This document provides details on microscopic examination of urine sediment. Key points include: - Urine sample collection and preparation for examination under microscope by centrifuging and examining the sediment. - Classification of findings as organised or unorganised substances, and types of cells, casts, crystals and other formed elements that may be observed. - Significance of various normal and abnormal findings in identifying renal and other diseases. Detailed morphology of different cell types, casts, crystals and other structures are described.

1. Microscopic examination
of urine
-Dr Aarthi KB

2. Sample collection
 Mid-stream fresh first morning sample
because it is well concentrated.
 Urine examination to be done immediately
or within 2 hours of sample collection

3. Method of examination
 10-15 ml urine sample centrifuged for 5-10
min at 2000-3000 rpm.
 Supernatant is poured off.
 Tube tapped at bottom to resuspend the
sediment.
 A drop is placed on the slide and covered
with a cover slip
 Examined under microscope in high
power(40x)

5. Classification
 Organised
 Unorganised

6. Organised substances

7. Unorganised substances
 Crystalline
 Amorphous material

10. Cells
Erythrocytes:
 Pale biconcave discs about 7 mum in diameter.
 Unfresh specimen-shadow cells(faint and
colourless)
 In hypertonic urine-crenated
 In dilute urine-ghost cells
 0-2/hpf is normal

13.  Dysmorphic red cells:
RBCs with cellular protrusions or fragmentations
>80% dysmorphic red cells suggests glomerular pathology.

14. Renal diseases:
Glomerulonephritis
Lupus nephritis
Tb
Tumor
Renal vein thrombosis
Hydronephrosis
Polycystic kidney disease

15. Lower urinary tract diseases:
Acute and chronic infection
Calculus
Tumour
Hemorrhagic cytitis

16. Drugs:
Sulphonamides
Anticonvulsants
Salicylates
methenamine

17. Extra renal diseases:
 Acute appendicitis
 Malaria
 Sub Acute Bacterial Endocarditis
 Pan Arteriosus Nodosa

18.  Scurvy
 Tumours of colon rectum pelvis
 Salphingitis
 Diverticulitis

19. WBC
Neutrophils:
 Granular spheres,12mum in dia,multilobed nuclei
 Clumps-infections
 Many white cells in urine is pyuria.
 In hypotonic urine white cells are swollen,granules are
highly refractile and show brownian movement called
glitter cells.

21.  <5/hpf-normal
 >10/hpf or presence of clumps-UTI
 Increased pus cells seen in
1. Fever
2. Pyelonephritis
3. Tubulointerstitial nephritis
4. Renal transplant rejection
White cells+casts-renal infection(pyelonephritis)

22. Eosinophils
 >1%-acute interstitial nephritis
 Appreciated in Wright’s staining.
 Small lymphocytes and histiocytes-renal transplant
rejection and chronic inflammation

24. Epithelial cells
Squamous epithelial cells:
 Lines lower urethra and vagina
 Most frequent epithelial cells in normal urine and
least significant
 Cells are large and flat with abundant cytoplasm
and small round central nuclei.
 Large number of cells indicate contamination by
vaginal fluid.

26. Transitional (urothelial) cells:
 Lines renal pelvis, ureters, urinary bladder and
upper urethra.
 Smaller than squamous cells.
 Round or pear shaped (caudate cells) with centrally
located nucleus
 Large clumps or sheets seen in transitional cell
carcinoma.

29. Renal tubular epithelial cells:
 Similar in size as white blood cells
 Polyhedral,have granular cytoplasm
 Large eccentric refractile nucleus seen.

30.  Increase number seen in tubular damage:
1. Acute tubular necrosis
2. Pyelonephritis
3. Viral infections of kidney
4. Salicylate poisoning
5. Allograft rejection

33. Oval Fat bodies:
 Are tubular cells that have absorbed lipoproteins from
glomeruli
 Cholesterol - exhibit maltese cross under polarised light
 Triglyceride- Oil red O or Sudan III is required.
 Presence of these along with proteinuria=nephrotic
syndrome.

35. Telescoped urinary sediment
 Sediment consists of rbc,wbc,oval fat bodies and all
types of casts.
 Seen in
1. Lupus nephritis
2. Malignant hypertension
3. Rapidly progressing Glomerulonephritis
4. Diabetic glomerulonephritis

36. Casts
 Formed elements of urine that have kidney as their
origin
 Tamm-horsfall protein-secreted by ascending loop
of henle.
 All are hyaline. various types formed when
different elements get deposited on the hyaline
material.

