UNIT 2 - Lecture 3: Urinalysis Flashcards
1
Q
What are 5 instances where a UA is indicated?
A
- New patient (est. baseline)
- Sick patient
- Along with bloodwork
- Monitoring
- Prior to administration of IVF or other treatments
2
Q
What are the 3 methods for urine collection?
A
Free catch/voided, catheterization, cystocentesis
3
Q
What are 3 advantages to a free catch?
A
- Can be easy
- Non-invasive
- Collection during normal voiding poses no risk to patient
4
Q
What are 3 disadvantages to a free catch?
A
- Lower urinary tract contamination
- Manual expression –> discomfort to patient or reflux infected urine into other structures
- Sample not ideal for culture
5
Q
What are 3 advantages to a catheterization?
A
- UB does not need to be distended to obtain sample
- Collection does not depend on patient’s willingness to urinate
- Catheter may be maintained for patient cleanliness, to measure production, or maintain patency in animals with obstruction issues
6
Q
What are 5 disadvantages to catheterization?
A
- Sedation may be necessary
- Difficult to perform with females
- Potential to introduce pathogens
- Urine may be contaminated with cells/bacteria from the urethra
- Small risk of perforation
7
Q
What are 3 advantages of cystocentesis?
A
- Sedation often not necessary
- Preferred sample collection method for culture
- Low risk for iatrogenic infection
8
Q
What are 4 disadvantages of cystocentesis?
A
- Potential for iatrogenic blood contamination
- Potential for inadvertent sampling of other organs
- Small risk of bladder laceration or urine leakage
- Risk of seeding neoplastic cells along needle track from patient with TCC
9
Q
How long should urine be evaluated in house if not refrigerated?
A
Within one hour
10
Q
What can happen if urine is not evaluated within one hour if it is not refrigerated?
A
Cells and casts can decay rapidly and/or crystals may form in vitro
11
Q
What 3 precautions should be taken when sending urine to an outside lab?
A
- Refrigerate/keep cool (don’t freeze)
- Ship fast (overnight or courier)
- Protect from sunlight (bilirubin will break down when exposed to light)
12
Q
What types of tubes should be used to send out a urine sample?
A
Red top (no additive) = chemical analysis, culture
EDTA = cellular examination
13
Q
When would you send out a urine cytology and what sample types should be sent?
A
For evaluation by pathologist to ID bacteria or abnormal cells;
Send both direct and concentrated (sediment) air-dried slides
14
Q
What are the 4 components of a urinalysis?
A
- Gross evaluation (color, clarity, odor)
- USG
- Dipstick (pH, protein, glucose, ketones, blood, bilirubin)
- Sediment analysis
15
Q
How much urine is preferred for a complete analysis?
A
At least 5 ml
16
Q
Normal urine is _____ to _____ in color.
A
Yellow, amber
17
Q
What determines shade and intensity of urine color?
A
Concentration and endogenous pigments (urochromes or urobilin)
18
Q
What does a red urine color mean?
A
RBCs, free Hgb, myoglobin
19
Q
What does a red-brown urine mean?
A
Hematuria, hemoglobinuria, myoglobinuria, methemoglobin
20
Q
What does brown to black urine mean?
A
Methemoglobin from hemoglobin or myoglobin
21
Q
What does yellow-orange urine mean?
A
Bilirubin
22
Q
What does yellow-green or yellow-brown urine mean?
A
Bilirubin or biliverdin
23
Q
What is often the clarity of horse urine and why?
A
Cloudy - calcium carbonate crystals and mucus
24
Q
What does cloudy urine indicate?
A
Presence of cells, crystals, bacteria, casts, sperm, contaminants, and lipid droplets
25
What affects urine odor?
Concentration, diet, meds, bacteria, inflammation, certain medical conditions (i.e. DM)
26
What is USG used for?
To assess kidney's concentrating ability
27
USG is the ratio of a solution's _____ to the _____ of an equal volume of \_\_\_\_\_.
weight, weight, water
28
What instrument is used to evaluate a USG?
refractometer
29
Why should USG be analyzed at room temperature?
Cold urine can cause false increase in USG
30
USG is determined primarily by # of \_\_\_\_\_.
solute particles
31
What electrolytes do urine solutes include?
