Urinalysis provides important information about renal and lower urinary tract function through evaluation of urine properties such as specific gravity, sediment, biochemical analysis, and culture. Specific gravity measures the kidney's ability to concentrate urine and is assessed through refractometry. Biochemical urine strips can detect substances like glucose, bilirubin, ketones, blood, pH, protein, and nitrites which may indicate underlying conditions. Serum urea and creatinine levels reflect glomerular filtration rate, with elevated levels indicating azotaemia and potentially uraemia.

1. URINALYSIS

2. OVERVIEW
1. Urinalysis
2. Serum/plasma urea & creatinine concentrations
3. Urine protein to creatinine ratio (UPC ratio)
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3. 1.URINALYSIS
MAIN INDICATIONS ARE:
• Evaluation of renal & lower urinary tract abnormalities
• Assessment of some metabolic/endocrine disorders
• Assessment of state of hydration
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4. Gross evaluation
Specific gravity (SG)
Urinalysis
Biochemical analysis
Sediment examination
(microscopy)
Culture 4

5. GROSS EVALUATION: COLOUR
Urine from healthy animals can vary in colour Red discolouration
but is usually light, mild or dark yellow
Red discolouration may indicate haemoglobinuria, myoglobinuria or haematuria. 5

6. GROSS EVALUATION: TURBIDITY
turbidity in urine from
Upper sample :Clear urine Turbid urine a cow with
Lower sample:Turbid (healthy horse) pyelonephritis 6

7. TURBIDITY
 Healthy horses and rabbits may have turbid
urine due to high concentration of mucin and
crystals. In other species turbidity can indicate
the presence of sediment.
 On refrigeration, urine samples may become
turbid from crystallisation of minerals which
were in solution, and they may clear when
returned to room temperature
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8. Gross evaluation
Specific gravity (SG)
Urinalysis
Biochemical analysis
Sediment examination
(microscopy)
Culture 8

9. SPECIFIC GRAVITY (SG)
Ratio of weight (density) of urine to that of an equal volume of water
at the same temperature. No units.
Values depend on:
- hydration status and water intake
- the kidney’s concentrating ability
It is a test of renal tubular function
Hydration status can be determined by assessing skin turgor or by
measurement of serum albumin, or PCV and total proteins. 9

10. SPECIFIC GRAVITY (SG): MEASUREMENT
– Reagent test strips are unreliable for animals/Always use
the refractometer
– If the urine is turbid, centrifuge it before measuring SG of
the supernatant
1.050
1.040
1.030
1.020
1.010
1.000
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11. SG: INTERPRETATION
HYPERSTHENURIA: concentrated urine
- >1.012
-urine of healthy, normally hydrated animals
ISOSTHENURIA: urine neither concentrated nor diluted
-1.007-1.012 (urine SG = plasma filtrate SG)
-persistent isosthenuria warrants further investigation
HYPOSTHENURIA: urine is more diluted than plasma
- <1.007
- persistent hyposthenuria warrants further investigation
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12. SG: INTERPRETATION
* The range of values for SG can vary according to water intake and
hydration status. Usually SG in normal concentrated urine is >1.030
* WATER DEPRIVATION TEST
* Contra-indication: It should never be carried out in depressed,
dehydrated or azotemic animals, or if renal failure is suspected.
* Indication: Confirmation of the animals ability to concentrate its urine
when water is withheld.
* Protocol: The urine SG is monitored every 2 hours until 5% of body
weight is lost, or the urine SG is >1.020.
* Interpretation:
* If the urine SG increases to 1.020, tubular function and ADH availability are
confirmed.
* If the urine SG remains <1.020, diabetes insipidus is suspected.
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13. Gross evaluation
Specific gravity (SG)
Urinalysis
Biochemical analysis
Sediment examination
(microscopy)
Culture 13

14. BIOCHEMICAL ANALYSIS URINE STRIPS
Always follow manufacturer instructions
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15. EXAMPLE OF A URINE STRIP CHART
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16. GLUCOSE
- Glucose is not normally found in urine of healthy animals
- Causes of glycosuria
• Persistent hyperglycaemia
- Diabetes mellitus
• Transient hyperglycaemia
- Stress in cats
- Drugs (xylazine, ketamine)
- IV fluids containing glucose
- Convulsions
• Renal tubular disorders
- Fanconi syndrome
- Primary glucosuria 16

