urinalysis practicum Flashcards
under what maginification are urine cells enumerated?
400x
how many TNTC(too numerous to count) RBC’s be dispersed so other sediment may be evaluated?
2% acetic acid will lyse the RBCs
Casts and ____ go hand in hand…
protein
identify possible causes of a false negative dipstick test for blood.
ascorbic acid
high SG
high nitrite
what crystals appear in acid urine?
ampicillin amorphous urate aspirin bilirubin calcium phosphate calcium oxalate cholesterol cysteine hemosiderin hippuric acid leucine sufonamide tyrosine uric acid x-ray media
which crystals appear in alkaline urine?
ammonium biurate amorphous phosphate calicum carbonate calcium phospahte calcium oxalate triple phosphate
asprine
CS: extremely rare indicates overdose of aspirin
Cause: excess aspirin excreted in urine causing the crystals to form.
cystine
CS: indicate congenital cysinosis or cystinuria. Deposit in tubules as calculi resulting in renal damage.
Cause: pyelonephritits, diet high in animal fat and protein.
bilirubin
CS: liver disease
Cause: formed when large amounts of bilirubin is present.
leucine
CS: aminoaciduria or severe liver disease
Cause: very water soluable so rarely seen
tyrosine
CS: animoaciduria or severe liver disease
Cause: water soluable so rarely seen but found often w/leucine
cholesterol
CS: rare, always accompanied by large amounts of protein and other fats
Cause: nephrotic shyndorme and conditions resulting inchyluria (rupture of lymphatic vessels into renal tubules)
uric acid
CS: can be non-pathogenic but large numbers seen in gout pts. and conditions of increased purine metabolism (cytoxic drugs used in leukemia)
Cause: crystals form as body tries to rid itself of excessive uric acid in the blood possibley caused by over weight, rich diet, exposure to lead or genetic predisposition.
calcium oxalate
CS: non-pathogenic with ingestion of high oxalate foods but also seen in ingestion of antifreeze and severe chronic renal disease.
Cause: oxalic acid (metabolite of ascorbic acid) will combine with Ca2+ in urine to form calcium oxalate.
ampicillin
CS: rare
Cause: indicates large doses of ampilicillian (antibiotic)
calcium phosphate
CS: none
Cause: calcium and phosphate combine in urine to form an insoluable complex
hippuric acid
CS: none
Cause: might be seen in ethylene glycol (antifreeze) intoxication or exposure to toluene in atmosphere
sulfonamide
CS: rare renal damage common
Cause: original drug was insoluable and formed crystals in renal tubules causing damage. Current drugs do not have solubility problems.
x-ray media
CS: none but may be mistaken for cholesterol
Cause:crystals can form in acid urine as body excretes the dye.
triple phosphate
CS: none but can be associated with UTI in alkaline pH.
Cause: Ammonium combines with magnesium and phosphate in alkaline urine to form “coffin lid” crystals.
ammonium biurate
CS: none unless found in fresh urine.
Cause: forms as urine ages. if seen must check collection time.
calcium carbonate
CS: none can be mistaken for bacteria.
Cause: can be seen after large consumption of vegetables.
amorphous urate & amorphous phosphate
CS: none but can make microscopy difficult. Enhanced when urine is refrigerated.
Cause: only be distinguished when acetic acid or heating is added to specimen. urate dissolve when heated, phosphate will not.
RBC’s
CS: increased # indicates renal bleed, either glomerular or tubular.
Cause: glomerulonephritis, pyelonephritis, cystitis, calculi, tumors or trauma. No casts or protein bleed in below the kidney.
WBC’s
CS: inflammation or UTI
Cause: bacterial/paratsitic infection or renal diseases
Eos
CS: discrimination of EOS from WBC often impossible
Cause: acute interstitial nephritis or chronic UTI’s
Lymphs
CS: small # usually present. Large # is significant
Cause: presnet in inflammatory conditions such as acute pyelonephritis or in renal rejection transplant.
monos & macrophages
CS: increase in viral conditions
Cause:drawn to site of inflammation resulting from renal infection or immune reactions
Transitional Epi
CS: indicates inflammation or renal damage if large # seen.
Cause: UTI. clusters/sheets seen after catherization but if no instrumentation used, indicates a pathological process.
squamous epi
CS: none
Cause: specimen contamination.
convoluted renal tubular epi
CS: increased in acute ischemic or toxic renal tubular disease.
Cause: indicates heavy metal or drug toxicity.
collecting duct renal epi
CS: very significanat
Cause: all type of renal disease
oval fat bodies
CS: indicates glomerular dysfunction with renal tubular cells death and leakage of plasma into urine
Cause: renal tubular cells become engorged with fats from tubular lumen or own degenerating intracellular lipids
cyomegalic inclusion bodies
CS: indicates viral infection affecting newborns with liver, spleen and blood disorders and adults with Hodgkins, leukemia & aplastic anemia
Cause: viral inclusions found in nucleus of renal tubular epi cells
hyaline casts
CS: normal in low numbers. High numbers can indicate strenuous exercise, dehydration, fever, stress, renal disease or congestive heart failure (CHF)
Cause: composed of homogenous Tamm-Horsfall (T-H) protein matrix and formed within tubules.
waxy
CS: indicates urinary stasis
Cause: formed when granular cast degenerates as it sits in the renal tubule.
granular cast
CS: finely granular in low #’s can be normal. Coarse granular and broad granular = poor prognosis.
