Red blood cells (RBC): 7µ in diameter, smooth, no nuclei (arrowheads). Normal urine
should not have > 0-2/HPF (high power field). White blood cells (WBC): spherical (1012µ) dull gray, characteristic granules and lobulations of the nucleus (arrow). Normal
urine should not have > 0-4/HPF
Red blood cells usually lyse in dilute, alkaline or "non-fresh" urine ("ghost" or "shadow"
cells). They crenate in hypertonic urine. Changing the microscope focus causes RBCs to
appear as black circles
Unlike RBCs (arrow), yeast cells are ovoid, variable in size, have double contour and are
frequently budding.
Dysmorphic RBCs (arrows): RBCs become dysmorphic when they travel through the
nephron length. Therefore, they indicate renal parenchymal disease (i.e., GN). They
usually appear as blebs or budding structures (dumbbell shape), better seen by phase
contrast lenses.
Dysmorphic RBCs (arrows): RBCs become dysmorphic when they travel through the
nephron length. Therefore, they indicate renal parenchymal disease (i.e., GN). They
usually appear as blebs or budding structures (dumbbell shape), better seen by phase
contrast lenses.
Note the numerous WBC and bacteria
Renal tubular epithelial cells: slightly larger than WBCs and contain a large round
nucleus (frequently eccentric). They may be cuboidal, columnar or teardrop-shaped (or
having tail-like projections). Seen in patients with ATN, exposure to heavy metals or
aminoglycosides.
Urinary casts are formed as a result of precipitation or gelation of Tamm-Horsfall
mucoprotein (secreted by renal tubules) and the clumping of cells or other materials
within the protein matrix. Therefore, their presence in the urine locates the pathology in
the renal parenchyma.
Urinary casts are formed as a result of precipitation or gelation of Tamm-Horsfall
mucoprotein (secreted by renal tubules) and the clumping of cells or other materials
within the protein matrix. Therefore, their presence in the urine locates the pathology in
the renal parenchyma.
As urinary casts travel through the nephron, they lose their cellular structures and become
granular (coarse or fine)
Hyaline casts are acellular seen in concentrated urine, after exercise and in patient with
proteinuria
RBC casts are usually seen in patient with glomerulonephritis or vasculitis. Rarely, in
patients with interstitial nephritis
WBC casts are usually seen in patients with pyelonephritis
Renal tubular cell casts are usually seen in patients with ATN. Note the single large
nucleus (arrow) which differentiates tubular cells from WBC.
Granular casts are degenerated cellular casts. This low power field (LPF) slide is typical
of ATN.
Calcium oxalate crystals are square with diagonal lines, "envelope” (short arrows).
They are colorless and vary in size. They can be found in the urine of normal people after
ingestion of oxalate-rich foods (tomatoes, spinach, oranges, asparagus, garlic and
rhubarb). They can also be seen in patients with calcium oxalate calculi, ethylene glycol
intoxication and following large doses of vitamin C.
Calcium oxalate crystals are seen in acidic urine.
Uric acid crystals can be seen in normal people. They can also be seen in patients with
gout, acute febrile illness, Lesch-Nyhan syndrome or tumor lysis syndrome. They have
various forms; rhomboid, star-shaped or whetstone shape.
Uric acid crystals are seen in acidic urine
Cystine crystals are hexagonal and colorless. They are Present in patients with
cystinuria.
Cystine crystals are seen in acidic urine.
Ammonium Magnesium Phosphates (Triple Phosphates, Struvite): the "coffin-lid."
They are usually associated with UTI by urease-producing organism (i.e., Proteus
mirabilis).
Triple phosphate crystals are seen in alkaline urine.