4. Microscopic Exam Flashcards
“macroscopic screening”
protocols whereby microscopic examination of the urine sediment is performed only on specimens meeting specified criteria
centrifugation speed (RCF and RPMs)
400-450 RCF
1500-2000 RPMs
calculation for RCF
RCF = (1.118 x 10^-5)(radius of rotor head in cm)(RPM^2)
centrifuge for —- min
5
volume used for microscopic exam
0.5 mL - 1.0 mL
concentration factor =
concentration factor = volume of urine centrifuged/sediment volume
examined on low power
SECs
casts
mucus
how do stains work?
change the refractive index of sediment
most frequently used stain
Sternheimer-Malbin
crystal violet + safranin O
Sternheimer-Malbin
function of Sternheimer-Malbin
IDs WBCs, epithelial cells, casts
0.5% solution metachromatic stain
toluidine blue
function of toluidine blue
enhances nuclear detail
diff. WBC and renal tubular epithelial cells
lyses RBCs; helps differentiate
2% acetic acid
oil red O + sudan III
lipid stain
function of lipid stain
stain fats except cholesterol
methylene blue + eosin Y
hansel stain
function of hansel stain
IDs eosinophils
drug-induced allergic rxn
function of prussian blue stain
ID structures containing iron
IDs hemosiderin
preparation of permanent slides for detecting & monitoring renal disease
cytodiagnostic urine testing
function of Papanicolaou’s stain
cytodiagnostic urine testing
how does phase contrast work?
converting variations in refractive index to variation in contrast
function of polarizing microscopy
ID of cholesterol in oval fat bodies, fatty casts, and crystals
“maltese cross” pattern and crystals
Produces a 3-D microscopy image and layer-by-layer imaging of a specimen
Interference-contrast
hematuria clinical significance
Glomerulonephritis
Acute infections
Toxic and immunologic reactions
Malignancies
Contamination (menstruation)
Strenuous exercise
RBC stacking
rouleaux
messed up RBCs
dysmorphic forms
possible explanation for + blood on dipstick but = RBC on microscopic
myoglobin
clumps of WBCs associated with…
proteinuria
glitter cells are in ——- urine
hypertonic/dilute
appearance of WBCs in elderly patients or those on chemo
“Blebs” (vacuoles) and finger/wormlike projections (myelin forms)
explanation for = LE on dipstick but + WBC on microscopic
lymphocytes
abnormal epithelials clinical significance
Pyelonephritis
Toxic reactions
Viral infections
Transplant rejection
Secondary effects of glomerulonephritis
bladder cells
transitional/urothelial cells
transitional cells origin
lining of the renal pelvis, ureters, bladder, and upper urethra
syncytia
sheets of transitional epithelials seen after catheterization
renal tubular epithelial cells origin
linings of renal tubules
RTEs can indicate ——-, except in this population
tubular necrosis
newborns (normal)
renal fragments
3 or more collecting duct RTEs
oval fat bodies
RTEs that are filled with absorbed lipids
OFB clinical significance
glomerular dysfunction with renal tubular cell death and leakage of plasma components (protein and fat) into the urine
if RTE or OFB are present…
protein and casts should also be present
bacteria without WBCs can indicate…
poor specimen handling
yeast are seen in ——— patients because…
diabetic
↑ glucose
pseudohyphae
mycelial elements
parasites in urine
Trichomonas vaginalis
Schistosoma haematobium ova
Enterobius vermicularis ova
males are often asymptomatic carriers
trich
parasite from bladder wall mucosa
Africa/middle East
S. haematobium
parasite from fecal contamination
pinworm E. vermicularis
sperm clinical significance
- sex
- male infertility
- retrograde ejaculation
- SA (children, nursing home etc)
major constituent of mucus
uromodulin
only elements found in sediment that are unique to the kidney
casts
