Microscopic Examination of Urine (F) Flashcards
1
Q
What are the purposes of microscopic examination of urine?
A
To detect and identify insoluble mats present in the urine
2
Q
What are the diff sources of formed elements to the urine?
A
1) Blood
2) Kidney
3) Lower GUT
4) External contamination
3
Q
What are the formed element constituents of urine?
A
1) RBCs
2) WBCs
3) Epithelial cells
4) Casts
5) Crystals and artifacts
6) Bacteria, yeast, parasites
7) Mucus, sperm
4
Q
Sxs should be examined while what?
A
While fresh or adequately preserved
5
Q
What are the formed elements that disintegrate rapidly particularly in dilute alkaline urine?
A
1) RBCs
2) WBCs
3) Hyaline casts
6
Q
What are the effects brought by refrigeration?
A
It may cause precipitation of amorphous urates and phosphates and other non-pathologic crystals that can obscure other elements in the urine sediment
7
Q
If the (refrigerated?) sx is warmed to 37 DC prior to centrifuging, what happens?
A
Some crystals may dissolve
8
Q
Dilute random sxs may cause what?
A
These sxs may cause false (-) readings
9
Q
What should be done to a sx before decanting a portion of it into a centrifuge tube?
A
Thoroughly mix the sx
10
Q
What is the std amt of sx volume and what is done to this sx volume?
A
10 - 15 mL is centrifuged in a conical tube
11
Q
What is the ideal volume for rgnt strip testing?
A
12 mL
12
Q
What is the purpose of centrifugation?
A
To produce an optimum amt of sediment w/ the least chance of damaging the elements
13
Q
What is the RCF for centrifugation (of urine?)?
A
400 RCF
14
Q
What is the speed for centrifugation (of urine?)?
A
1,500 - 2,000 rpm
15
Q
What is the time duration of centrifugation (of urine?)?
A
3 - 5 mins
16
Q
What is the purpose of tachometer?
A
Instrument that measures the speed in rpm
17
Q
What should remain in the tube after decantation?
A
A uniform amt of urine and sediment should remain
18
Q
What are the volumes of urine and sediment that should remain the tube after decantation?
A
0.5 and 1.0 mL respectively
19
Q
How is concentration factor obtained?
A
It is the volume of urine centrifuged divided by the sediment volume
20
Q
What should be done to maintain a uniform sediment concentration factor?
A
Urine should be aspirated off rather than poured off
21
Q
What must be done to the sediment?
A
It must be thoroughly resuspended by gentle agitation
22
Q
What is the recommended volume of sediment to be examined?
A
20 uL (0.02 mL)
23
Q
What should be done to 20 uL of sediment for examination?
A
It should be covered by a 22 X 22 mm glass cover slip
24
Q
Allowing the sx to flow outside the cover slip may result in what?
A
It may result in the loss of heavier elements such as casts
25
How should microscopic examination be performed (in terms of # of fields)?
Microscopic examination should be performed by observation of a min of 10 fields under both low (10x) and high (40x) power
26
What is the purpose of LPO (in terms of examination of sediment)?
The slide is first examined under low power to detect casts and to ascertain the general composition of the sediment
27
What is the purpose of HPO (in terms of examination of sediment)?
To identify elements such as casts
28
Casts have the tendency to what?
To locate near the edges of the cover slip
29
Due to the tendency done by casts, what is recommended to be done?
Low power scanning the cover slip parameter is recommended
30
If the urine sediment is examined under reduced light, what is the result?
Many sediment constituents have a refractive index similar to urine
31
How are casts reported (via microscopic examination)?
They are reported as the ave # per lpf following examination of 10 fields
32
How are RBCs and WBCs reported (via microscopic examination)?
They are reported as # per 10 hpfs
33
How are epithelial cells, crystals, and other elements of urine frequently reported (via microscopic examination)?
They are reported in semiquantitative terms such as rare, few, moderate, and many, or as 1+, 2+, 3+, and 4+
34
What is the significance of the given screening test?
Screening test: Color
Blood
35
What is the significance of the given screening test?
Screening test: Clarity
Hematuria vs Hemoglobinuria or myoglobinuria
Confirm pathologic or non-pathologic cause of turbidity
36
What is the significance of the given screening test?
