12c. Urinalysis: Sediment Examination

Question 1

How is urine sediment examined?

Answer 1

a microscopic exam performed on a centrifuged sample
sediment exam is used to look for cells, casts, bacteria, crystals, etc
Microscopic examination complements the urine test strip
sediment exam is best method for performing a preliminary screen for the presence of bacteria
used to confirm the presence of RBC’s and WBCs
it is hugely limited by user’s technical abilities

Question 2

What is the best option for assessing the lower urogenital tract?

Answer 2

free-catch, first morning sample

Question 3

What is the best option to assess for the presence of bacteria in the bladder or kidney

Answer 3

cystosentesis

Question 4

How should samples be stored?

Answer 4

stored in frige if not evaled within 1hr
store at room temp may result in bacterial overgrowth
store in fridge may cause crystal artifacts
casts may dissolve alkaline urine

Question 5

How should a urine sample be collected for a sediment exam?

Answer 5

collect 30-10mL of urine and place it in a labelled centrifuge tube
text recommends using 10mL of urine, often only require 3-5mL from small animal patients; either volume is acceptable but be consistent

Question 6

What should we remember to set aside in the event that a urine culture is required?

Answer 6

a small “sterile” sample (0.5cc at least)

Question 7

How should a urine sample be centrifuged for urine sediment

Answer 7

make sure sample is balanced in the centrifuge
centrifuge @ 1000-2000RPM for 3-6 minutes
allow centrifuge to stop on its own
decant supernatant leaving 0.5-1.0mL of urine in the tube (pour decant into a separate container if the chemical analysis has not been performed)

Question 8

Once a sediment sample has been centrifuged, what should we do in the preparation process?

Answer 8

re-suspend sediment by flicking tube or by drawing sample up/down w/ a pipette
place 1 drop of urine on slide and add cover slip
let slide sit for 30-60 seconds
scan with the entire slide on 10x objective to look for large formed elements like casts and cluster of cells

Question 9

Once we’ve examined the slide on 10x objective, what do we do?

Answer 9

move to high dry 40x objective
ID following unstained urine (presence may be confirmed in stained urine)
WBCs, RBC, fat droplets, bacteria, crystals, transitional and epithelia cells, debris/other
look at min. 10 fields and record result
Ex. WBC 5-10/hpf OR WBC 8/hpf

Question 10

How is bacteria recorded when recording results?

Answer 10

bact may be reported as few, mod, or mny OR by # range that is present/hpf (can be reported as TNTC)
bact crystals may also be reported on 1+ to 4+ scale
Give morphological description of any bacteria that are noted (cocci, rods, single, diploid, chains, clumps)

Question 11

What do you record when bacteria is few, mod, many or TNTC in %?

Answer 11

Few: <5% of the field is occupied
Moderate: 5-25%
Many: 25-75%
TNTC: >75%

Question 12

What do you record if you see sperm and mucus?

Answer 12

Present

Question 13

What is the advantage of staining with sedi-stain?

Answer 13

highlights cells so that it is easier to identify the cell type
fat droplets do not stain

Question 14

What is the disadvantage of staining with sedi-stain?

Answer 14

often contaminated so may result in falsely elevated bacterial counts
stain sediment can be easily confused with crystals - can remove stain sediment by filtering stain weekly
quantification of elements MUST be done on the same unstained slide as the stain will dilute the sample

Question 15

How do we stain a sample?

Answer 15

NEVER add stain directly to collection tube
Add 1 drop urine + 1 drop stain to slide then cover slip OR add one drop stain to ege of coverslip after viewing the unstained urine

Question 16

In terms of sediment, what is the normal for cat/dog? What might you see instead?

Answer 16

Very little to no sediment
May have sm #’s of sperm, epithelia cells, RBCs and WBCs depending on the method of collection and neuter status
may have fat droplets, mucus threads, hyaline casts and struvite/amorphous crystals

Question 17

In terms of sediment, what might you find in an equine/rabbit. What might you find instead?

Answer 17

can have significant amount - bc of lg #s of calcium carbonate crystals in healthy animals

Question 18

What are the types of cells you might find in urine?

