Exam 2 Flashcards
What are the physical properties of urine?
Color, Clarity, Foam (not reported), Odor, Concentration, Volume
What is urochrome and what is its color?
It is a normal product of metabolism and it is yellow.
What is urobilin and what color is it?
Normal urine constituent; orange-brown pigment
What is uroerythrin? What color is it?
Normal urine constituent that has a brick dust appearance; pink pigment
What may cause a urine sample to be orange?
phenazopyridine, warfarin/rifampin, or consumption of carotene
What may cause a urine sample to be bright yellow?
riboflavin or b-vitamins
What may cause a urine sample to be yellow-brown?
nitrofurantoin (antibiotic)
What may cause a urine sample to be pink?
Blood in urine, presence of porphobilin
What may cause urine samples to be red?
RBCs or HGB, beet ingestion, senna (laxative)
What may cause a urine sample to be red-purple?
oxidation of phorphobilinogen to colored compounds or improper storage
What may cause a urine sample to be brown?
myoglobin in the urine, methemoglobin, or metronidazole
What may cause a urine sample to be dark brown to black?
malignant melanoma, homogentistic acid (alkaline urine)
What may cause a urine sample to be blue or green?
Pseudomonas infection, methylene blue, chlorophyll, amitriptyline, or indomethacin
What may cause a urine sample to be dark yellow-green?
biliverdin
What may cause a urine sample to be dark yellow or amber?
concentrated, excessive urobilin, or bilirubin
Is foam reported on a urinalysis?
No
What does large amounts of foam indicate after a urine sample is shaken up?
Presence of protein or bilirubin
What does thick, large volume of white foam in urine indicate?
Large amounts of protein (albumin) in the urine
What does yellow foam in urine indicate?
Bilirubin in the urine
Describe “clear” urine
No particles present, transparent
Describe “hazy/slightly cloudy” urine
Visible particles are present, newsprint can be read when viewed through urine tube
Describe “cloudy” urine
Significant particulate matter, newsprint is blurred/difficult to read
Describe “turbid” urine
Opaque - newsprint cannot be seen when viewed through urine tube
Is urine odor reported?
No
What is the cause of mousy/barny urine odor?
Phenylketonuria
What is the cause of sweet/fruity urine odor?
Ketone production due to diabetes mellitus
What is the cause of bleach-smelling urine?
Adulteration of specimen (I.e. drug testing)
What is the cause of ammoniacal smelling urine?
“old” urine/improperly stored
What is the smell of normal urine?
Faintly aromatic
What foods can change the smell of urine?
Asparagus, garlic, onions
What is the cause of menthol-smelling urine?
Phenol-containing medications
What two tests are used to indicate urine concentration?
Specific Gravity or Osmolality
Specific gravity
the mass of solutes present in urine
Osmolality
the number of solutes present in a solution
Is specific gravity or osmolality more specific when it comes to measuring urine concentration?
osmolality
What is the physiological possible range of specific gravity of urine?
1.002 - 1.040
Specific gravity is a measure of urine _______.
density
Refractometry
used to measure SG based on refractive index of light
T/F: Refractometry measures ALL solutes in a solution, as opposed to only ionic solutions on a dipstick SG test.
True
What factors affect the refractive index of a solution?
Wavelength of light used
Temperature of the solution
Concentration of the solution
Each g/dL of protein present increases SG by ____.
0.003
Each g/dL of glucose present increases SG by ____.
0.002
What may cause physiological impossible SG results?
Presence of radiographic contrast media
What limitation does the reagent strip method for SG have?
It only measures ionic specific gravity (charged solutes). It disregards protein, glucose, urea, and radiographic media.
Acidic urine causes SG to falsely ______.
increase
Alkaline urine causes SG to falsely ______.
decrease
What is normal urine osmolality?
275-900 mOsm/kg
Does molecular weight have an affect on specific gravity or osmolality?
It has an affect on SG. It does not have an affect on osmolality because osmolality measures # of solutes, not mass.
Would NaCl (MW 58) or Glucose (MW 180) have a higher osmolality?
NaCl would have a higher osmolality because it dissociates in solution into 2 osmoles. Glucose does not dissociate in solution.
What are the 4 colligative properties?
