Microscopic UA: Part 1, 2, 3 Flashcards
Describe the recommended methods for standardizing specimen preparation, volume, centrifugation, sediment preparation, volume and examination, and reporting of results.
Ask Caroline
State the purpose of Sternheimer-Malbin
delineates(portrays) nucleus and cytoplasm. Used for WBC, epithelial cells and casts (purple).
-It is a general purpose stain. The MOST COMMON stain for MICROSCOPIC sediment.
This stain consist of CRYSTAL VIOLET and SAFRANIN O.
True or False: Sternheimer-Malbin or Sedi-stain will not stain fat cells.
It will only stain specific elements and this is not one of them.
State the purpose of acetic acid
-Used to dissolve amorphous phosphates.
-Used to enhance nuclear detail of WBC
-WILL LYSE RBC’s, but not yeast or bacteria.
-Used to differentiate RBC from WBC, yeast, etc. (dissolves WBC granules) and to dissolve amorphous phosphates (to see bacteria).
State the purpose of toluidine blue
delineates nuclear detail. Used to differentiate WBC from RTE (blue).
Toluidine blue helps us see more clearly the inside of WBC from the inside of Renal tubular epithelial cells.
Urine specimens that contain a large amount of mononuclear cells (except for epithelial cells) may need to be referred to cytology. —-> Difficulty may arise when differentiating WBC’s from mononuclear cells (including RTE’s). RTE’s are larger than WBC, but not as round, and the nucleus is usually prominent.
State the purpose of Sudan III and oil red O
Lipid stain
-Used to stain triglycerides and neutral fat.
-Used to identify fat except for cholesterol (reddish color)
It differentiates lipids like Oval fat bodies. In an unstained urine oval fat body will like like clear small cells all clumped up together. When we apply the stain it will stain red and that will help us confirm lipids.
True or False triglycerides and neutral fats stain orange-red and cholesterol stains yellow.
False. Triglycerides and neutral fats will stain orange-red, but cholesterol will not stain.
We will need to use polarized light to help in identifying cholesterol. In polarized light, cholesterol will have those characteristics of Maltese-cross formation. It looks like for ovals and a diamond in the middle.
State the purpose of Gram in the examination of the urine sediment
In urinalysis it is used mainly to identify BACTERIAL casts (can be confused with granular casts).
Many granular casts’ appearance is very granular that it’s difficult to determine if its bacteria that is causing the appearance or if it is just things in the filtrate that got caught, that it is causing the granular appearance.
So if we are concern that there’s an infection in the tubular itself, we might want to do a Gram stain to double check.
State the purpose of Hansel stain
Used to identify eosinophils from other WBC.
-Used to identify eosinophils in urinary sediment (reddish)
–
WBC’s seen in urine are usually neutrophils associated with microbial infections (not eosinophils). —–> In allergic reactions (drug-induced, etc) producing inflammation of the renal interstitium (inflammation within the nephron), eosinophils will be present.
-It is the most common stain done in urinalysis outside that of steinheimer stain.
State the purpose of Prussian blue stains in the examination of the urine sediment
stains structures containing iron
-Used to identify hemosiderin (blue) granules
Unstained hemosiderin granules are a yellow-brown color (seen in renal tubular epithelial cells and casts after hemoglobinuria). Once they are stained the hemosiderin granules will be stained blue.
–> Side note: they actually look like tiny undefinable (not set shape or size), but differently we will see them with RTE cells.
Describe the basic principle of bright-field and their relationship to sediment examination
-routine for urinalysis
-basic principle is that objects/specimens appear dark against a light background.
–
Sediment constituents with a low refractive index will be overlooked when subjected to light of high intensity. Therefore, sediments must be examined using decreased light controlled by adjusteding the rheostat on the light source, not by lowering the condenser. Staining of the sediment also increased the visualization of these elements when using bright-field.
What is the most common type of microscopy?
bright field
Describe the basic principle of phase-contrast and their relationship to sediment examination
-enhances low refractive objects (such as hyaline casts, mucous, etc).
-the basic principle is that when light passes through cells, small phase shift occur, which are invisible to the human eye. In a phase contrast microscope, these phase shifts are converted into changes in amplitude, which can be observed as differences in image contrast.
–
A lot of hospitals use these!
Describe the basic principle of polarizing and their relationship to sediment examination
-used to identify cholesterol and crystals
Describe the basic principle of interference-contrast microscopy and their relationship to sediment examination.
-used to enhance detail (three dimension)
-basic principle is that it involves two coherent beams of light (from the same small light source) and image contest achieved with gradients in optical path. It produces clear optical sections of which transparent specimens and a 3D shadowed image.
–
not very common in hospital labs
Differentiate between normal and abnormal sediment constituents
Normal :
- 0-5 WBC/hpf
- 0-2 RBC/hpf
- less than 0-2/hpf of transitional epithelia cells
-0-2/hpf of Renal tubular epithelial cells
Abnormal:
-Eosinophils (more tha 1%)
-Bacteria
->2/hpf of RTE
Check with Caroline
Identify urine artifacts :
What is number 1?
Talcum Powder
Identify urine artifacts :
What is number 2?
Starch
Identify urine artifacts :
What is number 3?
Air
-Highly refractile
Identify urine artifacts :
What is number 4?
Oil
-Highly refractile
Identify urine artifacts :
What is number 5?
Pollen
Identify urine artifacts :
What is number 6?
clothing fiber
Identify urine artifacts:
What is number 8?
diaper fiber
Identify urine artifacts :
What is number 9?
cotton fiber
Describe and illustrate urine sediment constitutes
ask Caroline
Discuss the significance of red blood cells (RBCs) in the urinary sediment.