casts reflect ———
and are seen with —— or ——
status of renal tubules
urinary protein levels
urinary stasis
normal casts
hyaline
granular
casts clinical significance (general)
- renal disease
- diuretic therapy
- athletic pseudonephritis
major constituent of casts
uromodulin/Tamm-Horsfall protein
uromodulin production ↑ during…
exercise
stress
broad casts indicate…
tubular distension
factors that enhance cast formation
- ↓ pH
- ↑ in solute concentration
- ↓ in rate of urine flow (urinary stasis)
- Proteinuria (particularly albumin)
cylindruria
casts in urine
hyaline cast composition
uromodulin
hyaline cast clinical significance
Strenuous exercise
Dehydration
Emotional stress
Glomerulonephritis
Pyelonephritis
Chronic renal disease
Congestive heart failure
RBC cast clinical significance
Acute glomerulonephritis (Strep sequelae)
Tubular damage
Strenuous exercise
Incompatible blood transfusions
WBC cast clinical significance
Pyelonephritis (upper UTI)—bacteria +
Acute interstitial nephritis—bacteria =
bacterial cast clinical significance
pyelonephritis
RTE cast clinical significance
renal tubular damage
granular cast composition
disintegrated cell casts
granular cast clinical significance
Normal
Exercise
Renal disease
waxy casts indicate…
extreme urine stasis, indicating chronic renal failure
formation of waxy cast
degeneration of the hyaline cast matrix and any cellular elements or granules contained in the matrix
casts that do not polarize
waxy
waxy cast clinical significance
Chronic renal failure
Tubular obstruction
Acute renal disease (Glomerulonephritis, Nephrotic syndrome)
Malignant HTN
Renal allograft rejection
fatty casts are seen with…
OFBs and free fat droplets
fatty casts clinical significance
Nephrotic syndrome
Toxic tubular necrosis
DM
Crushing injuries
broad casts are mostly either —– or —– casts and indicate…
granular or waxy
extreme urinary stasis
pathologic crystals (organic + iatrogenic) are formed in —– urine
acidic
factors that enhance crystal formation
↑ concentration of solute in urine
pH of urine
Urinary stasis allowing time for formation
↓ Temperature
normal crystals seen in acidic urine
- amorphous urates
- uric acid
- acid urates
- sodium urates
- calcium oxalate
normal crystals seen in alkaline urine
- amorphous phosphates
- triple phosphate
- calcium phosphate
- calcium carbonate
- ammonium biurate
abnormal crystals
- cystine
- cholesterol
- leucine
- tyrosine
- bilirubin
- radiographic dye
- sulfa
- ampicillin
- hemosiderin
- hippuric acid
uric acid crystals abnormal numbers
Increased levels of purines and nucleic acids (diet)
Gout
Chemotherapy
Kidney stones
acid urates + sodium urates abnormal numbers
gout
calcium oxalate abnormal numbers
foods (tomatos, asparagus, vit C)
kidney stones
ethylene glycol poisoning
ethylene glycol antidote
🥂
triple phosphate abnormal numbers
UTI from urease + bacteria
calcium phosphate/carbonate abnormal numbers
renal calculi
ammonium biurate abnormal numbers
iatrogenically induced
improperly handled urine
cystine crystals clinical significance
Metabolic disorder that prevents reabsorption of cystine by the renal tubules (cystinuria)
Renal tubular damage
Renal calculi
cholesterol clinical significance
Lipiduria
Nephrotic Syndrome
leucine clinical significance
IEM
severe liver disease
seen with tyrosine
tyrosine clinical significance
IEM
severe liver disease
seen with leucine and + bilirubin
bilirubin clinical significance
hepatic disorders
viral hepatitis
usually makes iatrogenic crystals go away
adequate patient hydration
hemosiderin seen when?
2-3 days after severe hemolytic episode
hippuric acid clinical significance
ethylene glycol poisoning
starch seen in…
contamination from gloves, talcum powder