Cause: coarse granular results from degeneration of renal cells and other casts. Broad indicates renal damage.
broad cast
CS: renal failure
Cause: cast forms in dialted convuluted tubules or collection ducts indicating severe urinary stasis.
renal tubular epi cast
CS: renal tubular disease
Cause: renal epi cells become incorporated into the T-H matrix as it sits in the tubule
red cell cast
CS: diagnostic of intrinsic renal disease.. Ocasionally found in healthy people 24-48 hours after contact sports
Cause: RBCs from glomerulus or tubular damage
leukocyte cast
CS: renal inflammation or infection
Cause: glomerulonephritis will also have RBC casts
bacterial cast
CS: hard to see not often diagnosed.
Cause: usually contains WBC’s so often reported out as such.
fatty cast
CS: significant renal pathology, nephortic syndrome or crush injury
hemosiderin & crystals
CS: sulfonamide & Ca oxalate most common. Ass. w/hematuria
Cause: any substance present in tubular lumen can be in casts.
pigmented casts
CS: Hb and myoglobin, yellow to brown with hematuria. Bilirubin: all urine sediment will be yellow-golden brown. Urobilin: yellow-golden but will not color sediment
what is the principle of the reaction of occult blood with dipstick method?
hydrogen peroxide (H2O2) reacts with tetramethylbenzidine (chromogen) in presence of Hgb or myoglobin to produce oxidized chromogen and water.
what is the principle of the reaction for pH with dipstick method?
oxidized dye (yellow) reacts with hydrogen ions to produce hydrogen and reduced dye (green to blue)
what is the principle of the reaction for protein with dipstick method?
an idicatior dye added to protein in pfersence of pH 3.0 will produce a blue green color as hydrogen ions are released from the indicator dye.
what is the principle of the reaction for nitrite with the dipstick method?
with an acid pH, nitrite in urine reacts with para-arsanililc acid to form a diazonium compond which in turn couples with 1,2,3,4 tetrahydrobenzo (h)quinolin-3-ol to produce a pink color
what is the principle of the reaction for glucose with dipstick method?
glucose oxidase catalyzes the oxidation of glucose in urine to from a hydrogen peroxide and gluconic acid. the hydrogen peroxide then oxidizes the chromogen on the pad in the presence of the peroxidase.
what is the reason for a negative dipstick for glucose and a positive clinitest?
a reducing substance is pressent (sucrose)
what is the principle of the reaction for ketones with dipstick method?
acetoacetic acid in alkaline medium reacts with sodium nitroprusside to produce a color change from beige to purple.
what is the purpose of the principle of the reaction for urobilinogen with dipstick method?
URO reacts with Ehrlich’s reagent (paradimethylaminobenzaldehyde) to form a red colored compound (light orange-pink to dark pink)
what is the principle of the reaction for bilirubin with dipstick method?
bilirubin reacts with a diazonium salt (diazotized 2,4 dichloroaniline) in acid medium to for an azodye (color changes from light tan to beige)
what is the princple of the reaction for leukocyte esterase with dipstick method?
leukocyte seterases cleave ester to form an aromatic compound which then combines with diazonium salt in acid pH to produce an azodye ( color changes from beige to violet)
what is the principle of the reaction for specific gravity with dipstick method?
ionic solutes in urine cause protons to are realeased, the pH decreases and produces a color change of the bromthymol blue indicator from blue-green to yellow-green.
how many amorphous be dispersed so other sediment may be evaluated?
2% acetic acid gets rid of amorph phosphate. heat to get rid of amorph urates
what organism may be found in the urine of diabetics?
yeast
what type of urine specimen provides an overall pictures of the pts. health?
random specimen
name a few type of preservatives for urine specimens?
- refrigeration
- commercial transport tubes (boric acid)
- thymol preserves sediments
- formalin-cellular preservation, will cause false-negative in blood & urobili reagent tests; used in cytology.
what is the clinical significance of bilirubin &/or urobilinogen in a urine specimen?
not normal, can indicate hepatitis, cirrhosis or biliary obstruction, but negative in chronic liver disease.
can you report a neg urobilinogen?
no
what is the SG of normal urine?
1.002-1.030
what is the significane of ketones in the urine?
indictes fat metabolism resulting from starvation or deficiency in carbohydrate metabolism.
how is urine osmolality determined?
measured by freezing point depression or vapor pressure osmometer. unaffected by heavy molecules, all solutes contribute equally. Normal value is 275-900 mOsm/kg of water.
what are the findings on the dipstick with a UTI?
protein: small
blood +
leukocyte +
nitrite +
what are the findings on the dipstick with HTR?
elevated urobilinogen but not bile.
what is an addis count?
count of # WBCs, RBCs and casts in a 12 hr overnight period when patient is not eating or drinking; used to follow progress of renal disease, not commonly done.
define sensitiviy
ability of a test to pick up the lowest level of pathological concentration, but not normal urine levels
define specificity
ability of test to react specifically to the substance being tested and no other.
define glitter cell
neutorphils in hypertonic solution swell causing Brownina movement in cytoplasmic granules
what urinary crystal appears in more forms than any other crystal
uric acid crystal
how many RBCs and yeast plus WBCs and renal epi cells be differentiated?
acetic acid lyses RBC, but not yeast, WBC or RE and it will accentuate nuclei of WBC. Toluidine blue will also accentuate WBC nuclei. RE have large, dense nuclei and polygonal shape where WBCs are RBCs are spherical. yeast vary in size, are not biconcave and usually are budding.
what sugar is a non-reducing sugar?
sucrose
how may myoglobin and Hgb be differentiated?
80% ammonium sulfate precipitation: Hgb precipitates out of solution by myoglobin remains soluble.
what is the best way to find urinary casts in a microscopic field?
low power, dim light
what is the most common constituent of renal calculi?
calcium oxalate