Screening test: Blood
RBCs
37
What is the significance of the given screening test?
Screening test: Protein
Casts and cells
38
What is the significance of the given screening test?
Screening test: Nitrite
Bacteria and WBCs
39
What is the significance of the given screening test?
Screening test: LE
WBCs, WBC casts, and bacteria
40
What is the significance of the given screening test?
Screening test: Glucose
Yeast
41
What is Addis count?
It is the 1st procedure to standardize the quantitation of formed elements in the urine microscopic analysis
42
When is Addis count discovered(?)?
1926
43
What is used in Addis count (including its functions)?
Hemocytometer is used to ct the # of RBCs, WBCs, casts, and epithelial cells present in a 12 hr sx
44
What is the range of normal value for RBCs in Addis ct?
0 - 500,000 RBCs
45
What is the range of normal value for hyaline casts in Addis ct?
0 - 5,000 hyaline casts
46
What is the range of normal value for WBCs and epithelial cells in Addis ct?
0 - 1,800,000 WBCs and epithelial cells
47
What are the purposes of stains (for urine sediments)?
1) It increases the overall visibility of sediment elements being examined
2) It also imparts identifying characteristics to cellular structures
(such as the nuclei, cytoplasm, and inclusions)
48
What is principle of microscopy (including its action) is used for microscopic examination of stained urine sediments?
Bright-field microscopy by changing the refractive index of urine sediments
49
What is the most frequently used stain?
Sternheimer-Malbin stain
50
What are the components of Sternheimer-Malbin stain?
1) CV
| 2) Safranin O
51
What are the actions of Sternheimer-Malbin stain?
1) Delineates structure
| 2) Contrasting colors of the nucleus and cytoplasm
52
What are the functions of Sternheimer-Malbin stain?
Identifies:
1) WBCs
2) Epithelial cells
3) Casts
53
What is the characteristic of 0.5% toluidine blue?
It is a metachromatic stain
54
What is the action of 0.5% toluidine blue?
Provides enhancement of nuclear detail
55
What is the function of 0.5% toluidine blue?
Differentiates WBCs and renal tubular epithelial (RTE) cells
56
What is the purpose of 0.5% toluidine blue?
It is used in the examination of cells from other body fluids
57
What is the purpose of 2% acetic acid?
To enhance nuclear details
58
What are the actions of 2% acetic acid?
1) Lyses RBCs
| 2) Enhances nuclei of WBCs
59
What is the function of 2% acetic acid?
Distinguishes RBCs from WBCs, yeast, oil droplets, and crystals
60
What are the exs of lipid stains?
1) Oil Red O
| 2) Sudan III stains
61
What is the function of lipid stains?
Identify free fat droplets and lipid-containing cells and casts
62
What is the action by lipid stains?
Stain trigly and neutral fats orange-red
Do not stain chole
63
What are the purposes of gram stain?
1) Differentiates gram (+) and gram (-) bacteria
| 2) Identifies bacterial casts
64
What is the action of Hansel stain?
Methylene blue and eosin Y stains eosinophilic granules red (others are blue)
65
What is the function of Hansel stain?
Identifies urinary eosinophils
66
What is the term called if a pt has eosinophils present in his or her urine?
Eosinophiluria
67
What is the action of prussian blue stain?
Stains structures containing iron
68
What is the function of prussian blue stain?
Identifies yellow-brown granules of hemosiderin in cells and casts
69
What are the diff types of microscopy?
1) Bright-field microscopy
2) Phase-contrast microscopy
3) Dark-field microscopy
4) Polarizing microscopy
5) Fluorescence microscopy
6) Interference-contrast microscopy
70
What is the purpose of bright-field microscopy?
It is used for routine microscopic examinations
71
What is the function of phase-contrast microscopy?
To enhance the visualization of elements w/ low refractive indices (such as hyaline casts, mixed cellular casts, mucous threads, and Trichomonas)
72
What are the purposes of dark-field microscopy?
1) It is used for unstained sxs
| 2) It aids in the identification of Treponema pallidum
73
What is the purpose of polarizing microscopy?
