Microscopic Examination Of Urine

This slide shows mucus in urine with two entrapped white cells. There are also two red cells present, one within the mucus and one above it

Budding yeast are visible on the left side of this slide with a squamous epithelial cell on the right

These "triple phosphate" crystals look like rectangles, or coffin lids

Triple phosphate crystals, resemble prisms or "coffin lids". They are found normally in alkaline or neutral urine. They are colorless

Tyrosine crystals are not normally found in urine. They are products of protein metabolism and appear in urine of people with tissue degeneration or necrosis (acute liver disease, severe leukemia, typhoid fever, and smallpox). They are present only when urine is acid. They are colorless to yellowish brown, needle shaped crystals and have a fine silky appearance.Tyrosine crystals usually appear in urinary sediment together with leucine crystals

Sulfonamide crystals form primarily in acid urine. The shape and color of these crystals are extremely variable, depending on the particular sulfonamide being administered to the patient

Leucine crystals are not normally found in urine They appear in urine in association with tyrosine and are manifestations of the same clinical conditions. When found, leucine crystals are in acid urine in the form of spheroids with concentric striations. They are dense, highly refractive and appear as yellowish brown bodies

Ammonium urate crystals are easily distinguished by their golden brown color and "thorn apple" shape. They are seen here under bright field microscopy .They are the only urate crystals that appear in alkaline urine

Uric acid crystals exhibit extreme pleomorphism in size and in shape. They appear readily in acid urine allowed to stand at room temperature

Cholesterol crystals are seen in the center of this field. They appear as regular or irregular transparent plates. They may occur singly or in large numbers. Usually one or more corners are cut off or notched, justifying their description as "stair step crystals". They are not commonly seen and are always considered pathological

Cystine, an amino acid, is an abnormal finding in urine. Rarely seen, these crystals are found in acid urine and are seen as thin, colorless, hexagonal plates

Calcium phosphate crystals assume various forms including the rosette and pointed finger forms shown here with bright field microscopy (160X magnification). They appear most often in alkaline urine

CALCIUM OXALATE

Amorphous phosphates appear in neutral to alkaline urine as fine, colorless or slightly brown granules. White precipitate is observed on centrifugation

Amorphous urates appear as fine pink or brownish-tan granules They are salts of uric acid and are normally found in acid or neutral urine

A group of attached renal tubular epithelial cells are seen in the center of this slide

Renal Tubular Cells (RTC) are originally cubic in shape; but once exfoliated, they adopt a rounded shape. These cells are slightly larger than leukocytes (10-14 um) with lightly granular cytoplasm. The nucleus is round, well defined and usually centric

Transitional epithelial cells originate from the renal pelvis, ureters, bladder and/or urethra. Most often they are round or polygonal. They are generally somewhat smaller and smoother in outline than squamous cells, but larger than WBC

This is a squamous epithelial cell under brightfield microscopy

Squamous epithelial cells are the largest cells seen in normal urine specimens. They are thin, flat cells, usually with an angular or irregular outline and a small round nucleus. They may be present as single cells or as variably-sized clusters

Note the irregular outlines of many of these RBC's, compared to two relatively normal RBC's at the center left of the right panel. These abnormal RBC's are dysmorphic RBC's

Red Blood Cells

White Blood Cells

Waxy cast

Fatty Cast

Finely granular cast in urinary sediment. A uric acid crystal is visible in the upper left corner of the fiel

Granular Cast

Granular Cast

Red blood cell cast with red cells concentrated at one end

Hyaline cast

MICROSCOPIC EXAM
In the urinalysis microscopic exam one looks for formed cellular elements, casts, bacteria, yeast, parasites and crystals in centrifuged urine sediment.
PROCEDURE
.... Centrifuge 5 mL of a mixed, freshly voided or catheterized urine in a conical centrifuge tube for 5 minutes at high speed
.... Remove supernatant
.... Resuspend the sediment by gently mixing
.... Place a drop of stained or unstained suspension on a slide
.... Place the slide on the microscope stage
DESCRIPTIONS OF MICROSCOPIC ELEMENTS
HYALINE CAST
Hyaline casts are formed in the absence of cells in the renal tubular lumen.
Have a smooth texture and a refractive index very close to that of the surrounding fluid
Hyaline casts are not always indicative of clinically significant disease
Greater numbers of hyaline casts may be seen associated with proteinuria of renal (eg., glomerular disease) or extra-renal (eg., overflow proteinuria as in myeloma) origin
RED BLOOD CELL CAST
Red blood cells may stick together and form red blood cell casts. Such casts are indicative of glomerulonephritis, with leakage of RBC's from glomeruli, or severe tubular damage
WHITE BLOOD CELL CAST
White blood cell casts are most typical for acute pyelonephritis, but they may also be present with glomerulonephritis. Their presence indicates inflammation of the kidney, because such casts will not form except in the kidney
GRANULAR CAST
Cellular casts remain in the nephron for some time before they are flushed into the bladder urine, the cells may degenerate to become a coarsely granular cast, later a finely granular cast, and ultimately, a waxy cast.
Granular and waxy casts are be believed to derive from renal tubular cell casts.
seen in end-stage chronic renal disease
FATTY CAST
Fatty casts are identified by the
Presence of refractile lipid droplets
The background matrix of the cast may be hyaline or granular
Often, they are seen in urines in which free lipid droplets are present as well Pictured is a fatty cast with a hyaline matrix
WAXY CAST
Waxy casts have a smooth consistency but are more refractile and therefore easier to see compared to hyaline casts. They commonly have squared off ends, as if brittle and easily broken. Waxy casts are found especially in chronic renal diseases, and are associated with chronic renal failure; they occur in diabetic nephropathy, malignant hypertension and glomerulonephritis
WHITE BLOOD CELLS
White Blood Cells (WBC) in unstained urine sediments typically appear as round, granular cells which are 1.5-2.0 times the diameter of RBCs. WBC in urine are most commonly neutrophils
Greater numbers (pyuria) generally indicate the presence of an inflammatory process somewhere along the course of the urinary tract . Pyuria often is caused by urinary tract infections
RED BLOOD CELLS
Hematuria is the presence of abnormal numbers of red cells in urine due to:
.... glomerular damage
.... tumors which erode the urinary tract
.... kidney trauma,
.... urinary tract stones,
.... upper and lower urinary tract infections,
.... nephrotoxins, and physical stress
RBC's may appear normally shaped, swollen by dilute urine or crenated by concentrated urine. Both swollen, partly hemolyzed RBC's and crenated RBC's are sometimes difficult to distinguish from WBC's in the urine
EPITHELIAL CELLS
Squamous epithelial cells are the largest cells seen in normal urine specimens. They are thin, flat cells, usually with an angular or irregular outline and a small round nucleus. They may be present as single cells or as variably-sized clusters
CALCIUM OXALATE
Calcium Oxalate 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.