Na, K, Cl, Ca, P, ammonia
32
What metabolic wastes does USG include?
urea and creatinine
33
Marked proteinuria or glucosuria will very slightly _____ USG.
increase
34
What is the "adequate" USG for a dog in the face of azotemia?
\>1.030
35
What is the "adequate" USG for a cat in the face of azotemia?
\>1.040
36
What is the "adequate" USG for large animals in the face of azotemia?
\>1.025
37
What does adequate USG suggest?
That there are sufficient nephrons to adequately concentrate urine
38
What does inadequate USG in an azotemic animal suggest?
There is a problem that interferes with urine concentrating ability
39
What are 5 problems that can lead to inadequate USG?
1. Insufficient functioning nephrons (kidney disease)
2. Osmotic diuresis
3. Loss of medullary [] gradient
4. Reduced ADH release
5. Impaired response to ADH
40
What tests are unreliable on a dipstick in animals?
USG, leukocytes, urobilinogen, nitrite
41
What tests are useful to evaluate on a dipstick for animals?
Protein, pH, blood, ketones, bilirubin, glucose
42
What is the primary protein detected on a dipstick?
albumin
43
What can cause a false (+) for protein on a dipstick?
Very alkaline urine OR contamination by some cleaning agents
44
Trace to 1+ protein can be found in animals with a _____ urine.
concentrated
45
Urine protein must be interpreted in context with _____ and \_\_\_\_\_.
USG, pH
46
What is sulfosalicyclic acid precipitation (SSA)?
Alternative urine protein assay that can detect Bence Jones proteins
47
How does SSA work?
5% SSA is combined with urine --\> proteins denature --\> cloudy precipitate
48
What are causes for pre-renal (overload) proteinuria?
Hemoglobinuria, myoglobinuria
49
What are causes for renal proteinuria?
Glomerular and/or tubular disease
50
What are causes for post-renal proteinuria?
Hemorrhage, inflammation, trauma, or neoplasia in urinary tract
51
What test is used to assess significance/severity of proteinuria?
UPC (urine protein to creatinine ratio)
52
In health, urine pH is primarily determined by \_\_\_\_\_.
diet
53
Carnivores have _____ protein catabolism --\> more _____ urine (pH???)
increased, acidic, \<7.0
54
Herbivores have _____ protein catabolism --\> more _____ urine (pH???)
decreased, alkaline, \>7.0
55
One would expect a more _____ urine with metabolic acidosis.
acidic
56
One would expect a more _____ urine with metabolic alkalosis.
alkaline
57
What ia paradoxical aciduria?
Metabolic alkalosis with acidic urine
58
Urine is more alkaline with infection with \_\_\_\_\_.
urease-producing bacteria
59
What can lead to a (+) heme/blood reaction in a UA?
Hematuria, hemoglobinuria, myoglobinuria
60
What should a (+) heme result be interpreted with?
urine sediment
61
Free Hgb and myoblobin are \_\_\_\_\_toxic.
nephrotoxic
62
When might RBCs not be seen on urine sediment when there is hematuria?
They may lyse in very alkaline or dilute urine
63
With hematuria, supernantant should be _____ with an _____ pellet after centrifugation.
clear, RBC
64
Hemoglobinuria is "spill-over" from excess free Hgb in \_\_\_\_\_.
plasma
65
When is the only time hemoglobinuria occurs?
With extravascular hemolysis
66
What erythrogram finding should you expect with hemoglobinuria? What should the plasma look like?
Anemia with red plasma
67
What are some medical causes for hemoglobinuria?
1. IMHA
2. Oxidative damage
3. RBC parasites
4. Severe hypophosphatemia
68
How can you differentiate hematuria from hemoglobinuria on urine sediment?
Hemoglobinura = no RBCs noted on sediment
69
When is myoglobin released into the plasma?
When where is severe skeletal muscle injury
70
What colors can be expected in urine with myoglobinuria?
Orange, red, or brown
71
How can myoglobinuria be differentiated from hematuria on erythrogram and urine sediment?
No anemia; No RBCs present on sediment
72
With myoglobinuria, a very high _____ activity is expected (leaked enzyme released from injured myocytes).
creatine kinase
73
What are some DDx for myoglobinuria?