17. BILIRUBIN
– Not accurate for dogs/cats
• Tests utilising a tablet (ictotest) can be more accurate than strip-
tests
• Light can break down bilirubin
– Trace to + normal in healthy dogs.No bilirubin present in
the urine of other healthy animals
– The bilirubin in the urine is water-soluble conjugated
bilirubin
– Causes of bilirubinuria
• Same as causes of bilirubinaemia
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18. KETONES
– Accurate test for animals
• Does not detect β-hydroxybutyric acid
– Ketones are not present in the urine of clinically healthy
animals
• Trace can be normal in rabbits
– Causes of ketonuria
• Diabetes mellitus, pregnancy, starvation, ketosis, immediately after
calving in high–producing dairy cows
N.B. Many disorders causing anorexia in cattle (e.g. mastitis, metritis, pneumonia)
will cause ketonaemia and ketonuria, but levels of ketones are generally not as high
as in primary ketosis.
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19. BLOOD / HAEMOGLOBIN
- Accurate test for animals
- Detects intact RBCs, haemoglobin or myoglobin
- Follow-up positive result with sediment examination
- Interpret positive result in conjunction with the method
of urine collection (cystocentesis can be a cause of presence of
blood in urine)
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20. pH
– Acceptable test for animals
- Carnivores:
• acidic urine is normal if fed a meat diet
• alkaline urine usually reflects urinary tract infection
- Herbivores:
• alkaline urine is normal
• acidic urine may reflect increased protein catabolism
e.g. high protein diet, starvation, fever, nursing animals
– Some drugs can influence pH
– Not an accurate indicator of systemic acid/base balance
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21. PROTEIN
– Acceptable test for animals but can give false positive reaction in
alkaline samples.
– Test detects mainly albumin. Does not detect globulins
– Always interpret in conjunction with SG and sediment examination
(it is not abnormal to have trace protein in concentrated urine but
always abnormal finding in diluted urine).
– Common causes of proteinuria:
• urogenital haemorrhage
• urogenital inflammation
• renal protein loss
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22. NITRITE, UROBILINOGEN, LEUKOCYTES
- Nitrite
• Positive results may indicate bacterial infection
• false negative results occur commonly
- Urobilinogen
• Questionable clinical usefulness
- Leukocytes
• False negative results common in dogs
• False positive results common in cats
NONE ARE RELIABLE IN EXAMINING ANIMAL URINE
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23. 2. Serum urea & creatinine
concentrations
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24. UREA
LIVER
BLOOD
Urea cycle
Urea
TISSUES Urea
NH4+
75%
proteins NH4+ KIDNEYS
25%
Urea
Urea
Dietary Proteins
bacteria NH4+
Urea in
GASTROINTESTINAL TRACT urine
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25. UREA and creatinine
– Glomeruli: 75% of urea is excreted (excretion ↑ or ↓
when glomerular filtration rate ↑ or ↓ )
– Tubules: Urea is reabsorbed (reabsorption ↑ or ↓ when
glomerular filtration rate ↓ or ↑)
– Creatinine is derived from creatine-phosphate,
creatinine is excreted via the glomeruli. It is not
reabsorbed in the tubules so excretion of creatinine is
a measure of glomerular filtration rate.
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26. BUN vs. UREA
– BUN = blood urea nitrogen= concentration of the nitrogen
component of urea in blood
– BUN value is Lower than urea value. BUN:Urea ratio is
approximately 1:2
– But the term BUN is used interchangeably with urea
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27. CREATININE
KIDNEYS
creatine creatinine creatinine
MUSCLE
creatinine
BLOOD
Creatinine in
urine
creatinine NH4+
INTESTINES
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28. AZOTAEMIA
- Increased serum/plasma urea & creatinine
concentrations
URAEMIA
– Marked azotaemia and clinical signs (vomiting,
anorexia, gastrointestinal ulceration)
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29. AZOTAEMIA
CAUSES
PRE-RENAL
RENAL
POST-RENAL
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30. PRE-RENAL AZOTAEMIA
- DECREASED RENAL PERFUSION
- Hypovolaemia, dehydration, cardiovascular disease
 Urea is ↑ and creatinine Normal / ↑
 Urine specific gravity is ↑
- INCREASED UREA PRODUCTION
- G.I. TRACT HAEMORRHAGE
 Urea is ↑ and creatinine is Normal
- HIGH PROTEIN DIET
 Urea is ↑ and creatinine is Normal
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31. RENAL AZOTAEMIA
- RENAL DISEASE
- ONLY evident when more than 60-75% of nephrons
are compromised
• Urea and creatinine are ↑
• Urine is inadequately concentrated
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32. POST-RENAL AZOTAEMIA
- URINARY TRACT OBSTRUCTION
• ureter, urethra
- URINARY TRACT RUPTURE
• ureter, bladder, urethra