Freezing point depression
Vapor pressure depression
Osmotic pressure elevation
Boiling point elevation
If you were given a sample’s freezing point, how would you determine osmolality? (calculation)
1000 X CROSS MULTIPLY :)
____ = ____
-1.86 C freezing point
nocturia
when an individual excretes >500mL urine at night
anuria
complete lack of urine excretion
oliguria
decrease in urine excretion (<400 mL/day)
polyuria
excretion of >3L of water daily (excess)
diuresis
increase in urine excretion (>1800mL/day)
List the 11 possible tests included on a reagent strip for chemical testing.
pH, protein, glucose, blood, leukocyte esterase, specific gravity, bilirubin, urobilinogen, nitrite, ascorbic acid, ketones
Reagent strips must be protected from:
moisture, chemicals, heat, and light
hyposthenuric
urine with a SG <1.010
hypersthenuric
urine with a SG >1.010
Normal urine SG range
1.010-1.025
isosthenuria
SG of 1.010
principle of specific gravity reagent strip test
reagent strip test that only measures ionic (charged) solutes
urine pH range
4.5-8.0
principle of pH reagent strip test
a double-indicator system using bromothymol blue and methyl red
alkaline tide
urine is more alkaline following a meal
common reasons for pH over 8.0 (impossible)
improper storage, highly alkaline substance ingested, or adulterated specimen
What tests should be negative in urine?
protein, glucose, nitrite, leukocyte esterase, ketones, bilirubin, and blood
proteinuria (what is it and what is it caused by)
increased amount of protein in the urine, caused by increased levels of albumin (first indicator of renal disease)
Cause of Prerenal proteinuria
caused by increased quantities of plasma proteins
glomerular proteinuria
tubular capacity for reabsorption (Tm) is exceeded
tubular proteinuria
tubular reabsorptive function is altered or impaired; plasma proteins that are normally reabsorbed will be increased in urine
what is the most common type of proteinuria AND the most serious clinically?
glomerular proteinuria
cause of renal proteinuria
gomerular or tubular proteinuria
postrenal proteinuria
inflammation in the urinary tract (normal kidney function, something after kidneys is introducing proteins)
conditions resulting in prerenal proteinuria
septicemia, hemoglobinuria, myoglobinuria, or multiple myeloma and macroglobulinemia
postural (orthostatic) proteinuria
type of functional proteinuria characterized by urinary excretion of proteins only when the individual is in an upright position
SSA precipitation test - to which reagent strip test does it relate to? what does a positive result look like?
Protein (ALL protein) - positive result is white/turbid, the more turbid the higher + value
What is the principle of protein reagent strip test?
the protein error of indicators
limitation of protein reagent strip test
only detects albumin; does not detect other proteins
What reagent strip test does Sensitive Albumin Tests relate to?
Protein - tests for small amounts of albumin <2.0 mg/dL that strip test may not detect.
hematuria
abnormal amount of RBCs in urine (cloudy sample)
hemoglobinuria
presence of hemoglobin in the urine (clear sample)
myoglobinuria
muscle damage that causes release of myoglobin in the blood
hemosiderin
a storage form of iron
principle of the blood reagent strip test
pseudoperoxidase activity of the heme moiety
T/F: <2.0 mg/dL of albumin the urine is considered abnormal.
False. It is normal to have very small amounts of albumin in the urine.
What is the normal level of WBC in the urine?
10 WBC/uL
What does increased number of WBC/leukocyte esterase in the urine indicate?
inflammation
When are WBC susceptible to lysis in the urine?
hypotonic and alkaline urine
Limitations of leukocyte esterase reagent strip test
Does not detect lymphocytes
Principle of nitrite reagent strip test
formation of diazonium salt and an azo coupling reaction
What does nitrite in the urine indicate? Why?
Bacterial infection (UTI). Bacteria (such as E. coli) can reduce nitrate to nitrite.
Glucosuria
presence of glucose in the urine
Glycosuria
presence of non-glucose sugars in the urine
What is the renal threshold level of glucose? What happens if this is exceeded?
160-180 mg/dL. If it is exceeded, glucose will be excreted in the urine.
The most common disease that causes hyperglycemia and glucosuria
Diabetes mellitus
principle of glucose reagent strip test
double sequential enzyme reaction that detects only glucose
what is considered normal excretion of glucose in the urine?
<20 mg/dL
Clinitest - what is it? what reagent strip test does this relate to? What does a positive result look like?
Copper reduction test to look for any reducing sugar in the urine. Relates to glucose test but is less limiting. A positive result will be orange.
Normal amount of ketones in urine?
No ketones in urine should be present
What are the 3 types of ketones? Which is the most common found in serum/urine?
Acetoacetate
Beta-hydroxybutyrate (MOST COMMON)
Acetone
What is the first ketone formed by the liver cells?
Acetoacetate. It can form into acetone or beta-hydroxybutyrate (most common).
Which ketones are detected in testing?
Only acetoacetate or acetone. There are no methods of detection for beta-hydroxybutyrate.
