Physical examination of Urine Flashcards
what is a normal amount of urine excreted in a day for an adult?
600 to 1800 ml/day, less than 400 overnight
what is excretion of >500 mL at night termed and suspicious for?
nocturia; chronic progressive renal failure
define polyuria in terms of volume
> 3 liters per day
what is the term for ANY increase in urine excretion and name some causes
diuresis; excess fluid intake, diuretic therapy, hormonal imbalance, kidney dysfunction, drugs ie alcohol or caffeine
what can cause oliguria, less than 400 mL/day?
decreased renal blood flow due to dehydration, shock (hypotension), renal disease including obstruction, tubular dysfunction, nephrotic syndrome, end stage kidney disease
what can cause anuria?
acute kidney failure due to shock, heart failure, drugs, toxins
Or obstruction, HTRs
two ways to measure urine concentration (different principle)
by specific gravity, or osmolality
Two ways to measure specific gravity of urine
reagent strip, or refractometry
the formula for osmolality using the freezing point method
1000 mOsm particles/ 1.86 C = mOsm (what you’re looking for)/ measured FP of sample
what are two methods of determining osmolality?
FP and VP
what can cause a discrepancy btw specific gravity by refractometer (too high, >1.040) and reagent strip (normal)?
high molecular weight substance such as x-ray contrast, mannitol, or large quantities of protein or glucose
what can cause acidic urine (pH 4.5 to 6.9)
high protein diet or cranberries, sleep, metabolic or resp acidosis, acid-producing bacteria such as E. coli, meds incl vit C, methionine….
causes of alkaline urine
vegetarian diet, alkalosis, urease producing bacteria like Proteus or Pseudomonas; meds like Na bicarb, acetazolamide, K citrate
what is the principle of the urine pH by reagent strip method?
double-indicator system, meaning two dyes methyl red and bromthymol blue give distinct color changes from orange to green to blue
what is the “alkaline tide”
during and after a meal the urine is more alkaline
3 reasons a urine may have a physiologically impossible pH >8?
improper storage allowed urease producers to increase ( proteus, pseudomonas); adulterated specimen; pt was given very alkaline substance that was excreted by the kidneys
what was odor historically important for in urinalysis, and what about now?
for discovery of phenylketonuria; not used as routine urinalysis component now unless particularly strong
give possible cause of the odors:
- ammonia
- cabbage
- mousy/ barny
- left standing/ old urine
- methionine malabsorption
- phenylketonuria
more odors, give causes
- sweet/fruity
- rancid
- rotting fish
- ketones
- tyrosinemia
- trimethylaminuria
what are some only-pathologic causes of turbidity/ lack or urin clarity?
RBCs, WBCs, bacteria, yeast, trichomonads, renal epithelials, FAT, ABNORMAL crystals, calculi
deifferentiate cause of yellow vs white urine foam
yellow: bilirubin
white: excess protein, albumin mostly
List 5 recommendations for evaluation of urine’s physical characteristics
- use well-mixed spec
- view through clear container
- against a white background
- eval a consistent depth/volume
- use adequate lighting
