1. MICROSCOPIC URINALYSIS
URINARY SEDIMENTS
Importance
 integral part of the urinalysis (UA).
 Sediment findings often are necessary for the proper interpretation of results of the
physicochemical portion of the UA
 Detect and identify insoluble materials in the urine.
Limitations
 Least standardized
 Time consuming
 Expensive
 Requires Technical expertise
“ The decision to perform microscopic examinations should be made by each individual laboratory based
on its specific patient population.”
-CLSI
Specimen consideration
 Fresh or adequately preserved
 Mid-stream clean catch
 First morning specimen
 Thoroughly mixed
VOLUME:
 10-15 mL
 Indicate if lesser volume is used
 Correct for volumes
Specimen Centrifugation
 5 minutes
 400 RCF (relative centrifugal force)
 Braking mechanism is not recommended
SEDIMENT PREPARATION
 0.5 – 1.0 mL
 Aspirate off the supernatant
 Thorough resuspension of the sediment
SEDIMENT VOLUME:
 20 uL (0.02 mL)
 Cover slip overflow of sediment not allowed
RCF
 Centrifugal force – how many times greater than gravity
- expressed as relative centrifugal force (RCF) or g

2. - depends on three variables
i. speed- expressed as revolutions per minute (rpm)
**related to RCF by the following equation:
RCF = 1.118 x 10-5 x r x (rpm)2
ii. mass
iii. radius(r)- measured from the center of the centrifugal axis to the bottom of the test tube shield.
Constituents of urine sediment
 Organized sediment – biological source
 RBC
 WBC
 Epithelial cells
 Fats
 Casts
 Bacteria
 Yeast
 Fungi
 Parasite
 spermatozoa
 Unorganized sediment
chemical source
 Normal acid crystals
 Normal Alkaline crystals
 Abnormal crystals of metabolic origin
 Abnormal crystals of iantrogenic origin
Red Blood Cells (RBC)
 Smooth, non-nucleated, biconcave disk
 7 um in diameter
 Examined under HPO
 Reported as average in 10 HPFs
Variations:
1. Crenated – found in concentrated urine
2. Ghost cells – cell membrane found in dilute urine
3. Dysmorphic – cells of varying sizes, have cellular protrusions or are fragmented
Normal and Crenated RBC

3. Normal and Dysmorphic RBC
Clinical Significance
 Damage to the glomerular membrane
 Vascular injury within the genito-urinary tract
 Increased following strenuous exercise
 Contamination with menstrual blood
GROSS HEMATURIA:
 Advanced glomerular damage
 Trauma damaging vascular integrity
 Acute inflammation and infection
 Coagulation disorder
White Blood Cells (Neutrophils)
 Larger than RBCs measuring 12 um in diameter.
 Predominantly neutrophils
 Contains granules and multi-lobed nuclei
 Reported as average number per 10 hpf
 “Glitter Cells” – disintegrated neutrophils
 Easily lyses in dilute alkaline urine

4. Uncommon WBC
Eosinophils – associated with drug induced interstitial nephritis, UTI and renal transplant rejection
 Reported as a percentage in 100 to 500 WBC
 1 % eosinophil is significant
 Preferred stain – Hansel
Mononuclear Cells – increased in the early stages of transplant rejection
 Appears vacuolated and contains inclusions
 Diagnosed by cytocentrifugation and Wright’s stain
Clinical Significance
Pyuria – increase in urinary WBCs
 Indicates:
-infection or inflammation in the genitourinary system
-Bacterial infection: pyelonephritis, cystitis, prostatitis and urethritis
-Non-bacterial disorders – glumerulonephritis, LE, Interstitial nephritis and tumors
Epithelial Cells
 Represents the normal sloughing of old cells
 Clinically insignificant in small numbers
 May be contamination from the genitalia

