Urinalysis Flashcards
What are you looking at during gross urine examination?
Volume, turbidity and colour
What is the colour difference between blood and haemoglobin in urine?
Blood = red/cloudy
Haemoglobin = red/brown
What should you always interpret USG alongside?
Hydration status
Q
What time of day is best to collect urine for analysis?
Morning - urine is most concentrated (need multiple morning samples to accurately find abnormalities)
Which USG results count as hyposthenuria?
<1.008 - kidneys are actively diluting
Name as many differentials for hyposthenuria as you can
Hyperadrenocorticism (decreased ADH)
Hypercalcaemia (decreased ADH and NaCl reabsorption)
Hepatic disease (decreased urea)
Pyelonephritis (decreased ADH sensitivity)
Diabetes insipidus (decreased ADH)
Pyometra (decreased ADH sensitivity)
Hyperthyroidism (increased GFR)
Psychogenic polydipsia
IV fluids
Diuretics
Normal depending on hydration
What USG readings will you see with renal disease?
Isosthenuria - 1.008-1.013
Is a USG of 1.020 appropriate in a dehydrated dog?
No - this is minimally concentrated urine (1.014-1.029 USG)
In what 3 situations is a USG of over 1.030 seen?
Dehydration
Normal
Acute kidney injury
Which disease results in a USG of 1.014-1.029 due to decreased aldosterone?
Hypoadrenocorticism - decreased aldosterone results in decreased NaCl reabsorption = minimally concentrated urine
What USG range would you expect to see in diabetes mellitus?
1.014-1.028 minimally concentrated urine
Which conditions result in an increased urine pH?
Alkalosis
Urinary tract infection
Urinary retention
Which 5 conditions result in acidic urine?
Fever
Starvation
High-protein diet
Acidosis
Excessive muscular activity
Is a small amount of protein in urine ever ok?
Yes, if in concentrated urine (1+ with >1.030 or 2+ >1.040)
What are the 4 broad causes of proteinuria?
Haemorrhage
Urinary tract inflammation
Kidney disease
Pre-renal proteinuria
If a cat has a blood glucose of 17mmol/L, will glucose be seen in the urine?
Yes - glucose present in urine if it exceeds the renal reabsorption capacity, which is >15mmol/L in cats
If a dog has a blood glucose of 8mmol/L, will it have glucose in it’s urine?
No - glucose present in urine if it exceeds the renal reabsorption capacity, which is >10mmol/L in dogs
In which syndrome do you see glucosuria without hyperglycaemia?
Fanconi Syndrome - due to renal tubular pathology
Is glucosuria seen in hyper or hypoadrenocorticism?
Hyperadrenocorticism
What do the following conditions have in common?
- Starvation/Anorexia
- High-fat diet
- Diabetes mellitus/Ketoacidosis
- Very young animals
Ketonuria - see this before ketonaemia
True or False?
Hyperbilirubinaemia is seen before bilirubinuria
False - bilirubinuria is seen first
Small amount of bilirubin in concentrated urine is ok in dogs, but even trace amounts are significant in cats
What are the 2 main causes of bilirubinuria?
Hepatobiliary disease - cholestatsis or hepatic disease
Haemolysis - haemolytic anaemia
How long can urine be stored for before testing?
Refrigerated for up to 12 hours
Which method of urine sampling is best for urinalysis?
Cystocentesis
How can you differentiate for certain between blood, myoglobin and haemoglobin in the urine?
Centrifuge
Haematuria = red blood cell pellet with clear supernate
Haemoglobinuria = no red blood cell pellet, red/brown supernate and serum shows haemolysis and anaemia
Myoglobinuria = no red blood cell pellet, red/brown supernate and serum is clear with no anaemia
What process is useful for sediment examination?
Slow centrifugation over a longer period of time
How can you rule out bacterial infection from urinalysis?
Culture - lack of haematuria, pyuria or proteinuria doesn’t rule out infection
Are urine casts increased or decreased in acidic urine?
Increased
Decreased in alkaline urine as dissolve
How does urine pH, concentration and temperature affect urinary crystals?
Changes the type of urinary casts produced
Struvite, monohydrate, calcium oxalate, dihydrate, ammonium biurate, urate and cysteine casts
Give the 5 differentials for physiologic/benign proteinuria
Exercise
Seizuring
Fever
Extreme temperatuew
Stress
UP/C normally <0.5
Is congestive heart failure a differential for pre-renal, renal or post-renal proteinuria?
Pre-renal
Do parenchymal inflammation and tubular/glomerular proteinuria result in pre-renal, renal or post-renal proteinuria?
Renal
Give the 2 main differentials for post-renal proteinuria
Urinary tract inflammation - infection, neoplasia, crystals
Genital tract inflammation - infection, neoplasia, bleeding