Answer 18

Squamous and transitional epithelial cells, renal epithelial cells, RBCs, WBCs, influenced by collection method used
Cysto +/- squamous, transitional epithelial +/-, RBC +/-, WBC X
Catheter: + squamous, ++ transitional, ++ RBC, WBC X
Free catch: + squamous, X transitional, X RBC, +/- WBC

Question 19

Why might we find RBCs in the urine? What is the presence of it called

Answer 19

Hematuria. Usually indicates hemorrhage of urogenital tract
Can be caused by inflam, infection, trauma, calculi, strenuous exercise, neoplasia, estrus, clotting/bleeding disorder, severe renal dz
Can be contam due to cystocentesis, manual expression or rough catheterization
usually corresponds with increased protein lvl on dipstick

Question 20

What do RBCs look like in the urine?

Answer 20

cells appear pale reddish brown to yellow color with a paler center
In fresh sample, uniform in size/shap (round and smooth)
often created in concentrated urine or sample that has sat for a period of time
can be confused w/ fat globules or yeast

Question 21

What do fat globules look like in urine?

Answer 21

significant variation in size, sit of diff plane, refract light, and do not take up stain

Question 22

What could WBCs in the urine indicate?

Answer 22

inflam, infection, trauma, or peripheral blood contamination - may be present in sm #’s in free catch samples due to contamination from the lower urogenital tract
>2-3/hpf is abnormal - blood contamination needs to be taken into consideration

Question 23

What do WBCs look like in urine?

Answer 23

WBC uniformly round cells, slightly lger than RBCs but smaller than renal epithelial cells
can have slight grey or greenish-yellow color
they often have granules in cytoplasm and will have lobulated nucleus (most WBC present in urine are neutrophils)
cellular features are highlighted w/ stain

Question 24

What is one way to tell if WBCs in the urine is inflammation or blood contamination?

Answer 24

There will be equal or more WBCs than RBCs, which indicates inflam

Question 25

What does increased numbers in the urine of WBCs called?

Answer 25

Pyuria (pus in the urine). WBC may be found alone or in clumps

Question 26

What could pyuria indicate?

Answer 26

A bact UTI, even if bact are not visible on sediment exam - indication to culture

Question 27

What is an acceptable amount of epithelial cells in the urine?

Answer 27

acceptable # depends on the method of collection used a marked increase in numbers usually indicates inflam

Question 28

What are the 3 diff types of epithelial cells in the urine

Answer 28

Squamous, transitional, and renal

Question 29

What value will increase on a urine test strip when epithelial cells are present?

Answer 29

protein lvl

Question 30

What do squamous epithelia cells look like in the urine?

Answer 30

located in the distal uretrha, vagina, vulva and prepuce - common in fre catch samples, seldom present if a cystocentesis is performed very lg, flat, thin, irregularly shaped easily fold over on themselves small centrally placed nuclei, abundant cytoplasm

Question 31

Wha do transitional epithelial cells look like in the urine?

Answer 31

line the bladder, ureters, renal pelvis and proximal urethra 2-4 times lger than WBC they are round to pear-shaped and have abundant granular cytoplasm have small centrally nucleus may be in clums 0-1/hpf normal, may be increased if collected by catheterization, but inc may also indicate cystitis or pyelonephritis

Question 32

What do renal epithelial cells look like in the urine?

Answer 32

smlest epithelial cells in urine only slightly larger than WBC originate from renal tubules round w/ central, large or round nucleus cytoplasm may be granular to fine granules If >1hpf are present, there is likely dz of the renal parenchymal tissue

Question 33

If we see these cells, we need to call the vet. What cells are these?

Answer 33

Neoplastic cells, any cells that contain more than one nucleoli, have multiple nuclei/cell, mitotic figures, variations in cell size, variations in the size of the nuclei, have inclusions, or appear in lg clumps May need follow up testing such as ultrasound or traumatic catheterization

Question 34

What are urine casts?

Answer 34

cylindrically shaped structures w/ parallel sides ends may be tapered, irregular or round\composed of mucoprotein may be contained trapped cells and other debrie Formed within the renal tubule

Question 35

What type of urine casts are there?

Answer 35

A. Hyaline B. Granular C. Epithelial D. Cellular (Contain RBCs, WBCs or both) E. Waxy F. Fatty G. Mixed

Question 36

How do we view urine casts?

Answer 36

Casts dissolve in alkaline urine  Urine should be examined promptly to prevent false negative results  View with 10X objective to start; move to 40X objective to determine type  0-1 hyaline or granular casts/lpf in concentrated urine may be reported in normal animals  Higher numbers indicate renal tubular injury

Question 37

What does a hyaline cast look like?