5.  Three types are seen in urine classified according to their site of origin in the genitourinary
tract.
- Squamous epithelial cells
- Transitional epithelial (Urothelial) cells
- Renal Tubular Epithelial Cells
Squamous epithelial cells
 Largest cells found in the urine sediment
 Contains abundant cytoplasm with a prominent nucleus
 Originates from the linings of the vagina and female urethra and the lower portion of the male
urethra.
 No clinical significance
 Usually increased in females
 Reported in words as rare, few, moderate or many
Clue Cells
 Indicates infection vaginal infection with Gardnerella vaginalis
 Squamous cells covered with the bacteria

6. Transitional Epithelial Cells(Urothelial)
 Smaller than squamous cells
 Appears in several forms (polyhedral, spherical, caudate) due to its ability to absorb water.
 Originates from the lining of the renal pelvis, calyces, ureters and bladder and the upper portion
of the male urethra
 No clinical Significance
 Increased in invasive urologic procedures such as catheterization
 Presence of vacuoles and irregular nuclei may indicate viral infection or malignancy
Renal Tubular Epithelial Cells
 The most clinically significant of the epithelial cells.
 Morphology varies depending on the site of origin
PCT – largest of the RTE, rectangular, coarsely granular cytoplasm.
DCT – smaller, round or oval, with eccentrically placed round nucleus
Collecting ducts – cuboidal, never round, eccentrically placed nucleus, one side is straight, appears
in sheets

7. RTE Clinical Significance
 Increase indicate necrosis of the renal tubules
- exposure to heavy metals
- drug induced toxicity
- hemoglobin and myoglobin toxicity
- viral infection
-pyelonephritis
- allergic reaction
- malignant infiltration
-salicylate poisoning
-acute allogenic transplant rejection
Oval Fat Bodies
 RTE cells that absorb lipids present in the glomerular filtrate
 Highly refractile
 Seen along with free-floating fat droplets
 Stains well with Sudan III and Oil Red O
 Composed of triglycerides, neutral fats and cholesterol
 “Maltese Cross” – observed in the presence of cholesterol under polarized light

8. Maltese Cross
Casts
 Unique to the kidney
 Most difficult to recognize and most important sediment
 Represent a biopsy of the tubules
 Must be observed under subdued light because of the low refractive index of the cast matrix
 Reported as the average number in 10 lpfs
 Disintegrates in dilute alkaline urine.
Composition of Casts
 Major constituent: Tamm-Horsfall protein
 The glycoprotein gels easily under conditions of urine stasis,
acidity and the presence of sodium and calcium
 Width of the cast depends on the size of the tubule
Cast Formation
 Formed in the lumen of the DCT and collecting ducts

9. Hyaline Cast
 The most commonly seen cast in the urine
 Consist almost entirely of Tamm-Horsfall protein
 Colorless, homogenous, non-refractive, semi-transparent
 0-2/lpf is normal
 Seen in strenous exercise, dehydration, heat exposure, and emotional stress
 Increased in acute glomerulonephritis, pyelonephritis, chronic renal disease and congestive heart
failure

10. RBC Cast
 Indicates bleeding within the nephron
 Primarily associated with damage to the glomerulus.
 Also associated with proteinuria and dysmorphic RBC
 Orange-red in color
 Dirty brown cast indicates hemoglobin degradation and associated with acute tubular necrosis.

11. WBC Casts
 Indicates infection or inflammation within the nephron.
 Associated with pyelonephritis and differentiates upper UTI from lower UTI
 Also seen in acute interstitial nephritis and glomerulonephritis.
 Appears granular and multilobed

12. Epithelial Cell Casts
 Contains RTE cells
 Indicates advanced tubular destruction
 Seen in heavy-metal and drug induced toxicity, viral infections, allograft rejections and
pyelonephritis.
Fatty Casts
 Associated with oval fat bodies and free fat droplets in cases of lipiduria
 Indicates nephrotic syndrome, toxic tubular necrosis, DM and crush injuries
 Highly refractile, confirmed with Sudan III and Oil Red O using polarized light

13. Mixed Cellular Casts
 Contains more than one type of cell
 Usual combinations: WBC and RBC in glomerulonephritis, WBC and RTE or WBC and bacteria in
pyelonephritis
Makes identification difficult
Granular Casts
 May appear finely of coarsely
 Non-pathologic increase in strenuous exercise
 In diseases, it indicates disintegration of cellular casts

14. Waxy Casts
 Represents extreme urine stasis indicating chronic renal failure.
 Presents brittle, highly refractile cast matrix due to disintegration of hyaline and other cellular
components of the cast
 Appears fragmented with jagged edges and notches on their sides

15. Broad Casts
 Also referred to as renal failure casts
 Represents extreme urine stasis
 Indicates destruction of the tubular walls
 Commonly of the granular and waxy types.