It aids in the identification of chole in oval fat bodies, fatty casts, fat droplets, and crystals
74
Lipids and crystals have the ability to what?
To rotate the path of the unidirectional polarized light beam to produce characteristic colors in crystals and Maltese cross formation in lipids
75
What is birefringent?
Refract light in 2 dimensions at 90 deg to each other
76
What are the 2 types of birefringence?
1) Positive birefringence
| 2) Negative birefringence
77
What is (+) birefringence?
Substance that rotates the plane of polarized light 90 deg in a clockwise direction
78
What is (-) birefringence?
Substance that rotates the plane in a counterclockwise direction
79
What is the purpose of fluorescence microscopy?
It allows the visualization of naturally fluorescent microorganisms or those stained by a fluorescent dye including labeled Ags and Abs
80
What is the function of interference-contrast microscopy?
It produces a three-dimensional microscopy image and layer by layer imaging of a sx
81
What are the characteristics of RBCs (as urine sediment)?
1) Non-nucleated biconcave disks
2) Crenated in hypertonic urine (hypersthenuric)
3) Ghost cells in hypotonic urine or diluted urine (hyposthenuric)
4) Dysmorphic RBC (vary in size, have cellular protrusions, or are fragmented) seen in glomerular membrane damage
82
What are the sources of identification error for RBCs (as urine sediment)?
1) Yeast cells
2) Oil droplets
3) Air bubbles
83
What is the manner of reporting RBCs (as urine sediment)?
Average # per 10 hpfs
84
At what tests can RBCs (as urine sediment) be correlated?
Color and rgnt strip blood rxn
85
What are the clinical significance of RBCs (as urine sediment)?
1) Associated w/ damage to the glomerular membrane
2) Vascular injury within genitourinary tract
3) Microscopic hematuria: glomerular disorders and malignancy of the urinary tract and the presence of renal calculi
86
What are the types of RBCs (as urine sediment)?
1) Eumorphic RBC
| 2) Dysmorphic RBC
87
What are the characteristics of WBCs (as urine sediment)?
1) Larger than RBCs
2) Granulated, multilobed neutrophils
3) Glitter cells in hypotonic urine
4) Mononuclear cells w/ abundant cytoplasm
88
What is the source of identification error for WBCs (as urine sediment)?
RTE cells
89
What is the manner of reporting WBCs (as urine sediment)?
Ave # per 10 hpfs
90
At what tests can WBCs (as urine sediment) be correlated?
1) LE
2) Nitrite
3) SG
4) pH
91
What are the characteristics of neutrophils?
1) They lyse rapidly in dilute alkaline urine and begin to lose nuclear detail
2) If exposed to hypotonic urine, it absorbs H2O and swell
3) They are stained light blue w/ Sternheimer-Malbin stain
92
What is the characteristic of glitter cells?
These are cells that produce a sparkling appearance due to the Brownian movement of the granules within the cells
93
What are the clinical significance of WBCs (as urine sediment)?
1) Pyuria
2) Indicates inflammation or infection of the GUT
3) Bacterial infections: pyelonephritis, cystitis, prostatitis, and urethritis
4) Urinary calculi
5) Tumors and neoplasia
6) Glomerulonephritis, lupus erythematosus, and interstitial nephritis
7) Contamination of vaginal and prostate secretions
94
What is pyuria?
It is the presence of of increased #s of WBCs in the urine sediment (normal: < 5 WBCs/hpf)
95
What are the characteristics of urinary eosinophils?
1) They are primarily associated w/ drug-induced interstitial nephritis
2) Small #s may be seen w/ UTI and renal transplant rejection
3) Urine sediment may be concentrated by routine centrifugation alone or w/ cytocentrifugation
4) Not normally seen in the urine
96
What is the preferred stain for eosinophils (as urine sediment)?
Hansel's stain, but Wright's stain can also be used
97
Are eosinophils normally seen in the urine (as urine sediment)?
No, hence, the finding of > 1% eosinophils is considered significant
98
When are mononuclear cells seen in urine?