Answer 37

most common, clear, colorless and somewhat transparent, do not contain inclusions cylindrical w/ parallel sides and ROUNDED ends made of protein, easily missed bc of condenser and fine focus Easier to identify in stained than unstained samples  They do not necessarily indicate kidney disease  Low numbers (0-1/lpf) may be normal  Elevated numbers will be seen with mild renal irritation, fever, decreased renal perfusion, GA or strenuous exercise

Question 38

What do granular cast look like?

Answer 38

most common in animals they are hyaline casts that contain granules - granules are tubular epithelia cells, RBCs, WBCS that become incorporated into cast and degenerate can be classed as fine or course lg #s = severe kidney damage or acute nephritis as course granular cast ages, becomes fine granular cast

Question 39

What do epithelia casts look like?

Answer 39

A hyaline cat that has entrapped renal epithelial cells within its matrix seen w/ degenerative renal tubular dzs and acute nephritis which results in epithelia sloughing

Question 40

What do cellular - leukocyte casts look like?

Answer 40

These contain WBCs - mostly neutrophils indicats inflam of renal tubes

Question 41

What do cellular - erythrocyte casts look like?

Answer 41

RBC casts will have yellow to orange color, RBC membranes may or may not be visible indicates renale hemorrhage, trauma, bleeding disorders or inflam

Question 42

What are waxy casts?

Answer 42

resemble hyaline, but are usually wider with SQUARE ends gray to colorless and have dull waxy appearance usually highly refractile indicate severe and chronic renal tubular degeneration waxy casts are easily missed unless you have your condenser low and adjust the fine focus of your microscope

Question 43

What are fatty casts?

Answer 43

contain many small droplets of fat have small refractile bodies in the cast common in cats w/ renal dz, and dogs w/ diabetes mellitus lg #'s will be seen w/ renal tubular degeneration

Question 44

What are urine cats?

Answer 44

any type of cast can be stained w/ bilirubin (yellow-brown color) when there is excess amounts of bilirubin in the urine Casts may also contain various crystal types within them

Question 45

What are urine crystals?

Answer 45

Crystalluria - presence of crystals in the urine found in the both and abnormal urine diff types of crystals have diff chemical make-ups depends on pH of urine, genetics identification is based on shape of crystal

Question 46

What factors increase crystal formation?

Answer 46

certain diets, urine concentration (higher USD > more crystals), temperature (cold > more crystals) Alkaline Urine Urinary tract infections in dogs same risks factors for crystal formation as for stone formation

Question 47

What are struvite crystals?

Answer 47

AKA triple phosphate crystals/magnesium ammonium phosphate (MAP) inc formation in alkaline urine (pH 7.0+) - also seen w/ urease prod bacteria (UTIs) Sm #'s normal in D/C - clinically significant when in lg #'s and have clinical signs

Question 48

What do struvite crystals look like?

Answer 48

prism or coffin-lid shape and will have Y formation can form if urine left to sit for long periods struvite can be dissolved w/ diet can be small to very lg

Question 49

What are calcium oxalate crystals?

Answer 49

2 forms, Ca-Ox dihydrate, a square with an X Ca-Ox monohydrate, various shapes and seen w/ theylene glycol toxicity

Question 50

What do Ca-Ox dihydrate crystals look like?

Answer 50

Small box w/ X across various sizess but smaller than struvite Found in urine w/ acidic or neutral pH sm #s normal in Eq, cattle and other herbs In dogs: may be incidental finding if present in low #s, clinically significant if lg #s, risk factors: diet high in Ca and/or oxalate: genetics

Question 51

What do Ca-Ox monohydrate crystals look like?

Answer 51

usually sm, dumb-bell shaped crystals less commonly round disks, or elongated and pointed like a picket fence most commonly seen w/ ethylene glycol toxicity

Question 52

What do urate crystals look like?

Answer 52

uric acid crystals usually diamond or rhomboid shaped crystals, yellow to yellow-brown in color common in dalmations but otherwise rare in C/D

Question 53

What are amorphous crystals?

Answer 53

amorphous phosphate crystals found in alkaline urine amorphous urates similar to ^^ but found in ACIDIC acid colorless, granular precipitate can be artefact from cooling urine

Question 54

What do calcium carbonate crystals look like?

Answer 54

common in horses/rabbits variety of forms - dumbbell shape, striated spheres, cloverleaf shape found in neutral to alkaline urine very rare in D/C, no clinical significance

Question 55

What do ammonium biurate look like?

Answer 55

found in slightly acidic, neutral or alkaline urine brown in color crystals have round shape with long irregular spicules have been called thorn apple crystals associated w/ liver dz (portosystemic shunts)

Question 56

What are sulphonamine crystals?