- Urea and creatinine are ↑
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33. LOW SERUM/PLASMA UREA: CAUSES
– Decreased Liver Function
– Portosystemic shunt
– Increased Excretion
• Extreme PU/PD
• Overhydration
– Low protein intake
Young Animals have a lower reference range
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34. RUMINANTS / HORSES
- Excrete most of urea via the gut (very little via kidneys). So
blood urea can be normal despite severe renal disease.
- Therefore blood creatinine is a more sensitive indicator of
renal disease
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35. 3.Urine protein to urine
creatinine ratio (UPC ratio)
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36. UPC RATIO
– Used to assess the clinical significance of proteinuria
– Total protein & creatinine concentrations are measured in a single
urine sample and expressed in the same units
UPC RATIO INTERPRETATION
< 1.0 Proteinuria if present is not significant
MILD/MODERATE Significant proteinuria from:
INCREASES (1-2) urogenital haemorrhage
urogenital inflammation
glomerular protein loss
MODERATE/SEVERE Usually glomerular protein loss
INCREASES (>2)
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37. Urine Sediment Examination
 Produced by centrifugation of urine onto a slide
 Looking for:
 Abnormal crystals
 Cells
 Infectious agents
 Casts
 Contaminants
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38. Ammonium biurate: suggestive of liver dysfunction and/or portosystemic shunting
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39. Conjugated bilirubin: normal in dogs, but abnormal in other species. Suggests
conjugated bilirubinemia
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40. Calcium oxalate: suggestive of hypercalciuria, hyperoxaluria (dietary, ethylene
glycol) or calcium oxalate uroliths
Can occur normally if urine has been stored
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41. Magnesium ammonium phosphate (struvite) – present in normal animals but
excessive amounts can be an indicator of struvite uroliths or mixed uroliths
Common in bacterial-induced alkalinuria
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42. Calcium oxalate monohydrate – suggestive of hypercalciuria or EG toxicity
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43. Cysteine – indicative of disruption of cysteine metabolism/catabolism (drug induced
or inborn error in metabolism
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44. Drug-associated - sulfonamides
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45. Tyrosine – associated with severe liver disease
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46. Tyrosine – associated with severe liver disease
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47. RBCs – up to 5 RBC per high power field is normal. Increased RBCs in urine
generally indicates hemorrhage into the bladder or urethra (artifact with catheter
collection in some cases)
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48. WBCs – up to 5 WBC per high power field is normal, higher levels suggest infection
somewhere within the urinary tract
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49. Transitional epithelial cells from renal pelvis, ureters, urinary bladder or urethra
Morphology used for detection of neoplastic change (cytology)
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50. Squamous epithelial cells – indicator of contamination from skin, prepuce etc
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51. Neoplastic cells – commonly transitional cell carcinomas
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52. Bacteria – bacili on the right, cocci on the left. Presence is always abnormal – either
infection or contamination (storage, collection)
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53. Fungi – presence is always abnormal – Candidiasis or Aspergillus sp. In the case of
infection. Be aware: contamination, storage, growth on microscope slides or in stain
preparations
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54. Parasites
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55. Casts:
Hyaline casts = precipitated protein
Cellular casts: These have distinct cells within
the protein matrix - if the cells are of epithelial
origin (i.e., not WBCs or RBCs), they are called
epithelial casts..
Granular casts: As cells within the protein cast
matrix break down, the cast becomes coarsely
then finely granular.
Waxy casts: Waxy casts are the final stage of
cast degeneration (usually originating from
cellular and granular casts). Compared to
hyaline casts, they are readily observable
because they have a smooth appearance, no
internal texture, and are more refractile than the
surrounding urine.
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58. Questions?
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