16. Cast Formation
Other Casts
 Rare incorporation of other structures in the urine sediments
 Pigmented Casts – hemoglobin, myoglobin and certain drugs
 Hemosiderin casts
 Crystal casts – urates, calcium oxalates and sulfonamides
Cylindroids
 Resemble casts but have one end that tapers to a tail
 Found in conjunction with casts and have same significance

17. Mucus Threads
 Long thin waxy threads, very transparent
 Can be found in small number in normal urine
 Increased numbers indicate inflammation or irritation of the urinary tract
Bacteria
 Not normally seen in urine
 Results from vaginal, urethral, external genitalia or specimen container contamination
 Presents as cocci or bacilli
 Usually motile
 May Indicate UTI if seen in freshly voided urine and correlated with
WBCs
Yeast
 Small, refractile, oval structures which may show budding
 In severe in fections, mycelium may be seen
 Most common: Candida albicans

18.  Seen in DM, immunocompromised patients and women with vaginal moniliasis
 Accompanied by WBCs
Fungi
 In severe infections
 May include appearance of mycelium
Parasites
 Most frequent: Trichomonas vaginalis – pear shaped flagellate with undulating membrane
 In fresh wet preparations, usually motile with rapid darting movements

19.  Other parasites: Schistosoma haematobium, Enterobius vermicularis, other parasite contaminants
from the feces
T. vaginalis
S. haematobium
E. Vermicularis
Spermatozoa

20.  Oval, slightly tapered heads and long flagella like tails, usually non-motile
 Seen in urine of both female and male after intercourse and in male urine after masturbation and
nocturnal emission
 Not clinically significant except in cases of male infertility and retrograde ejaculation
 Also important in medico-legal cases
Urinary Crystals
 Formed by the precipitation of urine solutes
 Rarely of clinical significance
 Reported in words
 Identified in order to detect the few abnormal crystals
Crystal Formation
 In vivo factors include:
the concentration and solubility of crystallogenic substances contained in the specimen,
 the urine pH
 the excretion of diagnostic and therapeutic agents.
 In vitro factors include: temperature (solubility decreases with temperature),
 evaporation (increases solute concentration),
 urine pH (changes with standing and bacterial overgrowth).
Amorphous Urates
 Amorphous urates appear as aggregates of
finely granular material without any defining
shape
 Amorphous urates (Na, K, Mg, or Ca salts)
tend to form in acidic urine
 May have a yellow or yellow-brown color.
 Common in refrigerated specimens wit
pink sediments

21. Uric Acid
 May appears as Rhombic, foursided flat planes, wedges, and rosettes
 Usually yellow-brown but may appear colorless
 Highly birefrigent under polarized light
 Increased in high levels of purines and nucleic acids
 Seen in patients with leukemia undergoing chemotherapy, Lesch-Nyhan syndrome and gout
Calcium Oxalate Dihydrate
 Calcium oxalate dihydrate
crystals typically are seen as
colorless squares whose
corners are connected by
intersecting lines (resembling
an envelope).
 They can occur in urine of any
pH.
 The crystals vary in size
from quite large to very
small.
 In some cases, large
numbers of tiny oxalates may
appear as amorphous unless
examined at high
magnification.

