quantity/composition of plasma presented to kidney
renal function (filtration, tubular secretion/absorption)
materials added to glomerular fluid from kidneys, ureters, bladder, urethra, and prepuce/vagina/vulva
4 methods of collection
manual expression (not recommended, damage or increase RBC)
Minimum urine for UA
Voided sample of urine
free catch, midstream preferred.
Preferred method for large animals.
bacteria (genital vs UTI), epithelial cells, spermatozoa, and leukocytes in sample.
preferred method in small animals and for urine culture.
Danger of iatrogenic hemorrhage and accidental enterocentesis (bowel loop over bladder). Can also cause increase in RBCs
Catheterized collection of urine
commonly contaminated by epithelial cells, blood from iatrogenic hemorrhage, lubricant and bacteria
why fresh urine preferred
Should be within 30 minutes.
Urea hydrolysis becomes ammonium, increasing pH of urine, which can break down casts or cells. Oxidation can make in vitro crystals, overgrowth of bacteria can also effect ketones and glucose. Urine can change color.
3 hours max, refrigerate after 30 minutes.
Can add chemical preservatives
warm to room temp before evaluation (redissolve precipitates and enzymes will function properly)
4 parts of urinalysis
visual inspection (color, transparency, odor)
chemical analysis (protein, glucose, ketones, etc)