catheterization method?
Advantages:
- samples can be obtained directly from the bladder for culture with little risk of contamination if aseptic technique is followed
- The samples can be obtained at the convenience of the veterinarian
- The catheter can be attached to a collection bag in order to accurately monitor the quantity of urine produced
Disadvantages:
- trauma to the urethra may result in complications for the patient as well as creating a false hematuria
- Bacteria can be introduced into the bladder and urethra through the use of poor technique
cystocentesis
A small gauge needle (23 g, 1 1⁄2”) is attached to a new syringe. Careful placement of the needle in the bladder is important. Tranquilization/anesthesia is usually not required for this procedure
What is a disadvantage that may complicate interpretation of the urinalysis with cystocentesis?
There may be blood in the sample from the procedure if a blood vessel is penetrated by the needle.
Which method of collection is preferred if a culture and sensitivity test will be done?
cystocentesis
Why is collecting urine the first thing in the morning best?
sample is more concentrated
Can urine be frozen for later analysis?
no
Name 2 chemicals used to preserve urine
formalin, thymol, mucolexx
What do you have to do before adding preservative?
chemical and physical test
In a clinic, what is the only time you need to use a chemical preservative?
If urine cannot be tested within 4 hours-sending out to a lab
Name 3 things/categories that are always assessed on the physical exam of urine and 1 that is occasionally done
always: Specific Gravity, Color, Turbidity
occasionally: monitoring urine output for volume
What is specific gravity of urine a measure of?
the density of urine compared to pure water
What is the SG of distilled water?
1.000
What 2 instruments may be used to determine SG?
Urinometer and refractometer
What 4 factors will affect the SG of urine in a healthy animal?
Activity, Fluid intake, Diet, Climate
Concentrated urine will have which—a high SG or a low SG? What about dilute urine?
higher; lower
What is the SG when the urine is isosthenuric?
1.008-1.012
What is the significance of isosthenuria?
Kidneys are neither concentrating nor diluting the urine. This may not indicate renal disease unless it persists in the face of dehydration or over-hydration. Persistant isothenuria is present in complete kidney failure.
If a pet has a urine SG of 1.010 today, does that mean for sure that the kidney is not functioning?
No, All specific gravity values should be evaluated with other clinical and physical symptoms
A dipstick test shows a trace of protein. Is there a greater cause for concern if the SG was low or if it was high?
If it was low
How many decimal places should be used when recording SG?
3
Besides species, what are 5 other things that influence the volume of urine an animal produces?
body weight
diet
fluid intake
physical activity
temperature and humidity
List 3 methods of monitoring daily urine production in animals
- Metabolism cage
- indwelling urinary catheter connected to a collection bag
- weighing bedding dry and then after urination
If an animal has polyuria, would the SG be high or low?
High urine volumes are associated with dilute (low SG) urine which is very light yellow to clear in color
Name 7 terms used in recording the color of urine and what each indicates
Colorless=Low SG. Very dilute. May be normal if fluid intake is excessive or abnormal if the kidney is unable to concentrate urine due to disease
LightYellow=Low SG. Dilute. Normal. High fluid intake
Medium Yellow=Normal
Amber=High SG. Highly concentrated. A dark yellow that is almost orange. Normal. Fluid intake has been low.
Red(lightordark)= Hematuria, Hemaglobinuria, or both. Microscopicexamis required to determine cause. Hematuria will sometimes cause cloudiness, where pure hemaglobinuria will not.
Red/Brown or Brown=Hemaglobinuria or myoglobinuria. As urine ages in the lab or bladder, these pigments become brown. Normal horse urine will become brown as it stands.
Yellow/Green=A light green color. Caused by bilirubin or biliverdin.
Blue/Green=Caused by dyes, chlorophyll, and pseudomonas bacteria
What are the 3 terms used in recording the turbidity of urine? Which 2 can be used together?
clear, cloudy, flocculent; cloudy and flocculent
What can cause urine to be cloudy?
Milky or hazy due to large amounts of microscopic crystals or cells
difference between cloudy and flocculent
Flocculence is floating flecks of material visible when urine is mixed. Flecks are larger than the particles that cause cloudiness and can be seen individually with the naked eye
What can cause variation in the pH of urine?