1. Severe muscle injury
2. Exertional rhabdomyolysis (horses)
3. Inherited myopathies
74
What ketone bodies can be released into the urine?
Acetone, acetoacetate, and ß-hydroxybutyrate
75
What are 2 general situations in which ketone bodies are produced?
1. Starvation
2. Inability to utilize carbs as an alternate energy source
76
What are some diseases in which ketones may be present in the urine?
1. Unregulated DM in dogs and cats
2. Pregnancy toxemia in sheep and camelids
3. Ketosis in cattle
77
Ketonuria precedes \_\_\_\_\_.
ketonemia
78
When is a false (+) for ketonuria possible?
With highly pigmented urine
79
What are the 4 steps to ketone production?
1. Energy production shifts from utilization of carbs to lipids due to DM, starvation, or hypoglycemic disorders
2. Excessive β-oxidation of fatty acids in hepatocytes --\> more acetyl-coA than needed for gluconeogenesis and triglyceride synthesis
3. Excess acetyl-coA stimulates ketogenesis by liver --\> increased formation of ketoacids --\> ketonemia
4. Ketones in blood excreted in urine --\> ketonuria
80
Ketogenesis is stimulated by _____ and repressed by \_\_\_\_\_.
glucagon, insulin
81
What is ketosis?
Pathologic state caused by excessive ketogenesis
82
What is ketoacidosis?
Ketosis with concurrent acidemia
83
Prolonged ketonuria may result in depletion of _____ or _____ since renal excretion of ketones (anions) obligates excretion of \_\_\_\_\_.
sodium, potassium, cations
84
T/F: Ketonuria is an indicator of kidney disease
False: It indicates a systemic problem, NOT kidney disease
85
What does a (+) bilirubin reaction indicate?
Presence of conjugated bilirubin in urine (soluble form)
86
Bilirubinuria occurs secondary to _____ from _____ disease or _____ disease.
hyperbilirubinemia, liver, hemolytic
87
Bilirubin should not be detected in urine other than in what 2 situations?
concentrated canine and ferret urine (low renal threshold)
88
What values on a dipstick mean urine is (-) for glucose?
\<100 mg/dL
89
What is the renal threshold for glucose in dogs? Cats? Horses? Cows?
Dogs = 180 mg/dL
Cats = 280 mg/dL
Horses = 160 mg/dL
Cow = 100 mg/dL
90
What is the most common cause of glucosuria?
Hyperglycemic glucosuria
91
What are reasons for persistent hyperglycemic glycosuria?
DM, Cushings, acromegaly, pheochromocytoma
92
What is a reason for transient hyperglucemic glucosuria?
Stress/excitement (esp in cats)
93
What are reasons for normoglycemic glycosuria?
Renal tubular defects - acquired or inherited damage to tubular epithelium
94
What are examples of acquired renal tubular defects that lead to normoglycemic glucosuria?
Gentamycin toxicity, leptospirosis
95
How is urine sediment prepared?
1. Centrifuge urine
2. Remove most of supernatent
3. Gently re-suspend the sediment in the remaining supernatent
4. Examine a wet mount without stain
5. Lower microscope condenser for optimal viewing
6. Report # cells or crystals per low or high power field
96
What do RBCs look like on a wet mount?
Lack internal structure
97
How many RBCs can be seen in urine of healthy animals?
\<5 RBCs/hpf
98
What do WBCs look like on a urine wet mount?
Round, granular cells with internal structure (1.5 to 2x diameter of RBCs)
**\*arrowheads in pic\***
99
How many WBCs can be seen in urine in health?
\<5 WBCs/hpf
100
What is the term for increased #s of WBCs in urine?
pyuria
101
What epithelial cells can be seen in urine?
Transitional, squamous, renal tubular, neoplastic
102
When are epithelial cells in the urine a concern?
When they are atypical or in casts
103
\_\_\_\_\_ epis are common in voided urine - are _____ for lower urogenital tract.
Squamous, contaminants
104
What sample type should not have bacteria in the urine?
cysto
105
What are casts?
Cylindrical aggregates of materials that collect in the renal tubules and collecting ducts;
Are named and classified according to composition
106
What does appearance of casts depend on?
Length of time in tubule
107
What do hyaline casts contain and what #s are seen in healthy patients?