They are seen in increased #s in the early stages of renal transplant rejection
99
True or False
Lymphocytes, monocytes, macrophages, and histiocytes may be present in large #s and are usually not identified in the wet preparation urine microscopic analysis
False, because lymphocytes, monocytes, macrophages, and histiocytes may be present in small #s
100
True or False
Monocytes, macrophages, and histiocytes are small cells and may appear vacuolated or contain inclusions
False, because monocytes, macrophages, and histiocytes are large cells
101
What is cytodiagnostic urine testing?
It is the test done if sxs containing an increased amt of mononuclear cells cannot be identified as epithelial cells
102
What are the characteristics of squamous cells (as urine sediment)?
1) They are the largest cells found in the urine sediment
2) They contain abundant, irregular cytoplasm, and a prominent nucleus
3) Usually at least a few squamous epithelial cells are present in the urine sediment
4) They can serve as a good reference for focusing of the microscope
5) Squamous epithelial cells are commonly reported in terms of rare, few, moderate, or many, in terms of low power
103
What are the characteristics of clue cells?
1) A variation of the squamous epithelial cell w/ pathologic significance
2) They appear as squamous epithelial cells covered w/ the gram variable bacteria (Gardnerella coccobacillus) throughout the surface and extend beyond the edges of the cell
104
Clue cells are indicative of what?
They are indicative of vaginal infection
105
What are the causative agents of vaginal infection?
1) Gardnerella vaginalis
| 2) Mobiluncus spp
106
What is the clinical significance of clue cells?
Bacterial vaginosis (non specific vaginitis)
107
What are the characteristics of transitional epithelial (urothelial) cells?
1) They are smaller than squamous cells
| 2) They appear in several forms including spherical, polyhedral, and caudate
108
Where do transitional epithelial (urothelial) cells originate from?
They originate from the lining of the:
1) Renal pelvis
2) Calyces
3) Ureters
4) Bladder
They also originate from the upper portion of the male urethra
109
What is normal cellular sloughing?
This is where transitional epithelial (urothelial) cells are present in small #s in normal urine
110
The differences in transitional epithelial (urothelial) cells are caused by what?
The differences are caused by the ability of transitional epithelial cells to absorb large amts of H2O
111
What are the clinical significance of transitional epithelial (urothelial) cells?
1) Invasive urologic procedures
| 2) Malignancy or viral infection
112
What are the characteristics of invasive urologic procedures?
1) Present in catheterization
| 2) They are not clinically significant
113
What occurs in invasive urologic procedures (caused by transitional epithelial cells)?
Increased #s of transitional cells seen singly, in pairs, or in clumps (syncytia) are present
114
What occurs in malignancy or viral infection (caused by transitional epithelial cells)?
Increase in transitional cells exhibiting abnormal morphology such as vacuoles and irregular nuclei
115
What are the differences bet RTE cells and transitional cells (in terms of nucleus and shape)?
In terms of nucleus:
1) RTE cells: eccentric
2) Transitional cells: centrally
In terms of shape:
1) RTE cells: round, oval, or cuboidal
2) Transitional cells: spherical, polyhedral, and caudate
116
What are the characteristics of RTE cells?
1) Columnar, rectangular, round, oval, or cuboidal
2) Has an eccentric nucleus
3) Possibly bilirubin stained or hemosiderin-laden (yellow-brown hemosiderin granules)
4) The cytoplasm is coarsely granular and often resemble casts
117
What is the characteristic of cells from PCT in comparison to other RTE cells?
The cells from PCT are larger than other RTE cells
118
What is the characteristic of cells from DCT?
Cells from DCT are smaller and are round or oval
119
What is the characteristic of collecting duct RTE cells?
They are cuboidal and are never round
120
What are epithelial fragments?
These are cells from the collecting duct that are present in grps of 3 or more
121
When are epithelial fragments present?
These are present in severe tubular injury
122
What is the function of prussian blue stain?
It is used to confirm the presence of iron-containing hemosiderin granules
123
What are the characteristics of oval fat bodies?
1) They are highly refractile lipid-containing RTE cells
| 2) Their nucleus is difficult to observe
124
What are the stains used to confirm the presence of oval fat bodies?
1) Sudan III
2) Oil Red O
* these are both fat stains
125
What is the principle of microscopy that can be used to confirm the presence of oval fat bodies?
