Microscopic exam of urine pt 3 Flashcards
Two types of amorphous crystals
- Amorphous urates: acidic urine
- Amorphous phosphates: alkaline urine
Color of amorphous urates and phosphates
Urates = pink
Phosphates = white
Amorphous urates and phosphates solubility
Urates = heat and alkaline pH
Phosphates = acetic acid
ID the element
Amorphous crystals
Sodium urate
- Normal, appears by refrigeration
- Caused by protein rich diet, typically NOT reported if seen
List normal crystals found in acidic urine
- Uric acid
- Calcium oxalate
- Hippuric acid
List normal crystals found in alkaline urine
- Ammonium biurate
- Calcium carbonate
- Calcium phosphate
- Triple phosphate
- Calcium oxalate possible
- Hippuric acid possible
List abnormal crystals
- Cystine
- Cholesterol
- Tyrosine
- Leucine
- Bilirubin
- Radiographic dye
- Sulfonamide
- Acyclovir
- Ampicillin
Abnormal crystals are typically found in what pH?
Acidic urine
ID the element
Sodium urates
ID the element
Uric acid
lemon
ID the element
Uric acid
rhombus
ID the element
Uric acid
barrels
ID the element
Uric acid
rosettes
Are uric acid crystals birefringent?
Yes
How to distinguish between uric acid and cystine crystals?
- Polarizing microscopy
- Uric acid polarizes light and cystine does not
ID the element
Calcium oxalate
octahedral
dihydrate most common form
ID the element
Calcium oxalate
rectangular
monohydrate
Looks like rice
ID the element
Calcium oxalate
dumbell
monohydrate
ID the element
Calcium oxalate
ovoid
monohydrate
Can calcium oxalate polarize light?
Yes, so can help distinguish from RBCs (don’t polarize light)
Major component of kidney stones
Calcium oxalate
Foods high in oxalic acid
- Asparagus
- Spinach
- Tomatoes
- Rhubarb
- Garlic
- Ascorbic acid
Pathologic conditions involving calcium oxalate
- Kidney stones
- Oxalic acid poisoning
- Liver disease
- Ethylene glycol (anti-freeze) poisoning
Which form of calcium oxalate crystal is most frequently associated with ethylene glycol poisoning?
Long, monohydrate form (can be confused with hippuric acid)
Hippuric acid pH and solubility
- Found in acidic urine, but also neutral or alkaline urine
- Soluble in alkaline and hot water
- Rare crystal
Hippuric acid crystals can be a sign of
Toluene exposure
Hippuric acid crystals associated with
Diets high in fruits/veggies high in benzoic acid
ID element
Hippuric acid (sharp ends)
Ammonium biurate crystals are also known as
“Thorny apples”
Ammonium biurate crystal solubility
Acetic acid and heat
Ammonium biurate crystal clinical significance
- Only significant if seen in freshly voided urine
- Usually artifact of old/improperly stored urine
What happens to ammonium biurate if you add acetic acid?
They convert to uric acid crystals
ID element
Ammonium biurate crystal
ID the element
Ammonium biurate crystals
Calcium carbonate solubility
Effervesces (bubbles) in HCl and acetic acid
Calcium carbonate crystals confused with
RBCs and yeast
ID the element
Calcium carbonate crystals (dumbell)
ID the element
Calcium carbonate crystals (spherical)
Calcium phosphate shape variations
- Large flat plates
- Rosette
- Wedge-shaped prisms
Calcium phosphate solubility
Dilute acetic acid
ID the element
Calcium phosphate (most common form)
ID the element
Calcium phosphate
ID the element
Calcium phosphate
Calcium phosphate clinical significance
May be associated with kidney stones
Triple phosphate solubility
Acetic acid
Does triple phosphate polarize light?
Yes
Triple phosphate formation
Bacteria split urea into ammonia and CO2 in alkaline urines
ID the element
Triple phosphate
Cystine solubility
- HCl
- NaOH
- NH4OH (ammonium hydroxide)
Does cystine polarize light?
No
Cystine clinical significance
- Cystinuria (metabolic disorder)
- Most freq cause of kidney stones in kids
Cholesterol solubility
Chloroform, ether
Does cholesterol polarize light?
Yes
ID the element
Cholesterol
Note notch on one or more corners
Cholesterol clinical significance
- Nephritis
- Nephrotic conditions
- Chyluria due to obstruction of lymph drainage
- Tumors
- Filariasis
- Lymph node enlargement
- Rarely seen
Cholesterol formation
Lipids getting refrigerated
Tyrosine frequency and color
- Very rare
- Colorless to yellow-brown
Tyrosine shapes
- Single, fine needles with sharp points
- Sheaves
- Rosettes
Tyrosine clinical significance
- Severe liver disorders
- Inherited aa metabolism disorders
- Frequently seen with leucine crystals
Chemical strip test result if tyrosine present
Bilirubin positive bc Tyr crystals in liver damage
ID the element
Tyrosine crystals
Leucine appearance
- Yellow-brown spheroids
- Concentric rings
Chemical strip test result if leucine present
Bilirubin positive
ID the element
Leucine crystal
Leucine crystals confused with
Sulfonamide crystals
Bilirubin crystal appearance
- Yellow-brown needles or granules in clumps
- Sometimes attached to cells
Bilirubin crystal clinical significance
- Severe liver disorders
- Jaundice
ID the element
Bilirubin crystal
Radiographic dye appearance
Mostly flat needles or sheaves
Radiographic dye may be confused with
- Cholesterol
- Tyrosine
- Sulfonamides
How does radiographic dye affect the physical properties of urine?
Very high specific gravity (>1.035)
Note that chemical reagent strips only detect ionic solutes so radiographic dye not detected. Use refractometer to detect
Does radiographic dye polarize light?
Yes
Sulfonamide appearance
- Flat needles
- Sheaves of small needles
- Spheroids
- Brown
ID the element
Sulfonamides
ID the element
Sulfonamides
Sulfonamides confused with
Tyrosine, radiographic dye, leucine
Sulfonamide clinical significance
- Seen in pt taking sulfonamide abx
- May crystallize if not adequately hydrated -> nephron tubular damage and/or kidney stones
Acyclovir crystals
- Anti-viral medication
- Confused with tyrosine crystals
ID the element
Acyclovir crystals
Ampicillin crystals seen when
Pt is receiving large ampicillin doses without adequate hydration
ID the element
Ampicillin crystals
ID the element
Ampicillin crystals
Artifacts seen when
- Urine is improperly collected or in unclean containers
- More common in pediatric or nursing home patients
Are artifacts reported?
No
Only reported if gross contamination prevents proper analysis
List artifacts found in urine
- Talcum powder
- Starch
- Oil droplets
- Air bubbles
- Pollen
- Hair/cloth fibers
- Fecal contamination
ID the element
Talcum powder (artifact)
ID the element
Starch
How to distinguish starch from RBCs?
Polarized light
Starch shows pseudo-maltese cross
ID the element
Starch under polarized light microscopy
Characteristic pseudo-maltese cross
ID the element
Oil droplet artifact
ID the element
Air bubble artifact
ID the element
Pollen artifact
Hair and cloth fibers mistaken for __
Distinguish by __
- Casts and parasites
- Fibers are refractile whilst casts are not
Fecal contamination seen when
- Urine improperly collected (infants)
- Fistula between intestinal and urinary tracts