-Normal to have 0-2 RBC/hpf
-No nucleus
If there is RBC in the urine that means hematuria.
Note: presence of absence of RBC’s may not correlate with urine color or blood chemical result
-> 1-4 RBC/hpf but chem strip is negative
-> Chem strip is positive, but no RBC seen microscopically
—–> Typically lysed RBC, or hemoglobin or myoglobin
-Side note crenated RBC’s may be mistaken for WBC’s b/c when they shrink, they appear to have granules under the microscope –> Acetic acid will lyse RBC, but not yeast, oil droplets, nor WBCs.
What kind of disease or disorder is associated with dysmorphic rbc’s (such as ringed rbcs with blebs )
looks like a donut with Mickey Mouse ears or one ear
(Number 9 picture)
Glomerular bleeding
Discuss the significance of white blood cells (WBCs) in the urinary sediment.
-Normal value is 0-5 WBC/hpf
-Significance amount or increase amount of WBC’s in the urine is known as Pyuria.
-This usually denotes an infection or inflammation in the GU (genitourinary tract). This may be due to many causes like ….
-bacterial infection
-glomerulonephritis
-lupus erythematosus
-intersitial nephritis (Eosinophils - drug-induced/uti/parasites/renal transplant rejection)
-tumors
Name the three types of epithelial cells found in the urinary sediment
- Squamous
-Transitional
-Renal
Describe the three types of epithelial cells found in the urinary sediment
- Squamous are largest cells found in the urinary sediment. It has a prominent nucleus the size of a RBC and are easily seen under low power (10x). They may fold, may look like casts, and degenerate easily.
-Transitional Epithelial cells are smaller than Squamous. Typically have CENTRALLY located nuclei. Numerous forms and a WELL DEFINED OUTER EDGE, and a bit larger than RTE. (PEAR/AVOCADO shape)
- Renal tubule cells are smaller than squamous and most transitional, but larger than WBC. They can have a cuboidal, columnar or round shape, typically flattened edge. The NUCLEI tend to be ECCENTRICALLY located (typically off the side). May contain elements, yellow-brown granules
Give the origin of the three types of epithelial cells found in the urinary sediment
-Squamous cells’ origin are the linings of the vagina, female urethra, and lower portion of the male urethra.
-Transitional Epithelial cells originate from the lining of the renal pelvis, calyces, ureters, bladder, and upper portion of the male urethra.
-The Renal tubule cells originate from the proximal, distal, and collecting duct.
Give the significance of the three types of epithelial cells found in the urinary sediment
- Squamous cells have no pathological significance as they represent normal cellular sloughing.
-For Transitional epithelial cells, normal amounts are <0-2/HPF. Incr amounts may be seen in invasive urologic procedures like catherization, but THIS IS NOT PATHOLOGIC in this case. Anything weird like abnormal morphology (vacuoles or irregular nuclei ) we send it to cytology.
-For Renal tubule cells, normal amounts are 0-2/hpf. Greater than 2 hpf, tells us there is damage or necrosis (death of body tissue) to renal tubules. Ex: infection, drug toxicity, heavy metals, allergic reactions.
What are clue cells?
Squamous Epithelial Cells with bacteria.
Clue cells are pathogologic when present in large numbers. HOWEVER they are NOT reported in Urine at most hospitals.
–
-These cells are indicative of bacterial vaginosis (when in large quantity).
-Squamous epithelial cells covered with bacteria (Gardnerella vaginialis). The cells will appear granular and irregular, due to the bacteria covering the cell.
Discuss the significance of oval fat bodies
-Oval fat bodies are Renal tubular epithelial cells that have absorbed lipids from the glomerular filtrate. They are highly pathological, very rare. They are associated with lipiduria (fat in urine), which is associated with
-NEphrotic syndrome: damage to glomerulus
-Tubular necrosis (damage to tubules)
-Diabetes melitus (blood sugar is too high)
-Trauma (bone marrow fat release in urine)
-overall lipid storage diseases
–
-The lipid material appears highly refractile
-They are typically seen along with free fat droplets or fatty casts.
Compare and contrast the three types of lipid found in urine and how to identify each type
-Triglycerides and neutral fats stain orange-red with Oil Red O and Sudan III.
-Cholesterol will not stain with Oil Red O and Sudan III, so we need to use a polarize light next to help identify. It will have a Maltese cross formation —> oval fat bodies
-Fya, for all fats we do oil red O and Sudan III.
Explain the process of cast formation and their sequence of degradation
- Tamm-Horsfall (Uromodulin) protein aggregates to RTE cells to form protein fibrils (small or slender fiber).
- Fibrils form a loose network (components in urine can get trapped
- Further interweaving of fibrils form solid structure: Matrix
- Urine components attach to matrix
- Cast detaches from RTE, exits nephron
Granular cast pick up material from urine, material stat to degrade forming “granularity” such as
-crystals
-RBC
-WBC
-Cellular material from RTE
- Destruction of the cells may occur from free cells in the tubular lumen and then incorporated when the cast is formed or the cells may undergo destruction when the cast is already formed as a cellular cast.
–
-Casts formed only in the nephron of the kidney, specifically in the loop of Henle, Distal tubule, and collecting duct.
What does Cylinduria mean?
Casts in Urine
–
-Cast formation occurs more readily if:
–>Urine flow is decreased (urinary stasis)
–>pH is acidic (casts can dissolve in alkaline pH)
–>Electrolytes are increased
-Causes of cast formation can be pathological and non-pathological:
–>due to exercise or dehydration
–>renal conditions
True or False: Formation of casts can block urine flow within nephron
True