Polarized microscopy
126
What is the manner of reporting of oval fat bodies?
Ave # per hpf
127
Where can oval fat bodies be correlated?
1) Fat droplets
| 2) Fatty casts
128
What are the clinical significance of oval fat bodies?
1) Lipiduria
2) Severe tubular necrosis
3) DM
4) Present in trauma
5) Present in lipid-storage diseases
6) Indicative of necrosis of the renal tubules
129
What is lipiduria?
It is most frequently associated w/ damage to the glomerulus caused by nephrotic syndrome
130
What happens if an individual experienced trauma (in correlation to oval fat bodies)?
In trauma cases, it cause release of bone marrow fat from the long bones
131
What may also be present in lipid-storage diseases?
Large fat-laden histiocytes
132
What are bubble cells (in correlation to oval fat bodies)?
These are RTE cells containing large, nonlipid-filled vacuoles, that represent injured cells in w/c the endoplasmic reticulum has dilated prior to cell death
133
What are the conditions producing tubular necrosis (in correlation to oval fat bodies)?
1) Exposure to heavy metals
2) Drug-induced toxicity
3) Hgb and myoglobin toxicity
4) Viral infections (hepa B)
5) Pyelonephritis
6) Allergic rxns
7) Malignant infiltrations
8) Salicylate poisoning
9) Acute allogenic transplant rejection
134
What are the clinical significance of RTE cells?
1) RTE cells may also be seen as secondary effects of glomerular disorders
135
What is the normal value of RTE cells?
0 - 2 RTE cells per hpf
136
What is the purpose of renal fragments?
They serve as an indication of severe tubular injury w/ basement membrane disruption
137
When are single cuboidal cells seen?
These are seen in cases of salicylate poisoning
138
RTE cells absorb what?
RTE cells absorb bili present in the filtrate as the result of liver damage
RTE cells also absorb hgb present in the filtrate and are converted to hemosiderin
139
What are the diff miscellaneous structures present in urine?
1) Bacteria
2) Yeast
3) Trichomonas
4) Spermatozoa
5) Mucus
140
What are the special structures present in urine that are clinically significant?
1) Urinary casts
| 2) Urinary crystals
141
Bacteria present in the urine are usually present as what?
Bacteria are usually present as contaminants
142
What are the sxs where bacteria are usually present as contaminants?
1) Vaginal contamination
2) Urethral contamination
3) External genitalia contamination
4) Contamination present in the collection container
143
What happens to the bacteria (w/c are usually present as contaminants) present in the urine if the sx remains at room temp for extended periods?
These contaminant bacteria multiply rapidly in sxs that remain at room temp for extended periods
144
What are the characteristics of bacteria that are usually present as contaminants?
1) Has no clinical significance
2) They may produce a (+) nitrite test result
3) They are present in urine sx having a pH of above 8
4) They appear as small spherical and rod-shaped structures
5) They are motile
145
If the urine sx has a pH above 8, it indicates what?
It is an unacceptable sx
146
What are the sources of errors (in correlation to bacteria that are usually present as contaminants)?
1) Amorphous phosphates
| 2) Amorphous urates
147
What is the manner of reporting for bacteria (that are usually present as contaminants)?
Few, moderate, or many per hpf, the presence of WBCs may be required
148
At what tests can presence of bacteria be correlated?
1) pH
2) Nitrite
3) LE
4) WBCs
149
What is the clinical significance of bacteria being present in the urine?
The presence of bacteria w/ increased WBC can be indicative of either lower or upper UTI
150
If bacteria in the urine is present, it is routinely followed up w/ what?
It is routinely followed up w/ a sx for quantitative urine culture
151
What bacteria are the most frequently associated w/ UTI?
Enterobacteriaceae
152
What is the concentration or amt of bacteria present in the urine that is considered as significant?
> 100,000 cfu/mL
This is considered as significant bacterial colony ct
153
What are the characteristics (in terms of appearance) of yeast and hyphae?
1) Small
2) Oval
3) Refractile structures w/ buds and/or w/ hyphae
154
Yeast and hyphae appear as what in cases of severe infections?
They may appear as branched, mycelial forms
155
What is the source of error for yeast and hyphae?