Answer 56

patients being treated w/ sulfonamides often have them in the urine so check patient hx individual crystals radiating out from the center dark in appearance

Question 57

What do bilirubin crystals look like

Answer 57

pigmented, golden-brown feather like appearance (frost on a window) Found in acidic urine represents an increased urinary concentration of bilirubin may indicate cholestatis liver dz or hemolytic anemia

Question 58

What are cystine crystals?

Answer 58

not common appear to be flat or thin 6 sided (hexagonal) colorless associated w/ renal tubular dy

Question 59

What microorganisms may be found in the urine? Why?

Answer 59

bact, fungi, protozoa organisms not found in healthy urine when collected by catheterization or cystocentesis may be found in free catch samples as contaminants from genital tract and surrounding skin/fur will replicate if left at room temp - refrigerate sample if analysis will not occur in 1hr

Question 60

How might you find bacteria in the urine?

Answer 60

identify under 40x objective report morphology: cocci, rods give arrangement: single, diploid, short chains, occasionally tetrad look for motility: differentiate from brownian movement give #: few, moderate, many, TNTC; when possible, give average #/hpf or range/hpf

Question 61

What does bacteria in the urine indicate?

Answer 61

bact alone DOES NOT indicate a UTI w/ free catch samples - normally an inc in WBCs and some RBCs w/ UTI, pyelonephritic, prostatitis or a pyometra bact most significant when found within WBCs a cysto sample preferred collection with UTI suspected or a urine culture required

Question 62

What does yeast look like in urine?

Answer 62

often confused with RBCs or fat droplets will have characteristic budding and double refractile walls usually a contaminant can be from dermal year infection if it is a free catch sample

Question 63

What do fungi look like in the urine?

Answer 63

rarely found in urine, can be serious if they are found can also be contaminat from enviro with free catch can be filamentous and usually branching

Question 64

What do parasites look like in urine?

Answer 64

can be from fecal contam or parasties in urinary tract pearsonema plica - bladder worm dirofilaria immitis - heart worm dioctophyma renale - kidney worm (dogs)

Question 65

What are mucus threads in urine?

Answer 65

can be confused w/ casts - edges not as well defined as casts resembles twisted ribbon prevalent in equine urine in other anims indicates urethral irritation or contam from genital secretions

Question 66

What does spermatoza look like in the urine

Answer 66

seen in the urine of intact males and recently bred females no clinical significance may cause inc in protein lvls in the urine test strip

Question 67

What are fat droplets in the urine?

Answer 67

very common, highly refractile, spherical bodies that vary in size, may have slight green tinge if you let slide sit for 1 min, droplets will rise to top of drop of urine and not be in the same field of view as other elements not clinically significant

Question 68

What are some common artifacts that we might see in urine?

Answer 68

little signifiance, common when collected from dusty environments or in tall dry grasses Air bubbles, hair, fecal material, plant spores, pollen or other plant material, fibers, dust, starch granules - from gloves, glass fragments from coverslips or slides

Question 69

What are some normal urine results, if these things were to show up

Answer 69

0-3 RBC/hpf – largely dependent on collection method,0-3 WBC/hpf  Few epithelial cells/hpf (more in samples collected by catheterization)  0-1 hyaline or granular casts/lpf in concentrated urine  Fat droplets are c`ommon in dog/cat urine  Spermatozoa in intact males or recently bred females  Bacteria in small numbers when urine collected by free-catch or with poor catheterization technique  Small numbers of crystals (struvite and/or calcium oxalate dihydrate) in cats and dogs  Calcium carbonate and calcium oxalate dihydrate crystals in horses  Mucus strands in equine urine  Environmental contaminants/artifacts

Question 70

What are some abnormal urine constituents?

Answer 70

 >3 RBC/hpf, >3 WBC/hpf, Casts  >0-1/lpf – hyaline or granular casts  The presence of any cast other than hyalin or granular  Large numbers of crystals or the appearance of unexpected crystal types  Parasite ova and microfilaria  Bacteria in cystocentesis samples  Phagocytosed bacteria  Large numbers of yeast or hyphae (watch for contamination)  Increased numbers of epithelial cells or abnormal epithelial cells

Question 71

What is line preparation?

Answer 71

Prepare a urine sample as you would a blood smear, BUT half-way through, lift spreader slide off the bottom slide to form a rectangle shaped sample creates a line of concentrated cellular elements on slide, air dry completely, stain as you would for blood smear examine under oil best for id'ing cells and bact