Physical examination of Urine

Question 1

what is a normal amount of urine excreted in a day for an adult?

Answer 1

600 to 1800 ml/day, less than 400 overnight

Question 2

what is excretion of >500 mL at night termed and suspicious for?

Answer 2

nocturia; chronic progressive renal failure

Question 3

define polyuria in terms of volume

Answer 3

> 3 liters per day

Question 4

what is the term for ANY increase in urine excretion and name some causes

Answer 4

diuresis; excess fluid intake, diuretic therapy, hormonal imbalance, kidney dysfunction, drugs ie alcohol or caffeine

Question 5

what can cause oliguria, less than 400 mL/day?

Answer 5

decreased renal blood flow due to dehydration, shock (hypotension), renal disease including obstruction, tubular dysfunction, nephrotic syndrome, end stage kidney disease

Question 6

what can cause anuria?

Answer 6

acute kidney failure due to shock, heart failure, drugs, toxins
Or obstruction, HTRs

Question 7

two ways to measure urine concentration (different principle)

Answer 7

by specific gravity, or osmolality

Question 8

Two ways to measure specific gravity of urine

Answer 8

reagent strip, or refractometry

Question 9

the formula for osmolality using the freezing point method

Answer 9

1000 mOsm particles/ 1.86 C = mOsm (what you’re looking for)/ measured FP of sample

Question 10

what are two methods of determining osmolality?

Answer 10

FP and VP

Question 11

what can cause a discrepancy btw specific gravity by refractometer (too high, >1.040) and reagent strip (normal)?

Answer 11

high molecular weight substance such as x-ray contrast, mannitol, or large quantities of protein or glucose

Question 12

what can cause acidic urine (pH 4.5 to 6.9)

Answer 12

high protein diet or cranberries, sleep, metabolic or resp acidosis, acid-producing bacteria such as E. coli, meds incl vit C, methionine….

Question 13

causes of alkaline urine

Answer 13

vegetarian diet, alkalosis, urease producing bacteria like Proteus or Pseudomonas; meds like Na bicarb, acetazolamide, K citrate

Question 14

what is the principle of the urine pH by reagent strip method?

Answer 14

double-indicator system, meaning two dyes methyl red and bromthymol blue give distinct color changes from orange to green to blue

Question 15

what is the “alkaline tide”

Answer 15

during and after a meal the urine is more alkaline

Question 16

3 reasons a urine may have a physiologically impossible pH >8?

Answer 16

improper storage allowed urease producers to increase ( proteus, pseudomonas); adulterated specimen; pt was given very alkaline substance that was excreted by the kidneys

Question 17

what was odor historically important for in urinalysis, and what about now?

Answer 17

for discovery of phenylketonuria; not used as routine urinalysis component now unless particularly strong

Question 18

give possible cause of the odors:

1. ammonia
2. cabbage
3. mousy/ barny

Answer 18

1. left standing/ old urine
2. methionine malabsorption
3. phenylketonuria

Question 19

more odors, give causes

1. sweet/fruity
2. rancid
3. rotting fish

Answer 19

1. ketones
2. tyrosinemia
3. trimethylaminuria

Question 20

what are some only-pathologic causes of turbidity/ lack or urin clarity?

Answer 20

RBCs, WBCs, bacteria, yeast, trichomonads, renal epithelials, FAT, ABNORMAL crystals, calculi

Question 21

deifferentiate cause of yellow vs white urine foam

Answer 21

yellow: bilirubin
white: excess protein, albumin mostly

Question 22

List 5 recommendations for evaluation of urine’s physical characteristics

Answer 22

1. use well-mixed spec
2. view through clear container
3. against a white background
4. eval a consistent depth/volume
5. use adequate lighting