38. Types
 Cellular-
1. RBC,
2. WBC,
3. Renal tubular epithelial cells

39.  Non-cellular:
1. Hyaline,
2. Granular,
3. waxy,
4. fatty

40. Non-cellular casts
Hyaline casts:
 Homogenous,colourless,refractile
 Cylindrical with parallel sides and blunt ends
 Increased numbers-cylinduria
 Composition-Tamm horsfall protein

41.  Increased numbers seen in
1. Glomerular nephritis
2. Chronic pyelonephritis
3. Congestive heart failure
4. Transiently increased in-
exercise,fever,heat exposure

43. Granular casts:
 Presence of cellular debri in a cast makes it granular in
appearance
 Cylindrical structures with coarse and fine
granules(degenerated renal tubular epithelial cells)

44.  Seen in:
1. nephrotic syndrome,
2. Lead toxicity
3. acute glomerulonephritis,
4. pyelonephritis

45. Granular casts

46. Waxy casts:
 Formed when hyaline casts remain in tubules for a
prolonged period
 Homogenous smooth glassy appearance cracked or
serrated margins
 Light yellow in colour
 Seen in End stage renal failure.

48. Fatty casts:
 Cylindrical structures filled with highly refractile fat
globules
 Seen in nephrotic syndrome

50. Broad casts:
 Form in dilated distal tubules
 Seen in chronic renal failure and severe tubular
obstruction
 Waxy and broad casts-worst prognosis

51. Cellular casts
 Casts contains at least three cells in matrix
Red cell casts:
 Cylindrical structures,appear brown due to hemoglobin
pigmentation
 Seen in acute glomerulonephritis
Ig A nephropathy
lupus nephritis etc.

53. White cell casts:
 Cylindrical structures with white blood cells embedded
in Tamm-horsfall protein.
 Refractile and exhibit granules
 Multi-lobed nucleus

54.  Seen in
1. pyelonephritis,
2. interstitial nephritis,
3. lupus nephritis.

56. Renal tubular epithelial cell casts:
 Singular rounded nuclei.
 Seen in acute tubular necrosis,
viral renal disease,
heavy metal poisoning,
acute allograft rejection.
 Even occasional finding is significant.

59. Crystals
 Formed by precipitation of urinary salts due to
alterations in pH,temperature and concentration.
 They can be
1. Normal
2. Abnormal

60. Normal crystals
 Crystals in acid urine:
a. Uric acid crystal:
Variable in shape-diamond,barrel,plate-like and hexagonal
Yellow or red-brown in colour
Increased number-gout and leukemia

62. b.Calcium oxalate crystals:
 Colourless,refractile and enveloped-shaped.
 Ingestion of tomatoes, spinach, cabbage, asparagus may
cause increase in number.
 Large number seen in ethylene glycol poisoing

65. c.Amorphous Urates:
 Urate crystals of potassium,magnesium or calcium in
acid urine
 Yellow fine granules

67.  Crystals in alkaline urine:
1.Calcium carbonate crystals:
 Small colourless and in pairs.
 Gives bubbles when they dissolve
 Round in shape with radial striations.

69. 2.Phosphate:
 Occur as crystals or as amorphous deposits
o Triple phosphates(Ammonium magnesium phosphates):
 Struvite stones.
 Coffin lid appearance
 Seen in UTI patients caused due to Proteus mirabilis.

71. o Calcium hydrogen phosphate(Stellar Phosphate)-Brushite
stones
 Colourless and variable shapes seen.
 Star,plates,prisms

72. 3.Ammonium Urate crystals:
 Appear as cactus like thornapple crystals
 Yellow-brown

74. Abnormal crystals
 Occur in acidic pH
 Additional chemical tests are to be done for
confirmation.
1.Cystine crystals:
 Colourless,hexagonal,
 Seen in cystinuria
 Associated with formation of cysteine stones.

76. 2.Cholesterol crystals:
 Colourless,refractile,rectangular plates with notched
corners.
 Seen in nephrotic syndrome and hypercholesterolemia

77. 3.Bilirubin crystals:
 Small brown crystals
 Square,bead-like or fine needle in shape
 Seen in severe obstructive liver diseases

78. 4.Leucine crystals:
 Refractile,yellow-brown sphere with radial or concentric
striations
 Seen with tyrosine crystals in severe liver
disease(cirrhosis)

79. 5.Tyrosine crystals:
 Clusters or fine delicate,
 Colourless or yellow needles
 Seen in liver disease,tyrosinemia.

80. 6.Sulfonamide crystals:
 Seen as sheaves of needles.
 Occur following sulphonamide therapy.

81. Abnormal cells and formed elements
 Tumour cells:
 Exfoliated Malignant cells
 Myeloma cells

82.  Bacteria:
 Gram stain bacteria more than 100000/microlitre-
significant bacteriuria.

83.  Fungi:
 Yeasts commonly seen in UTI of diabetic patients
 Confused with RBC

84.  Parasite:
 Trichomonas vaginalis may occur due to
 Vaginal contamination
 Urethral and bladder infection
 Identified by its motility.

86. Contaminants and artifacts
 Muscle fibres
 Pollen grains
 Starch granules
 Spermatozoa