Principle of the ketone reagent strip test
Nitroprusside reaction
What reagent strip test does Acetest relate to? What does a positive reaction look like?
Acetest detects ketones in the urine. A positive result is a purple color.
T/F: ANY amount of bilirubin in the urine is clinically significant
True
What is ascorbic acid? What reagent strip tests are vulnerable to ascorbic acid interference? Does it cause a false negative or a false positive for these tests?
Vitamin C.
It may interfere with blood, bilirubin, glucose, and nitrite strip tests by causing a false NEGATIVE.
principle of bilirubin reagent strip test
coupling reaction of a diazonium salt to form an azo dye
Bilirubin vs urobilinogen
Bilirubin comes from breakdown of hemoglobin; Urobilinogen comes from breakdown of bilirubin
What reagent strip test does the icotest relate to? What does a positive result look like?
Bilirubin - must more sensitive than than reagent strip test. positive result will be a purple/bruise color
principle for urobilinogen strip test
Ehrlich’s reaction or azo coupling reaction
Normal urobilinogen in urine
<1 mg/dL
What is the only component that is normal to find small amounts of in urine?
Urobilinogen
Sternheimer-Malbin stain
supravital stain (stains live parts of cells) consisiting of crystal violet and safranin
2% acetic acid for use in microscopy
can help ID WBC cause it lyses RBC
0.5% Toluidine blue stain
helps to distinguish cells of similar size
Sudan III stain or oil red O stain
Stains fats or lipids orange/red
Prussian Blue stain
helps to visualize hemosiderin (iron aggregates)
Hansel stain
used to ID eosinophils in urine
Most common type of microscopy
brightfield
What produces a maltese cross pattern with polarized light under a microscope?
Cholesterol
Normal reference range for RBC in urine microscopy
0-3 per HPF
Normal reference range for WBC in urine microscopy
0-8 per HPF
Normal reference range for casts in urine microscopy
0-2 hyaline casts per LPF
Normal reference range for squamous/transitional/renal cells in urine microscopy
squamous: few per LPF
transitional/renal: few per HPF
Normal reference range for bacteria and yeast in urine microscopy
none
Normal reference range for abnormal crystals in urine microscopy
none
What does eosinophiluria indicate?
acute interstitial nephritis (AIN)
Oval fat bodies
monocyte/macrophage that ingested lipoproteins and fat
Presence of many renal tubular epithelial cells indicates what?
intrinsic renal disease
What are casts made of?
uromodulin AKA Tam-Horsfall protein
What promotes disintegration of casts?
Hypotonic and alkaline urine
What enhances cast formation?
acidic urine, increased solute concentration (hypertonic), urine stasis, and increased plasma proteins
most clinically significant crystals are found in ______ urine.
acidic
Crystals ending in what are typically found in acidic urine?
“Urate”
Where are amorphous urates commonly found? Are they normal?
In “brick dust” samples caused by uroerythrin deposits. Yes they are normal.
What crystal is a small ball or sphere and yellow-brown?
acid urates
What crystal is rhombic or diamond shape and ONLY found in acidic urine <5.7?
Uric acid
What crystal is envelope shaped in dihydrate form and dumbbell shaped in monohydrate form, and can be found in any pH of urine?
Calcium oxalate
Clinical significance of high levels of calcium oxalate in urine
ingestion of ethylene glycol (antifreeze)
What is the most frequently observed crystal in urine?
Calcium oxalate
What do crystals found in alkaline urine end with?
“Phosphate” + ammonium biurate
What crystal looks like grains of sand and is found in white or gray macroscopic precipitate?
Amorphous phosphate
What crystal looks like a coffin lid and can be associated with kidney stones?
Triple phosphate
What crystal is found in alkaline urine, indicates dehydration, and has a thorny apple appearance?
Ammonium biurate
What crystal can produce CO2 gas with acetic acid?
Calcium carbonate
What crystal of metabolic origin appears as fine needles and is yellow-brown in color?
Bilirubin
What metabolic crystal is hexagonal and can indicate hereditary cystinosis?
Cystine
What crystals are fine, hairlike delicate needles? Which are concentric circles/radial striations? What is the clinical significance of finding these?
Tyrosine and Leucine
Found in patients that cannot metabolize certain amino acids
What crystal appears as having notched corners, that must be accompanied by evidence of lipiduria and proteinuria?
Cholesterol
What drug crystal can be found in the urine that looks like sheaves of wheat?
Sulfonamides
What can cause flat, elongated parallelogram shaped plates in urine?
Radiographic contrast media
What must be moving in order to report it out?
Trichomonads
What stain is used to identify hemosiderin?
Prussian blue stain