22.  Increased in high intake of oxalic acid and ascorbic acid
Calcium Oxalate Monohydrate
 Less frequently seen
 Oval or dumbbell shaped
 Birefrigent
 Indicates ethylene glycol poisoning
Normal Crystals seen in neutral to alkaline urine
 Amorphous phosphate
 Triple Phosphate
 Calcium Phosphate
 Calcium Carbonate
 Ammonium Biurate
Amorphous Phosphates
 Morphologically resemble amorphous urates
 Increased in refrigerated sample but gives a white color
 Can be differentiated from urates by the pH of the urine and its non-dissolution on warming.

23. Triple Phosphate, Struvite,
Ammonium Magnesium phosphate
 appear as colorless, 3-dimensional, prism-like crystals ("coffin lids").
 Occasionally, they instead resemble an old-fashioned double-edged razor blade
 Birefrigent on polarized light

24. Calcium Phosphate
 Colorless
 Shape: long, thin prisms with one pointed and arranged as rosettes or clusters of needles
 Thin irregular plates that float on surface of urine
 Associated with renal calculi
 Dissolves in dilute acetic acid
 May be confused with sulfonamide crystal

25. Calcium Carbonate
 Calcium carbonate crystals usually appear as large yellow-brown or colorless spheroids with radial
striations.
 They can also be seen as smaller crystals with round, ovoid, or dumbbell shapes
 Liberates gas on addition of acetic acid
Ammonium Biurate
 Color: yellow to brown
 Shape: Spherical bodies with long irregular spicules
 Often described as thorn- apple
 Associated with the presence of ammonia from urea-splitting bacteria
 Soluble in acetic acid and Heat
Abnormal Urine crystals of Metabolic Origin
 Seen in acidic to neutral urine
 Requires chemical confirmation
- Cystine
-Tyrosine

26. -Leucine
-Cholesterol
- Bilirubin
Cystine
 Colorless, refractile, hexagonal plates that are often laminated
 Seen in patients with cystinuria
 Disintegrates in alkaline urine
 Soluble in ammonia and dilute HCl
 Confirmed by the cyanide nitroprusside reaction
Tyrosine
 Colorless, fine, silky needles arranged in sheaves or clumps
 Seen in hereditary tyrosinosis, oasthouse urine disease and with leucine in massive liver failure
 Confirmed by the nitrosonaphthol test or HPLC

27. Leucine
 Yellow, oily looking spheres with radial and concentric striations
 Extremely rare
 Seen in severe liver damage with tyrosine

28. Cholesterol
 Color: transparent
 Shape: regular to irregular flat plates with one corner notched out, may be single or in larger
numbers
 Most often found after refrigeration
 Indicates Excessive tissue breakdown
 Seen in nephritis and nephritic syndrome
 Soluble in chloroform
Bilirubin
 Bilirubin crystals tend to precipitate onto other formed elements in the urine.
 fine needle-like crystals can form on an underlying cell. This is the most common appearance of
bilirubin crystals.

29.  cylindrical bilirubin crystals can form in
association with droplets of fat, resulting in a
"flashlight" appearance. This form is less
commonly seen.
 Seen in Obstructive jaundice
 Bilirubin must be present in urine
Abnormal Crystals of Iantrogenic origin
 Caused by increased amount of drugs

30.  Important because of the likelihood of renal damage and bleeding leading to renal failure
-Sulfonamides
-Ampicillin
-Radiographic contrast media
Sulfonamides
 Color: brown to yellow
 Shape: needle-like shapes seen in bundles or
sheaves; Stacks of wheat
 Common forms: sulfamethoxazole,
acetylsulfadiazine and sulfadiazine
Ampicillin
 Long, thin, colorless needles in acidic urine
 Very rarely seen
 Seen in Administration of large parenteral doses

31. Radiographic contrast media
 Color: opaque , appear dark and thick
 Shape: pleomorphic needles, single or sheaves
 May be mistaken for cholesterol crystals
 Significant in elderly patients
 Intravenous injection for radiography Can appear up to 3 days after injection
Contaminants and Artifacts
 Usually easy to see
 Causes distraction on the observer
- Starch
-Fibers
-Air bubbles

32. -Oil droplets
-Glass Fragments
- Stains
- Pollen grains
- Fecal contamination