Exam 3: Lab Evaluation of the Kidney and Urinalysis Flashcards
We know the basic functions of the kidney and that it makes erythropeitin… What else?
Vitamin D
What are the isosthenuria values?
1.008-1.012
What are the values for specific gravity in dehydrated animals?
Dog> 1.030
Cat > 1.035
Horse and cattle > 1.025
What are some prerenal reasons for increased BUN?
decreased GFR dehydration, shock (most common cause)
increased protein catabolism (creatinine unaffected) (more ammonia presented to liver, more urea formed, generally mild increases will be: fever, starvation, massive necrosis, prolonged exercise. hemorrhage within small intestine.
An dog has high BUN and creatinine with a specfic gravity of 1.045. Is this pre or post renal azotemia? How do you know?
You know it’s prerenal because he is concentrating his urine
Does dilute urine always mean renal failure? Explain.
No, you can get dilute urine in cases where tubules do not respond to ADH, diabetes insipidous, Addison’s disease, liver failure, polydipsia…
Like azotemia you can have pre, (actual), and post glomerular proteinuria, what is damaged in each and how much protein is lost?
preglomerular proteinemia have sneaky proteins that can get out like myoglobin, hemoglobin, and bence jones but these would not be detected on a dipstick and fever and exercise can ionduce this mild increase.
in glomerular proteinemia there is damage to the glomerulus and filtering selectivity which allows moderte to a large amt of proteins to get out.
postglomerula proteinemia can be dure to renal tubular dysfunction (mild), hemorrhage which you would see a lot of blood in and inflammation which would occur with few WBCs. (inflammation and hemorrhage could be: kidneys, ureter, bladder, urethra or genital tract)
How can you distinguish betwen glomerular damage and inflammation?
glomerula damage would have a “quiet” or clean sediment. with inflammation, will see more WBCs.
what is GGT/NAG a good indicator of and where can it be found?
found within renal tubular epithelial cells and is reeased as cells die. GGT is shown to be a good predictor of aminoglycoside induced mephrotoxicity
Cow, free catch urine, skin not cleaned. Evaluates the…
Upper urinary tract
Lower urinary tract
Upper and lower urinary tract
Urogenital tract
Urogenital tract & perianal area
Urogenital tract & perianal area
Free catch urine collected from an IM dog evaluates the…
Bladder only
Upper and lower urinary tract
Urogenital tract only
Urogenital tract and perianal contents
Urogenital tract only
A female cat has pyuria in a sample collected by cystocentesis. What is/are the most likely source(s) of inflammation?
Kidney (e.g. pyelonephritis) only
Urinary Bladder (cystitis) only
Reproductive (vaginitis, metritis) only
A and/or B
A, B, and/or C
a and or b
Kidney (e.g. pyelonephritis) only
Urinary Bladder (cystitis) only
What are considerations for Timing of Collection?*
First morning specimen in diurnal animals is preferred for evaluating tubular function (most concentrated) and the higher acidity preserves proteinaceous structures. However, cells and fastidious bacteria dislike urine environment so freshly formed urine (random) is better for cytologic evaluation and culture of these organisms. Urine for culture is best collected by cystocentesis.
3-4 hr postprandial is best for detecting glucosuria and other effects of diet (crystals, pH).
Collect sample prior to giving diagnostic (Dx) (e.g. radiographic contrast dyes) or therapeutic (Tx)(antibiotics, fluids, hetastarch) agents that may interfere with testing.
What containers; how label and store?
Goal: maintain sample integrity and safety of handler. All samples must be labeled.
Clean disposable collection cups with tight fitting lids ideal, can also use sterilizable reusable cups. Syringe (from cystocentesis), tightly capped.
Clear containers facilitate gross observations, but avoid prolonged exposure to light because bilirubin is degraded by light.
Avoid washed food containers due to detergents that may interfere with dipstick results and other contaminants.
Avoid flimsy/leaky containers: zoonotic organisms (e.g. leptospira, an emerging infectious disease in humans and dogs) may transfer infectious organisms to the owner or sample handler, diagnostic/therapeutic agents (e.g. radioisotopes, chemotherapeutics) might be toxic, dehydration/concentration, or volatilization w/ subsequent loss of ketones.
Examine while FRESH; w/in 30 minutes of collection is ideal. Up to 2 hours is likely common. Refrigerate if this is not possible and bring to room temperature prior to testing because dipstick reactions perform poorly when urine is cold. DO NOT FREEZE! Cells lyse upon thawing.
Refrigeration slows bacterial and pH changes but may precipitate massive crystal formation which obscures other findings. Some biochemical dipstick reactions are slowed by cold temperatures. Therefore, refrigerated urine should be warmed to room temperature prior to testing.
What are effects on urine that is allowed to sit at room temperature too long?
Sitting at room temperature for prolonged periods:
pH increases (more alkaline) due to proliferation of urease-producing bacterial contaminants
Crystals change, form or dissolve due to changing pH
Bacteria multiply (a single bacterium can produce ~5 billion offspring in about 12 hours).
Cell morphology is altered, especially for cytologic examination