Contain Tamm-Horsfall mucoprotein +/- other proteins;
\<2/lpf
108
When are hyaline casts seen in increased #s?
Fever, exercise, passive congestion, protein-losing glomerular disease
109
What is a cellular cast the result of?
Ischemia, infarction, or nephrotoxicity --\> degeneration or necrosis of tubular epithelial cells
110
Presence of cellular casts indicates \_\_\_\_\_, but not _____ or \_\_\_\_\_.
acute tubular injury, extent, reversibility
111
What are granular casts?
Degenerated cellular casts
112
T/F: Granular casts can be present in low #s in animals without apparent tubular injury.
True
113
When do RBC casts form?
When there is intra-renal hemorrhage.
114
What is a waxy cast and what does it indicate?
Final stage of cast degeneration; indicates tubular injury.
115
When is presence of a waxy cast of pathological significance?
Always
116
How are waxy casts differentiated from hyaline casts?
Waxy casts have squared off ends
117
Lack of crystalluria does not exclude the possibility of \_\_\_\_\_.
urolithiasis
118
Presence of crystalluria does not mean there is \_\_\_\_\_.
urolithiasis
119
What are the 5 common crystals?
1. Struvite
2. Bilirubin
3. Calcium carbonate
4. Amorphous
5. Calcium oxalate dihydrate
120
What are the 4 uncommon crystals?
1. Calcium oxalate monohydrate
2. Ammonium biurate
3. Cystine
4. Drug-associated
121
What are two other names for struvite crystals?
Magnesium ammonium phosphate
OR
Triple phosphate
122
What do struvite crystals look like?
Have "coffin lid" or "prism" appearance
123
Struvite is the most common type of crystal in _____ and \_\_\_\_\_.
dogs, cats
124
What type of urine do struvite crystals favor?
alkaline
125
Struvite crystals are often associated with _____ with _____ bacteria by _____ pH and increasing \_\_\_\_\_.
cystitis, urease-producing, raising, free amonia
126
What do bilirubin crystals look like?
Needle-like to granular, yellow, often small crystals
127
What spp are bilirubin crystals common in and what is the clinical significance?
Dogs; no clinical significance
128
What do calcium carbonate crystals look like?
Variably-sized, frequently appear as large spheroids with radial striations.
129
What color can the urine be when there are high #s of calcium carbonate crystals present?
Can have a brownish tinge
130
What spp are calcium carbonate crystals normally found in (in the urine)?
Horses, rabbits, guinea pigs, goats
131
What can make up amorphous crystals?
Urates, phosphates, xanthine
132
What color and pH can amorphous urates make the urine? Amorphous phosphates?
Urates = yellow or yellow-brown; acidic
Phosphates = lack color; alkaline
133
Can specific clinical interpretations be made based on the finding of amorphous crystals?
No
134
What do calcium oxalate dihydrate crystals look like?
Colorless squares with "X" of variable size
135
What pH does calcium oxalate dihydrate crystals favor?
Any
136
What do calcium oxalate monohydrate crystals look like and what do they indicate?
Vary in size, may have a spindle, oval, or dumbbell shape;
Indicate supersaturation of urine with calcium and oxalate
137
What spp commonly has calcium oxalate monohydrate crystals in their urine in health?
Horses
138
What is presence of calcium oxalate monohydrate crystals associated with in dogs and cats?
Ethylene glycol intoxication
139
What do ammonium biurate crystals look like and what type of urine do they favor?
Brown or yellow-brown spherical bodies with irregular protrusions;
Favor neutral to acidic urine
140
What conditions are ammonium biurate crystals commonly seen with?
In dogs and cats with congenital or acquired portal vascular anomalies (i.e. PSS), +/- ammonium urate uroliths
141
What breeds are predisposed to urate urolithiasis?
Dalmatians and Bulldogs
142
What do cystine crystals look like and what type of urine do they favor?
Flat colorless plates, hexagonal shape with equal or unequal sides;
Favor acidic urine
143
What does cystinuria result from?
Inborn error of metabolism involving defective renal tubular reabsorption of certain amino acids including cysteine.
144
Cystine crystals are almost exclusively found in \_\_\_\_\_.
male dogs
145
Other than crystals and blood, etc., what are some etiologic agents that can be found in urine sediment?
Fungal hyphae, parasites, bacteria, TCC