RBCs
156
What is the manner of reporting of yeast and hyphae?
Rare, few, moderate, or many per hpf, the presence of WBCs may be required
157
At what tests can yeast and hyphae are correlated?
1) Glucose
2) LE
3) WBCs
158
Candida albicans are primarily seen in the urine of what?
These are primarily seen in the urine of:
1) Diabetic pts
2) Immunocompromised pts
3) Women w/ vaginal moniliasis
159
What is the sx that provides an ideal medium for the growth of yeast?
The acidic, glucose-containing urine of diabetic pts
160
Contaminants (in correlation w/ yeast and hyphae) are indicated w/ what?
Indicated w/ the absence of WBC and prolonged storage
161
What are the differences bet RBC and yeast?
In terms of size:
1) RBCs are slightly larger than yeast cells
2) Yeast cells are slightly smaller than RBCs
In terms of shape:
1) RBCs are more uniform in shape than yeast cells
2) Yeast cells may be more oval than circular in shape
162
True or False
Yeast cells also may have a single bud
True
163
What are the characteristics of RBCs in fresh sxs?
RBCs are:
1) Round
2) Biconcave
Also, a dimple may be observed in the middle of the cell
164
After 5 - 10 mins, what will happen to RBCs?
RBCs will crenate and get a jagged appearance
165
What are the characteristics (in terms of appearance) of spermatozoa?
Has tapered oval head with long, thin tail
166
What is the source of error for spermatozoa?
None
167
What is the manner of reporting for spermatozoa?
Present
* Based on lab protocol
168
At what test can spermatozoa be correlated?
Protein
169
What is mucus?
It is a protein mat
170
Mucus is produced by what?
It is produced by the:
1) Glands and epithelial cells of the lower GUT
2) RTE cells
171
What is uromodulin?
It is a major glycoprotein constituent of mucus excreted by the RTE cells
172
What is the characteristic (in terms of appearance) of mucus?
It appears as single or clumped threads w/ a low refractive index
173
What is the source of error for mucus?
Hyaline casts
174
What is the manner of reporting of mucus?
Rare, few, moderate, or many per lpf
175
At what test can mucus be correlated?
None
176
What are the parasites that can be present in the urine?
1) Trichomonas vaginalis
2) Schistosoma haematobium (ova)
3) Enterobius vermicularis (ova)
177
What is the most frequently encountered parasite in the urine?
Trichomonas vaginalis
178
What are the characteristics of Trichomonas vaginalis?
1) Trophozoite that is a pear-shaped flagellate w/ an undulating membrane
2) It can be easily identified in wet preparations by its rapid darting movement
3) When not moving, it is more difficult to be identified
179
What is the manner of reporting for Trichomonas vaginalis?
Rare, few, moderate, or many per hpf
180
What is the primary symptom caused by Trichomonas vaginalis?
Vaginal inflammation
181
How is Trichomonas vaginalis transmitted?
It is a sexually transmitted pathogen
182
Male pts caused by Trichomonas vaginalis are symptomatic or asymptomatic carriers?
Male pts are often asymptomatic carriers
183
What are the characteristics of Schistosoma haematobium (ova)?
1) It is a blood fluke egg w/ terminal spine
2) 50 X 150 um in diameter
3) Leukocytes (eosinophils) and RBCs are usually present (when this parasite is seen?)
184
Schistosoma haematobium (ova) is associated w/ what?
W/ Urogenital schistosomiasis
185
What is the characteristic of Enterobius vermicularis (ova)?
D-shaped ova
186
Enterobius vermicularis is a form of what contaminant?
It is a form of fecal contaminant
187
Dx of Enterobius vermicularis (ova) from the urine can be correlated w/ what?
Stool analysis
188
What is the term called if a pt has presence of urine casts in his or her urine sx?
Cylinduria
189
True or False
Casts are the only urinary sediment that are unique to the kidney
True
190
How are urine casts formed?
They are formed within the lumens of the distal convoluted tubules and collecting ducts
191
Microscopic view of urine casts provides what?
It provides a microscopic view of the conditions w/ the nephron
192
The shape of urine casts is representative of what?
