urine microscopy

1. MICROSCOPIC EXAMINATION OF
URINE
Dr.Sandeep Singh
Pathologist

2. PREPARATION OF SEDIMENT
 Take 5-10 ml of urine in a centrifuge tube.
 ii. Centrifuge for 5 minutes at 3000 rpm.
 iii. Discard the supernatant.
 iv. Resuspend the deposit when about one ml
of urine left and shake it well.
 v. Place a drop of this on a clean glass slide.
 vi. Place a cover slip over it and examine it
under the microscope . This is done by
keeping the condense low .

3.  Following constituents are frequently
reported in the urine on microscopic
examination:
 1. Cells ( RBC’s, WBCs, epithelial cells)
 2. Casts
 3. Crystals
 4. Miscellaneous structures

4. Cells in urine:
 Red Blood Cells (RBCs)
 These appear as pale or yellowish , biconcave,
double contoured, disc like structures, and when
viewed from side they have an hourglass
appearance. In hypotonic urine, RBCs swell up
while in hypertonic urine they are crenated.
 Significance . Normally no or occasional RBCs
are passed in urine, RBCs in excess of this
number are seen in urine in the following
conditions of urinary tract.:
 1. Glomerular diseases-Glomerulonephritis,
lupus nephritis.
 2. Non glomerular diseases -
Calculus,tumour,infection,tuberculosis,pyelonephri

6. White blood cells (WBCs)
 These appear as round granular 10-15 µ in
diameter. In fresh urine nuclear details are well
visualized. WBCs can be confused with RBCs.
For differentiating add a drop of dilute acetic acid
under coverslip. RBCs are lysed while nuclear
details of WBCs become more clearer.
 Significance: normally 0-2 WBCs/ HPF may be
present. WBC cells greater than 10/ HPF is
suggestive of urinary tract infection. Simultaneous
presence of white cells and white cell casts
indicates presence of renal infection. Increased
numbers of WBCs occur in:
 Fever, pyelonephritis, lower urinary tract infection,
tubulo interstitial nephritis and renal transplant
rejection.

8. Epithelial Cells
 These are round to polygonal cells with a round to
oval, small to large nucleus. Epithelial cells in
urine can be squamous epithelial cells, tubular
cells and transitional cells, i.e. they can be from
lower or upper urinary tract
 Significance-Normally few squamous epithelial
cells are seen in normal urine, more common in
females, and reflect normal sloughing of these
cells.
 Presence of renal tubular epithelial cells is a
significant findings. Increased numbers are found
in conditions causing tubular damage

10. CASTS IN URINE
 These are formed due to moulding in renal
tubules of solidified proteins
 . In general, casts are cylindrical in shape with
rounded ends. The basic composition of casts is
tamm- Horsfall protein which is secreted by
tubular cells. appear renal diseases.
 Casts are of two main types:
 Noncellular cast: Hyaline, Granular, Waxy,
fatty.
 Cellular cast: RBC cast, WBC cast, Epithelial
cell cast


11. Cast:
 Hyaline Most common Hyaline cast is basic protein cast. These are
cylindrical, colourless homogeneous and transparent. seen in increased
numbers after strenuous exercise in healthy persons during dehydration
or diuretic medicines.
 Granular Casts: Granular casts have coarse granules in basic matrix.
suggests stasis in the nephron. After strenuous exercise, Pyelonephritis,
Acute tubular necrosis.
 Waxy Casts: Waxy cast represent the final stage of degeneration of
cellular cast. Waxy casts are yellowish homogeneous
 Fatty Cast: Fatty casts are formed by the breakdown of lipid rich epithelial
cells.They contain fat globules of varying size
 RBCs Cast: These casts contain RBCs and have a yellowish orange
colour . Glomerular damage result in appearance of RBCs into tubules.
RBC cast usually denote glomerular pathology.
 WBC Cast: These contain granular cells (WBCs , generally neutrophils) in
a clear matrix.

13. CRYSTALS IN URINE
 Crystals are refractile structures with a definite
geometric shape. and appearance of crystals in urine
depend upon pH of the urine . i.e acidic or alkaline.
 Normal Crystal in Acidic Urine:
 i.Calcium Oxalate: These are colourless refractile and
have octahedral envelope-like structure . They can also
be dumb- bell shaped. Ingestion of certain foods like
tomatoes, spinach, cabbage, causes increased number.
 ii. Uric Acid: They are yellow or brown rhomboid
shaped seen singly or in rosettes. They can also be in
the form of prism, plates and sheaves. Increased
number seen in gout and leukaemia.

14.  Normal Crystal in Alkaline Urine: These
are as under: Amorphous Phosphate, Triple
phosphate.
 ii. Triple phosphate: They are in the form of
prisms and sometimes in fern leaf
pattern. They dissolve when urine is made
acidic.
 iii. Calcium carbonate: They are in the form
of granules, spheres or rarely dumb-bell
shaped. They again dissolve acidic in urine.
 iv. Ammonium biurate: They are round of
oval yellowish brown spheres with thorns
on their surface giving thorn apple

15.  Abnormal rare crystals:
 i. Tyrosine crystal: They are yellowish in the form of
silky needles or sheaves. They are passed in urine in
liver disease and tyrosinemia.
 ii. Cystine crystal: They are colourless, hexagonal
plates which are highly refractile. They are passed in
urine in an inborn error of metabolism .
 iii. Cholesterol Crystals: They are seen in lipiduria.e.g.
Nephrotic syndrome and hypercholesterolemia.
 iv. Sulphonamide crystal: They appear as yellowish
sheaves rosettes, or rounded with radial striation..
 v. Bilirubin crystal: Seen in severe obstructive liver
disease.
 vi. Leucine crystal: Leucine crystals indicate a problem
with the metabolism of the amino acid leucine.

17.  Amorphous material has no definite shape
and is commonly seen in the form of
granular clumps.