physical properties

Question 1

list what the physical examination of urine includes

Answer 1

color, clarity, specific gravity

Question 2

list possible causes of urine color change

Answer 2

• normal metabolic functions
• physical activity
• ingested materials
• pathological conditions
• presence of bacteria

Question 3

name the pigment that causes urine to be yellow

Answer 3

urochrome

Question 4

describe urochrome

Answer 4

• lipid soluble pigment
• product of endogenous metabolism
• produced/excreted at constant rate
• production dependent on body’s metabolic state
• darkens on light exposure

Question 5

how does concentration effect urine color

Answer 5

more concentrated will be darker

Question 6

true or false:
uroerythrin is a normal pink pigment of urine

Answer 6

true

Question 7

describe uroerythrin

Answer 7

• pink pigment
• pigment attaches to urates to produce amorphous material

Question 8

describe urobilin

Answer 8

• low levels cause a brown orange color
• oxidation product of urobilinogen
• urobilinogen is normal part of urine (colorless)

Question 9

describe a normal possible cause of orange-brown urine

Answer 9

presence of urobilin
- oxidation product of urobilinogen

Question 10

describe an abnormal cause of dark yellow/amber/orange pigmented urine

Answer 10

• bilirubin (yellow foam)
• urobilin (photo OX [no yellow foam])
• pyridium

Question 11

describe a quick way to determine presence of bilirubin in urine

Answer 11

yellow foam when shaken

Question 12

what does a white foam when urine is shaken indicate

Answer 12

presence of proteins

Question 13

describe pyridium

Answer 13

• drug that can cause orange urine
• used to treat UTI
• yellow foam when shaken
• interferes with dipstick due to pigment

Question 14

describe a test that differentiates bilirubin from pyridium in an orange urine

Answer 14

ictotest

Question 15

describe causes of yellow-green urine (abnormal)

Answer 15

• photo ox of bilirubin to biliverdin

Question 16

describe possible causes of red/pink/brown urine color

Answer 16

• blood (red)
• ox of hemoglobin in acid urine (brown)

Question 17

describe causes of red/pink/brown urine

Answer 17

• hemoglobin and myoglobin cause red urine

Question 18

true or false:
red blood cells produce a red and cloudy urine

Answer 18

true

Question 19

describe how to differentiate presence of RBCs or hemoglobin in urine

Answer 19

• both will be red and cloudy before being spun
• after being spun RBCs will form a pellet
• after being spun hgb will remain in supernatant

Question 20

true or false:
hemoglobin and myoglobin both cause red and clear urine

Answer 20

true

Question 21

how is hemoglobin and myoglobin differentiated

Answer 21

by comparing urine to plasma
- myoglobin plasma is clear
- hemoglobin plasma is red

Question 22

what causes ‘port wine red’

Answer 22

oxidation of porphobilinogen to porphyrins

Question 23

describe nonpathological causes of red/pink/brown urine

Answer 23

• menstruation
• pigmented foods
• medication

Question 24

describe what causes brown/black urine upon being left out

Answer 24

• melanin
• homogentisic acid

Question 25

describe melanin in urine

Answer 25

- causes brown/black coloration - produced in excess in malignant melanoma (brown/black color) - oxidation to melanogen

Question 26

describe homogentisic acid

Answer 26

- metabolite of phenylalanine - produced from an inborn error of metabolism - when present called alkaptonuria - dark brown/black urine

Question 27

list medications that can cause brown/black urine

Answer 27

- levodopa - phenol derivatives - metranidazole (antibacterial)

Question 28

describe bacteria that can cause green~blue urine

Answer 28

pseudomonas UTI

Question 29

describe bacteria that can cause blue urine

Answer 29

indican in intestinal tract infections - tryptophan -> indole -> indican

Question 30

describe causes of purple urine

Answer 30

- klebsiella, providencia spp - purple in catheter

Question 31

describe non bacterial causes of blue/green urine

Answer 31

- medication - breath mint - phenol derivative medications

Question 32

specific gravity of colorless urine

Answer 32

low SG

Question 33

specific gravity of dark yellow urine

Answer 33

high SG

Question 33

bluish urine cause

Answer 33

indican -> bacterial infeciton

Question 34

orange/yellow - green/amber urine cause with yellow foam

Answer 34

bilirubin

Question 34

orange urine with yellow foam

Answer 34

pyridium

Question 35

greenish urine cause

Answer 35

bilirubin ox to biliverdin

Question 36

red urine possible causes

Answer 36

- RBC (whole or lysed) - hemoglobin or myoglobin (plasma differentiate) - porphyrin - rifampin antibiotic

Question 37

brown urine causes

Answer 37

- hemoglobin oxidized to methemoglobin

Question 38

describe a normal cause of turbid urine

Answer 38

precipitation of amorphous material

Question 39

list causes of non pathological turbid urine

Answer 39

- specimen allowed to stand - refrigerated sample - squamous epithelial cells - mucus - crystals - semen - fecal - radiographic media - tulcum powder - medications

Question 40

describe most common causes of pathologic turbidity

Answer 40

- RBC, WBC, bacteria

Question 41

describe less common causes for pathological turbidity

Answer 41

- yeast - cells - abnormal crystals - lymph fluid - lipids

Question 42

if a urine is acidic, what will cause turbidity

Answer 42

amorphous urates, radiographic contrast media

Question 43

if urine is alkaline what may cause turbidity

Answer 43

amorphous phosphates, carbonates

Question 44

if the turbid material is soluble with heat, what may it be

Answer 44

amorphous urates or uric acid crystals

Question 45

if turbid urine is soluble in dilute acetic acid, what may cause it

Answer 45

RBCs, amorphous phosphates, carbonates (similar to alkaline)

Question 46

if material is insoluble in dilute acetic acid what may it be

Answer 46

- WBC - bacteria - yeast - sperm

Question 47

if material is soluble in ether what may it be

Answer 47

lipids, lymphatic fluid, chyle

Question 48

define specific gravity

Answer 48

a measure of the density of the dissolved chemicals in a urine specimen

Question 49

what is specific gravity influenced by (important)

Answer 49

by the number of particles present and the size of the particles

Question 50

describe principle of refractometers

Answer 50

dissolved particles in a soln will change the velocity and angle of light that pass through the solution

Question 51

how does concentration impact refractometer reading

Answer 51

increases - increases angle that the light hits the scale

Question 52

list materials used for refractometer calibration

Answer 52

- DI water - 1.000 - 5% NaCl - 1.022 - 9% sucrose - 1.034

Question 53

how does a pH of >6.5 impact strip reading

Answer 53

decrease reading results due to bromothymol blue indicator

Question 54

true or false: reagent strips measure only ionic solutes

Answer 54

true

Question 55

define isosthenuric urine

Answer 55

specific gravity of 1.01

Question 56

define hyposthenuric urine

Answer 56

specific gravity <1.01

Question 57

define hypersthenuric urine

Answer 57

specific gravity >1.01

Question 58

random specimen specific gravity ranges

Answer 58

1.002-1.035

Question 59

describe what may cause abnormally high specific gravity results

Answer 59

intravenous injection

Question 60

how is urine diluted to retest for high specific gravity

Answer 60

1:2 with distilled water