Urine Sediments Flashcards
Microscopic UA
- Recommended volume
10-15 mL (12mL is preferred)
Microscopic UA
- Centrifugation time
5 minutes
Microscopic UA
- Centrifugation speed
400-450g (1800 rpm)
Procedure for preparing a specimen for sediment examination
- Mix specimen and pour aliquot of 10-12 mL into urine urine centrifuge tube
- Centrifuge for 5 minutes at 400-450g
- After coming to a complete stop, decant the tube
- Mix remaining sediment well
- Deliver well mixed sediment to the slide using disposable pipet
Proper magnification for enumerating casts
Low (10x) but identify at High (40x)
Proper magnification for enumerating mucus
Low (10x)
Proper magnification for identifying and enumerating epithelials, WBCs, RBCs, crystals
High (40x)
Proper magnification for evaluating the presence of bacteria, sperm, yeast, trichomonas, or other
High (40x)
How do RBCs act in hyper/hypotonic urine?
- Hypertonic: crenate
- Hypotonic: swelled, lysed, or ghost cells (includes alkaline urine)
RBCs will lyse in ____ ____
Acetic acid
____ indicates damage to the kidney or urinary tract
Hematuria
RBCs/RBC casts/protein indicate what?
Renal origin, either glomerular or tubular
- Glomerulonephritis
- Pyelonephritis
- Tumors
- Calculi
- Trauma
RBCs/no RBC casts/no protein indicate what?
Bleeding “below” the kidney (cystitis) or contamination (menstrual or hemorrhoidal)
T/R, hemoglobin levels < 250 RBCs/uL are likely to cause a positive protein
False
If RBCs are seen microscopically but not on the strip, what does that mean?
- Expect interference w/ ascorbic acid
- Possible misidentification of RBCs
How do WBCs act in hyper/hypotonic urine?
- Hypertonic: will shrink but won’t crenate
- Hypotonic: will enlarge and may lyse
What do degenerated WBCs look like?
- Lyse
- Bleb formation
If pyuria is seen w/ WBC casts, cellular casts, or granular casts, this indicates what?
Upper UTI is suspected; positive protein
If pyuria is seen w/o casts, this indicates what?
Lower UTI is suspected; low protein
What does the predominance of eosinophils indicate?
- Drug induced acute interstitial nephritis
- Renal transplant rejection
What does the predominance of lymphs indicate?
Early renal transplant rejection
Leukocyte esterase strip detects ____ and ____ WBCs
Intact; lysed
What is a glitter cell?
Swollen neutrophils in a hypotonic solution
What makes a swollen neutrophil a glitter cell?
Their refractile cytoplasmic granules move by Brownian movement and “glitter”
How do you differentiate RBCs from yeast?
Yeast varies in size, is not biconcave, and buds
How do you differentiate RBCs from air bubbles/oil droplets?
Air bubbles/oil droplets are refractile, vary in size, and have a uniform appearance
How do you differentiate RBCs from calcium oxalate crystals?
Calcium oxalate crystals have an envelope shape
How do you differentiate RBCs from starch?
Starch is not perfectly round, highly refractile, has a central dimple, maltese cross under polarized light
Squamous epithelial cells
- Appearance
- Flat w/ irregular shapes
- Central round nucleus
Squamous epithelial cells
- Origin
Vaginal contamination
Squamous epithelial cells
- Clinical significance
Rare diagnostic significance
Transitional epithelial cells
- Appearance
- Round
- Pear-shaped or tail-like projection
- Central round nucleus
Transitional epithelial cells
- Origin
Originates in renal pelvis, calyces, ureter, urinary bladder, and upper part of urethra in males
Transitional epithelial cells
- Clinical significance
Increased numbers: UTI, viral illness, catheterization, malignancy (transitional cell carcinoma)
Sheets of transitional epithelial cells
Synctia
Presence of synctia w/o recent catheteriztion indicates what?
Transitional cell carcinoma
Renal tubular epithelial cells
- Appearance
- Polyhedral (flat, cuboidal, columnar)
- Eccentric nucleus
- BIG nucleus
Renal tubular epithelial cells
- Origin
Originate in lining of the renal tubules and collecting ducts
Renal tubular epithelial cells
- Clinical significance
MOST SIGNIFICANT EPI
- Pathologic → pyelonephritis, kidney damage from meds or toxins, tubular necrosis, renal transplant rejection, viral infections (Hep B)
Origin of an oval fat body
Renal tubular epi cell w/ absorbed lipids
Cholesterol
- Not/birefringent
Birefringent
Neutral fats (triglycerides, fatty acids) - Not/birefringent
Not birefringent
Cholesterol
- Stains
Does not stain
Neutral fats (triglycerides, fatty acids) - Stains
Sudan Red or Oil Red O (identification)
What is the difference b/w oval fat bodies, air bubbles/oil droplets, and starch granules?
- Starch: maltese cross pattern under polarized light; under normal light, not spherical, highly refractive, dimple in center
- Oils: refractive, vary in size, uniform appearance
Clinical significance of sperm found in urine
- Males: recent ejaculation or nocturnal emission
- Females: vaginal contamination
Normal acidic crystals
- Uric acid
- Amorphous urates
- Calcium oxalate
- Hippuric acid
- Monosodium urate
Abnormal acidic crystals (PATHOLOGIC)
- Tyrosine
- Leucine
- Bilirubin
- Cystine
- Cholesterol
- Sulfonamide
- Radiographic dye
Alkaline crystals (no abnormal crystals in alkaline urine)
- Amorphous phosphates
- Triple phosphate
- Calcium carbonate
- Calcium phosphates
- Ammonium biurates
Pathologic crystals appear in ____ and ____ pH
Acidic; neutral
Usually presented as rhomboid plates but can also be seen as six-sided plates or barrels; when multiple crystals laminate together, they form rosettes or stars; yellow-brownish in color
Uric acid crystals
Uric acid crystals
- Clinical significance
- Normal, product from digestion of RNA and DNA
- Chemotherapy
- Gout
- Acute febrile conditions
- Chronic renal disease
- Lesch-Nyhan Syndrome
Yellow-brown, pink sediment; precipitation is enhanced on refrigerated specimens
Amorphous urates
Amorphous urate
- Clinical significance
No clinical significance
Pencile/needle-like prisms; colorless to light yellow
Monosodium urate crystals
Monosodium urate crystals
- Clinical significance
No clinical significance