physical properties Flashcards
list what the physical examination of urine includes
color, clarity, specific gravity
list possible causes of urine color change
- normal metabolic functions
- physical activity
- ingested materials
- pathological conditions
- presence of bacteria
name the pigment that causes urine to be yellow
urochrome
describe urochrome
- lipid soluble pigment
- product of endogenous metabolism
- produced/excreted at constant rate
- production dependent on body’s metabolic state
- darkens on light exposure
how does concentration effect urine color
more concentrated will be darker
true or false:
uroerythrin is a normal pink pigment of urine
true
describe uroerythrin
- pink pigment
- pigment attaches to urates to produce amorphous material
describe urobilin
- low levels cause a brown orange color
- oxidation product of urobilinogen
- urobilinogen is normal part of urine (colorless)
describe a normal possible cause of orange-brown urine
presence of urobilin
- oxidation product of urobilinogen
describe an abnormal cause of dark yellow/amber/orange pigmented urine
- bilirubin (yellow foam)
- urobilin (photo OX [no yellow foam])
- pyridium
describe a quick way to determine presence of bilirubin in urine
yellow foam when shaken
what does a white foam when urine is shaken indicate
presence of proteins
describe pyridium
- drug that can cause orange urine
- used to treat UTI
- yellow foam when shaken
- interferes with dipstick due to pigment
describe a test that differentiates bilirubin from pyridium in an orange urine
ictotest
describe causes of yellow-green urine (abnormal)
- photo ox of bilirubin to biliverdin
describe possible causes of red/pink/brown urine color
- blood (red)
- ox of hemoglobin in acid urine (brown)
describe causes of red/pink/brown urine
- hemoglobin and myoglobin cause red urine
true or false:
red blood cells produce a red and cloudy urine
true
describe how to differentiate presence of RBCs or hemoglobin in urine
- 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
true or false:
hemoglobin and myoglobin both cause red and clear urine
true
how is hemoglobin and myoglobin differentiated
by comparing urine to plasma
- myoglobin plasma is clear
- hemoglobin plasma is red
what causes ‘port wine red’
oxidation of porphobilinogen to porphyrins
describe nonpathological causes of red/pink/brown urine
- menstruation
- pigmented foods
- medication
describe what causes brown/black urine upon being left out
- melanin
- homogentisic acid
describe melanin in urine
- causes brown/black coloration
- produced in excess in malignant melanoma (brown/black color)
- oxidation to melanogen
describe homogentisic acid
- metabolite of phenylalanine
- produced from an inborn error of metabolism
- when present called alkaptonuria
- dark brown/black urine
list medications that can cause brown/black urine
- levodopa
- phenol derivatives
- metranidazole (antibacterial)
describe bacteria that can cause green~blue urine
pseudomonas UTI
describe bacteria that can cause blue urine
indican in intestinal tract infections
- tryptophan -> indole -> indican
describe causes of purple urine
- klebsiella, providencia spp
- purple in catheter
describe non bacterial causes of blue/green urine
- medication
- breath mint
- phenol derivative medications
specific gravity of colorless urine
low SG
specific gravity of dark yellow urine
high SG
bluish urine cause
indican -> bacterial infeciton
orange/yellow - green/amber urine cause with yellow foam
bilirubin
orange urine with yellow foam
pyridium
greenish urine cause
bilirubin ox to biliverdin
red urine possible causes
- RBC (whole or lysed)
- hemoglobin or myoglobin (plasma differentiate)
- porphyrin
- rifampin antibiotic
brown urine causes
- hemoglobin oxidized to methemoglobin
describe a normal cause of turbid urine
precipitation of amorphous material
list causes of non pathological turbid urine
- specimen allowed to stand
- refrigerated sample
- squamous epithelial cells
- mucus
- crystals
- semen
- fecal
- radiographic media
- tulcum powder
- medications
describe most common causes of pathologic turbidity
- RBC, WBC, bacteria
describe less common causes for pathological turbidity
- yeast
- cells
- abnormal crystals
- lymph fluid
- lipids
if a urine is acidic, what will cause turbidity
amorphous urates, radiographic contrast media
if urine is alkaline what may cause turbidity
amorphous phosphates, carbonates
if the turbid material is soluble with heat, what may it be
amorphous urates or uric acid crystals
if turbid urine is soluble in dilute acetic acid, what may cause it
RBCs, amorphous phosphates, carbonates (similar to alkaline)
if material is insoluble in dilute acetic acid what may it be
- WBC
- bacteria
- yeast
- sperm
if material is soluble in ether what may it be
lipids, lymphatic fluid, chyle
define specific gravity
a measure of the density of the dissolved chemicals in a urine specimen
what is specific gravity influenced by (important)
by the number of particles present and the size of the particles
describe principle of refractometers
dissolved particles in a soln will change the velocity and angle of light that pass through the solution
how does concentration impact refractometer reading
increases - increases angle that the light hits the scale
list materials used for refractometer calibration
- DI water - 1.000
- 5% NaCl - 1.022
- 9% sucrose - 1.034
how does a pH of >6.5 impact strip reading
decrease reading results due to bromothymol blue indicator
true or false:
reagent strips measure only ionic solutes
true
define isosthenuric urine
specific gravity of 1.01
define hyposthenuric urine
specific gravity <1.01
define hypersthenuric urine
specific gravity >1.01
random specimen specific gravity ranges
1.002-1.035
describe what may cause abnormally high specific gravity results
intravenous injection
how is urine diluted to retest for high specific gravity
1:2 with distilled water