Representative of the tubular lumen, w/ parallel sides and somewhat rounded ends
193
Urine casts may contain what?
Contain additional elements present in the filtrate
194
What is the other term for uromodulin?
Tamm-Horsfall protein
195
What is the major constituent of urine casts?
Uromodulin
196
The protein gels more readily under conditions of what?
Under conditions of urine flow stasis, acidity, and the presence of Na and Ca
197
What are the factors that promote urinary cast formation?
1) Increased proteins (Bence-Jones protein, albumin, myoglobin, and hgb)
2) Urinary stasis
3) Acid pH
4) High solute concentration
5) Cellular debris
6) Low glomerular filtration rate
198
What are the functions of urinary casts?
1) Inhibits Ca crystallization in renal fluids
| 2) Provide defense against infection
199
What is the process (or steps) of cast formation?
1) Initiation
2) Growth
3) Maturation
4) Evacuation
200
What are the occurrences present in initiation (step)?
1) Tamm-Horsfall protein are fixed to the distal tubular walls forming a porous sponge-like lattice
2) Early hyaline casts are formed
201
What are the occurrences present in growth (step)?
1) As time goes, more elementary fibrils and proteins are added to the initial structure, making the pore smaller
2) Urine flow is reduced through the structure
202
What are the occurrences present in maturation (step)?
1) After complete obstruction of urine flow, the cast matrix is modified by the tubular act
2) Proteins and other elements from the surrounding are added
3) W/ time, the epithelial cells and other elements degenerate forming a coarsely granular, then finely granular casts
4) Waxy casts are the final step in the formation of casts and usually indicate chronic tubular disease
203
What are the occurrences present in evacuation (step)?
1) The surrounding cells act and the hydrostatic pressure make the cast lose its adherence to the tubular wall
2) Casts are evacuated by urinary flow and hydrostatic pressure
204
What is the magnification used for examination or detection of urinary casts (microscopic examination)?
Low power magnification
205
Urinary casts has low refractive index, hence, what should be done?
Observation under subdued light
206
What magnification is used for further identifying urinary casts as to composition (microscopic examination)?
High power magnification
207
The cast matrix dissolves quickly in what urine?
In dilute, alkaline urine
208
What is the manner of reporting for urinary casts?
Ave # per LPO
209
What is the most frequently seen cast?
Hyaline cast
210
What are the characteristics of hyaline cast?
1) Consists almost entirely of uromodulin
| 2) Appear colorless in unstained sediments and have a refractive index similar to that of urine
211
What is the morphology of hyaline cast?
1) Has normal parallel sides
2) Has rounded ends
3) Cylindroid forms, and wrinkled or convoluted shaped
212
What is the normal range for hyaline cast?
0 - 2/lpf
213
What are the clinical significance of hyaline cast?
These are increased in:
1) Acute glomerulonephritis
2) Pyelonephritis
3) Chronic renal disease
4) Congestive heart failure
5) Strenuous exercise
214
What is the second most common type of cast?
Granular cast
215
What are the characteristics of granular cast?
1) It is generally the result of degeneration of cells in cellular casts
2) It can result either from the breakdown of cellular casts, or the inclusion of aggregates of plasma proteins (e.g. albumin) or Ig light chains
216
What is the characteristic (in terms of appearance) of granular cast?
Has fine, large, and coarse granules
217
What are the clinical significance of granular cast?
1) Renal stasis
2) Chronic renal disease
3) Can be present for a short time after strenuous exercise (like hyaline casts)
218
What are the characteristics of granular cast seen in pts w/ acute tubular necrosis?
Muddy brown granular cast
219
What does granular, dirty, brown casts represent?
These represents hgb degradation products such as methemoglobin
220
What are the characteristics of waxy cast?
1) Has very high refractive index
2) Yellow, gray, or colorless
3) Brittle
221
What is the morphology of waxy cast?
1) Has smooth homogenous appearance
2) These are short, broad w/ blunt or broken ends
3) Has cracked or serrated edges
4) Has jagged ends w/ notches
222
What are the clinical significance of waxy cast?
1) Extreme urine stasis
2) Severe chronic renal failure
3) Malignant hypertension
4) Diabetic nephropathy
223
What are the sources of error for microscopic examination of waxy casts?