Urine from animals suffering from bacterial cystitis or contaminated urine that is allowed to stand at room temperature may become more alkaline because of bacterial action
Name 4 factors that will lead to acid urine
- normal in carnivorous animals
- nursing calves and foals
- diet with an excess of protein
- starvation (catabolism of protein)
- fever
- metabolic acidosis
- prolonged muscular activity
Name 4 factors that will lead to alkaline urine
- normal in herbivorous animals
- vegetable diets
- bacterial decomposition of urine (from disease or from sample contamination)
- urine retention: decomposition of urea, alkalosis, at room temperature urea decomposes to form ammonia which is alkaline
What change in pH happens if urine is not preserved properly? What causes this?
urine that is allowed to stand at room temperature may become more alkaline because of bacterial action
What number represents a neutral, acid, and alkaline pH?
acid < 7 < alkaline
Dog, horse, Cat, Bull, Sheep, Pig, Elephant, Seal
acid 6-7
alkaline 8
acid 6-7
alkaline 7.4-8.4
alkaline
alkaline or acidic
alkaline
acidic
Which protein do dipsticks test for? Is a normal result positive or negative?
albumin; negative
Glucose in the urine indicates what condition maybe affecting the animal?
Hyperglycemia and possible diabetes
Ketones are produced as a result of the breakdown of ____?
fat
Name 2 patient conditions that can result in ketosis
- pregnant or lactating cows or ewes
- starvation or fasting - body is primarily metabolizing fat, acidosis, diabetes (body is unable to use glucose for energy, so it breaks down fat.)
Bilirubin in the urine might indicate disease affecting which organ?
liver
What is the difference between hematuria and hemoglobinuria? What causes each?
Hematuria - intact RBC in the urine
Hemoglobinuria - hemoglobin in the urine due to excessive hemolysis of RBCs
What causes myoglobinuria?
myoglobin from degenerating muscle cells will cause a positive reaction if a high level is reached
A large number of WBCs in the urine indicates what? What is the medical term for this?
The presence of WBCs in the urine indicates a bacterial or fungal infection of the bladder or kidney
What are the things we look for in urine sediment? Which are large enough to see under low power?
Important structures to identify in urine sediment include: casts, erythrocytes, leukocytes, bacteria, epithelial cells, crystals; Casts
Explain why it is important to standardize the procedure used to make and examine urine sediment? Which things must always be done the same way?
Staining the sediment to facilitate identification of the formed elements is optional. This step should also be standardized, however. Either it should always be done (using the same amount of stain each time) or never be done
Why is it important to examine urine sediment as soon as possible after urine collection? What changes will occur if the urine is allowed to stand?
Casts, WBC and RBCs tend to dissolve or lyse and dissappear when the urine is allowed to stand
Describe the procedure used to prepare unstained sediment. Include times, amounts, speed
(?)
small drop on slide
apply coverslip
examine
- 10 mL of solution, centrifuge at 1500 rpm for 5 minutes
Describe the procedure for examining the sediment and reporting the results.
Which objectives do you use?
What elements are quantified under each power?
How many fields are checked?
Where are those fields located on the slide?
10X and 40X; Casts & crystals under 10X, Cells and bacteria under 40X; 10 for 10X, 8 for 40X; Edges for casts and crystals, entire slide for the cells and bacteria
What happens to RBCs in dilute urine? Strongly alkaline urine?
Crenated; Lyse or dissolve
If there are so many RBCs that you can’t see anything else, how can you get rid of them? What affect will doing this have on the appearance of WBCs? Dipstick results?
Acetic acid; none; none
Are RBCs in the urine always a result of bleeding into the urinary system?
Yes unless contaminated by female in heat
Name 2 ways hemoglobin can get in the urine. How might the plasma color help you decide which of these happened?
Blood in urine, proteinuria; hemolyzed (red)
What do WBCs in fresh urine look like? How much bigger are they than RBCs? How does their size compare to transitional epithelials?
Granular; 2-3X; Transitionals are 3X the size of a WBC
Are WBCs normally present in urine?
very few 2-3/hpf
What is the effect of alkaline or dilute urine on the appearance of WBCs (2 things)
can lyse or dissolve
What do squamous epithelials look like (size, shape, nucleus) and where do they come from?
Derived from the distal urethra, vagina, vulva, or prepuce, Not considered significant; Flat, thin cells with homogeneous appearance, Largest cells in urine, Straight edges with distinct corners
What do transitional epithelials look like (size, shape, nucleus) and where do they come from?
