ENHANCING URINE SEDIMENT VISUALIZATION Flashcards
(37 cards)
The standardized quantitative microscopic examination of
urine sediment made its clinical laboratory debut in______.
At that time,_____ developed a procedure to quantify
formed elements in a _______ specimen collection.
The purpose of this test, the Addis count, was to follow the progress of renal diseases , particularly______.
Increased numbers of red blood cells (RBCs), white blood cells
(WBCs), or casts in the urine indicated disease progression.
1926
Thomas Addis
12-hour overnight urine
acute glomerulonephritis
ADDIS COUNT
A disease process was indicated when one or more of the following
cell changes occurred:
The number of RBCs exceeded____;
the number of WBCs exceeded____; or the number of casts exceeded___.
Because the Addis count was time-consuming and chemical methods are currently available to monitor the progression of renal disease, it is no longer routinely performed
despite its ability to accurately detect changes in the excretion of
urinary formed elements.
500,000
2 million
5000
Factors That Require
Standardization in the Microscopic
Examination
• Urine volume used (e.g.,______)
• Speed of centrifugation (_____)
• Time of centrifugation (______)
• Concentration of sediment prepared (e.g.,_______)
• Volume of sediment examined—determined by commercial slides used and microscope optical properties (i.e., ocular field number)
• Result reporting—format, terminology, reference intervals,
magnification used for assessment
10 mL, 12 mL, 15 mL
400 or 450 × g
5 minutes
10:1, 12:1, 15:1, 30:1
The concentrated sediment can
be prepared using a variety of initial urine volumes.
Frequently, the initial volume of urine is_____ with a _____ concentration of sediment prepared for microscopic viewing.
However, initial urine volumes ranging from______ can be used.
12 mL with a 12 to 1 (12:1) concentration
3 to 15 mL
_______ and ______are not recommended because they do not yield standardized, reproducible
results.
If glass slides are used, the laboratorian should always
pipette an exact amount (e.g.,____) of the resuspended sediment onto the glass slide using a calibrated pipette.
The volume of sediment dispensed is determined by each laboratory and depends on the size of the coverslip used.
The urine sediment volume must fill the entire area beneath the coverslip without
excess.
Bubbles and uneven distribution of the sediment components can result when the coverslip is applied (e.g., heavier components such as_____ are pushed or concentrate near the coverslip edges).
Glass microscope slides and coverslips
15 μL
casts
When using brightfield microscopy, it can be difficult to see urine sediment components (e.g.,2) that have a similar refractive index to that of urine.
Because their
refractive indexes are similar, there is insufficient contrast to
enable optimal viewing.
mucus
hyaline casts
changes the refractive index
of formed elements and increases their visibility.
Staining
3 are difficult to see under brightfield microscopy; the use of stains or phase microscopy enhances their visualization.
Hyaline casts
mucus threads
bacteria
crystals, which can resemble RBCs
monohydrate calcium oxalate
The most commonly used stain is a supravital stain consisting of
(2) , also known as the_____
crystal-violet and safranin
Sternheimer-Malbin stain
This stain enhances formed element identification by enabling more detailed viewing of internal
structures, particularly of (3)
Other formed elements (e.g., RBCs, mucus) stain characteristically, and their descriptions are noted on the package inserts provided with commercially prepared stains.
Sternheimer Malbin
WBCs, epithelial cells, and casts.
One disadvantage of its use is that in strongly alkaline urines, this stain can precipitate, which obstructs the visualization of sediment components.
Sternheimer Malbin
The stain is a metachromatic dye that stains various cell components differently; hence, the differentiation between the nucleus and the cytoplasm becomes more apparent.
0.5% Toluidine blue
The _______stain enhances the specific identification of cells and aids in distinguishing cells of similar size, such as leukocytes from
renal collecting duct cells
toluidine blue
Although ______is not actually a stain, it can be helpful
in identifying WBCs.
acetic acid
WBCs can appear small, especially
in hypertonic urine, with their nuclei and granulation not readily apparent.
By adding 1 to 2 drops of a_______ to a few drops of urine sediment, the nuclear pattern of WBCs and epithelial cells is accentuated, whereas RBCs are lysed.
2% solution of acetic acid
is often used to confirm the presence of neutral fat or triglyceride suspected during the microscopic examination
Sudan III or oil red O
Sudan III or oil red O
These lipids stain ____ or ____and may be found
(1) free floating as droplets or globules;
(2) within renal cells or macrophages, aptly termed oval fat bodies; or
(3) within the matrix of casts as droplets or oval fat bodies.
An important note is that only_______ are stained.
orange or red
neutral fats (e.g., triglycerides)
cholesterol and cholesterol esters do not stain and must be confirmed by…
polarizing microscopy.
provides a means of positively identifying bacteria in the urine and differentiating them as Gram negative or Gram positive
Gram stain
To perform a Gram stain, a dry preparation of the urine sediment is made on a microscope slide by smearing and air drying or by cytocentrifugation. As in the microbiology laboratory, the slide is heat fixed and then stained.
Gram-negative bacteria appear____, whereas Gram-positive
bacteria appear____.
pink
dark purple
To facilitate the visualization of hemosiderin, free floating or
in epithelial cells and casts, the_________ aka _______, is used.
Prussian blue reaction, also
known as the Rous test
Hansel stain (2)
methylene blue
eosin-Y in methanol
is used in the urinalysis laboratory specifically to identify
eosinophils in the urine
Hansel stain (methylene blue and eosin-Y in methanol)