1) Fibers
| 2) Fecal mats
224
At what tests can dx of waxy cast be correlated?
1) Protein
2) Cellular casts
3) Granular casts
4) WBCs
5) RBCs
225
What happens in hyaline cast(?)?
Degeneration of the hyaline cast matrix and any cellular elements or granules contained in the matrix
226
What is the color of waxy casts if supravital stain (KOVA stain) is used?
Waxy casts stain a homogenous, dark pink
227
What are the characteristics of RBC cast?
1) Orange-red in color
| 2) Has a cast matrix w/c contains RBCs
228
At what tests can RBC casts be correlated?
1) RBCs
2) Blood
3) Protein
229
What are the clinical significance of RBC casts?
1) Presence of bleeding within the nephron
2) Glomerulonephritis
3) Strenuous exercise
230
What is the morphology of WBC casts?
Its cast matrix contains WBCs
231
What is the source of error for WBC cast?
WBC clumps
232
At what tests can WBC casts be correlated?
1) WBCs
2) Protein
3) LE
233
What are the clinical significance of WBC casts?
1) Pyelonephritis
| 2) Acute interstitial nephritis
234
What is the characteristic (in terms of appearance) of bacterial casts?
Bacilli bound to protein matrix
235
What is the source of error for bacterial casts?
Granular casts
236
At what tests can bacterial casts be correlated?
1) WBC casts (pyelonephritis)
2) WBCs
3) LE
4) Nitrite
5) Protein
6) Bacteria
237
What is the clinical significance of bacterial casts?
Pyelonephritis
238
What is the characteristic (in terms of appearance) of epithelial cell cast?
RTE cells attached to protein matrix
239
What is the source of error for epithelial cell cast?
WBC cast
240
At what tests can epithelial cell casts be correlated?
1) Protein
| 2) RTE cells
241
What are the clinical significance of epithelial cell cast?
1) Renal tubular damage
2) Tubular necrosis
3) Cytomegalovirus nephritis
4) Transplant rejection
242
What is the characteristic (in terms of appearance) of fatty casts?
Fat droplets and oval fat bodies attached to the protein matrix
243
What is the source of error for fatty casts?
Fecal debris
244
At what tests can fatty casts be correlated?
1) Protein
2) Free fat droplets
3) Oval fat bodies
245
What are the clinical significance of fatty casts?
1) Lipiduria
2) Nephrotic syndrome
3) Toxic tubular necrosis
4) DM
5) Crush injuries
246
If a pt has a disorder causing lipiduria, fatty casts are seen in conjunction w/ what?
In conjunction w/ oval fat bodies and free fat droplets
247
What is the characteristic of fatty casts under bright-field microscopy?
Highly refractile
248
What may be the composition of the cast matrix of fatty casts?
The cast matrix may contain few or many fat droplets, and intact oval fat bodies may be attached to the matrix
249
What is the principle of microscopy used for confirmation of presence of fatty casts?
Polarized microscopy
250
What are the stains that are used for confirmation of the presence of fatty casts?
1) Sudan III stain
| 2) Oil Red O fat stain
251
What is the characteristic (in terms of appearance) of broad casts?
They are wider than normal cast matrix
252
What are the sources of errors for broad casts?
1) Fecal mats
| 2) Fibers
253
At what tests can broad casts be correlated?
1) Protein
2) WBCs
3) RBCs
4) Granular casts
5) Waxy casts
254
What are the clinical significance of broad casts?
1) Extreme urine stasis
| 2) Renal failure
255
Where are broad casts formed?
They are formed in dilated, distended, atrophic tubules (collecting ducts)
256
What does broad casts indicate?
They indicate destruction (widening) of the tubular walls (DCT)
257
Broad casts are referred to as what?
Renal failure casts
258
What are the characteristics of broad casts?
1) They are 2 - 6 times the size of other types of casts as a result of chronic renal insufficiency
2) Highly refractile than hyaline cast
3) Denotes bad prognosis
259
What are the characteristics of waxy casts if a pt has tubular necrosis caused by viral hepatitis?
Bile-stained broad, waxy casts
260
True or False
All types of casts may occur in broad form
True