From bladder, ureters, renal pelvis, and proximal urethra; Come in various rounded shapes, Outline is smooth, Intermediate in size between the squamous epithelial cell and the renal cell, Usually more than 3-4 times the size of WBCs, Granular appearance, similar to WBCs. Small nucleus may not be visible.
Describe the appearance of renal and renal caudate epithelial cells. (size, shape, nucleus)
Renal: Smallest epithelial cell, Originate in renal tubules, Often confused with WBCs, Generally round and contain a large nucleus with nongranular cytoplasm
Renal Caudate: Cell similar in size and appearance to the renal cell, but has a “tail”, Come from the renal pelvis inside the kidney
Where are casts formed? What are they made of?
Formed in the lumen of the distal and collecting tubules of the kidney; Secreted protein precipitates in acidic conditions and forms casts shaped like the tubules
Describe the basic shape of casts
Cylindrical structures with parallel sides, Width determined by the width of the lumen in which they are formed, Ends may be tapered, irregular, or round, Any cells or structures may be incorporated into casts
What is the significance of finding a bunch of casts?
Larger numbers can indicate a lesion in the renal tubles
Which type of cast is nearly colorless and made up only of protein?
hyaline
Describe how you can distinguish between cellular casts and granular casts?
Granular have small granules, cellular will have larger cells
List 5 types of casts
Hyaline, granular, epithelial, RBC, WBC, fatty, waxy
What are round bacteria called? What are rod-shaped of bacteria called? How do you track bacteria numbers when doing the microscopic exam?
Cocci; Bacilli; None, few, many
Is bacteria in urine always significant?
Depends on method of collection and sample handling/container:
voided sample - when no possible contamination
catheterization or cystocentesis - yes
Why should you always discard the first few ml of urine collected by catheterization and not collect the first few mls during normal urination?
To decrease contamination
Besides your results, the date, the patient, name and your name, what 2 things are also important to include on your lab report for a UA?
Method and time of collection, if preservative added
What 3 factors can affect what crystals you see or if you see any crystals in a sample?
ph
concentration of urine
sample handling
Name 3 crystals that are primarily seen in acid urine and 3 that are primarily seen in alkaline urine.
Acidic-Calcium Oxalate, amorphous urates, bilirubin
Alkaline-Struvite (MAP), amorphous phosphates, calcium carbonate
Which type of crystal can be seen in large quantities in healthy horses and rabbits?
calcium carbonate
amorphous
granular precipitate
Crystals can be an indicator of what problem(s)
May or may not be clinically significant, - Crystals form as a result of elements being secreted by normal renal activity. - Some crystals are indicative of metabolic disease
Describe the appearance of fat droplets in a urine sediment; how are they different from cocci?
Lightly green-tinged, highly refractile spheres; Will rise to surface if set for few moments, Different plane of focus
Describe the shape of MAP, Calcium Oxylate, Bilirubin, and Calcium Carbonate crystals.
MAP (struvite) coffin shaped
Calcium Oxylate-back of envelope
bilirubin- spikes
Calcium carbonate-dumbell shaped
What animals may normally have some fat in their urine?
Cats-obesity, diabetes mellitus, hypothyroidism, and high-fat meals
What cells may yeast be confused with? Is yeast more likely to be from infection or contamination?
Fat droplets; contamination
What is one parasite ova you might see in urine? What does it look like?
Pearsonema plica—bladder worm, looks like a whipworm ova
What is the significance of sperm in the sample?
intact male could cause increased
protein level in urine
equine normals
PCV: 42%
g/dl: 6-7.5
WBC/ul: 9000
seg: 50
lymph: 42
platelet: 8-30 oif
bovine normals
PCV: 35%
g/dl: 7-8.5
WBC/ul: 8000
seg: 30
lymph: 60
platelet: 8-30 oif
SG of dog
1.025 (1.001-1.065)
SG of cat
1.030 (1.001-1.080)
casts when first come from tubules
gelatin like
bacteria is mainly from what if found in urine
by a contaminated stain
not an error of physical UA
urine dripped on dipstick instead of dipping
crystals reporting
quantified by type using “+”
correct reporting for bacteria
++ bacteria
preparing urine for chemical UA
sediment is remixed with 0.5 ml of supernatant
WBCs in urine
2-3 X RBC in size
round and granular
