Urinalysis Study Guide Flashcards
Under what magnification are urine cells enumerated?
400x
How may, too numerous to count, rbc’s is dispersed so other sediment can be evaluated?
2% acetic acid
lyse rbc’s
Casts and ? go hand in hand in a urine sediment
protein
Possible causes of false negative dipstick test for blood
ascorbic acid
high SG
high nitrite
Which crystals appear in acid urine
KNOW
Which crystals appear in alkaline urine
KNOW
Can indicate congenital cystinosis or cystinuria, tend to deposit in tubules as calculi resulting in renal damage
can be caused by pyelonephritis, diet high in animal fat and protein
Cystine crystals
Indicates liver disease
formed when large amounts of bilirubin is present in urine
Bilirubin crystals
Indicates aminoaciduria or severe liver disease
very water soluble so rarely seen
Leucine crystals
Indicates aminoaciduria or severe liver damage
water soluble so rarely seen, but found more often than leucine
Tyrosine crystals
Rare: aways accompanied by large protein and other fats
seen in nephrotic syndrome and conditions resulting in chyluria: rupture of lymphatic vessels in renal tubules
Cholesterol crystals
Non pathologic, except in large amounts seen in gout and conditions of purine metabolism (cytotoxic drugs)
crystals form as body tries to rid itself of excess in the blood caused by overweight, rich diet, exposure to lead or genetic predispostition
Uric acid crystals
Non pathologic; with ingestion of high oxalate foods but also seen in ingestion of antifreeze and severe renal disease
oxalic acid (metabolite of ascorbic acid) will combine with Ca2+ in urine to form. . .
Calcium oxalate crystals
Rare
Indicates larege doses of the antibiotic
Ampicillin
Not clinically significant
might be seen in ethylene glycol (antifreeze) intoxication, or exposure to toluene in atmosphere
Hippuric acid
Extremely rare; indicates overdose if seen; salicylic acid
excess excreted in urine and may crystalize in acid urine
Aspirin
Rare; renal damage uncommon
original drug was insoluble and formed cyrstals in renal tubules. Current drugs are soluble
Sulfonamide
Not clinically significant; mistaken for cholesterol
form in acid urine as body excretes the dye
X-ray media
No clinical significance but can be associated with UTI in alkaline urine
ammonium combines with magnesium and phosphate in alkaline urine to form “coffin lid” crystals
Triple phosphate
Not clinically significant unless found in fresh urine (very rare). Can be mistaken for sulfanomide.
forms as urine ages. check collection time of specimen
ammonium biurate
No clinical significance. Can be mistake for bacteria
seen after lare consumption of vegetables
Calcium carbonate
Not clinically signficant. enhanced when urine has been refrigerated
Only distinguished by acetic acid or heating to 60C
Amorphous urate - dissolves when heated
Amorphous phosphate - does not dissolve when heated
Increased indicates renal bleed, either glomerular or tubular. Associated with casts and proteinuria
Indicates glomerularnephritis, pyelonephritis, cystitis, calculi, tumors, or trauma. If no cast or proteinuria, bleed is below the kidney or may be contamination
RBCs
Increased indicates inflammation of urinary tract
indicates bacterial/parasitic infections or renal diseases *ex; glomerularnephritis, chlamydia, mycoplasmosis, TB, trich, mycoses)
WBCs
Hard to differentiate from other WBC
Indicates acute interstitial nephritis (AIN) or chronic UTI
Eosinophils
Normally present in urine in small amounts. Not normally distinguished from WBCs but large amount is significant.
Present in inflammatory conditions, such as acute pyelonephritis or in renal rejection transplant.
Lymphocytes
Increased viral conditions
drawn to site of inflammation resulting from renal infection or immune reactions
Monocytes, Macrophages
Indicates inflammation or renal damage if found in large amounts.
Can be UTI. Clusters/sheets seen after catheritization but if no instrumentation used, indicates pathological process
Transitional epithelial
Not clinically significant
Indicates specimen contamination
Squamous epithelial
Increased in acute ischemic or toxic renal tubular disease
indicates heavy metal or drug toxicity
Convoluted renal tubular epithelial
Very significant
All types of renal disease, such as, mehpritis, acute tubular necrosis, kidney transplant rejection, salicylic acis poisoning
Collecting duct renal epithelial
Indicates glomerular dysfunction with renal tubular cell death and leakage or plasma into urine. Associated with casts and protein
Renal tubular cells become engorged with fats from tubular lumen or own degenerating intracellular lipids
Oval fat bodies
Indicates viral infection affecting newborns with liver, spleen and blood disorders, and adults with Hodgkins, leukemia and aplastic anemia
Viral inclusions found in nucleus of renal tubular epithelial cells
Cytomegalic Inclusion bodies
CMV
Normal in low numbers. High numbers can indicate strenuous activity, dehydration, fever, stress, renal disease or congestive heart failure
Composed of homogenous Tamm-Horsfall protein matrix and formed within tubules
Hyaline cast
Indicates urinary stasis
Formed when granular cast degenerates as it sits in renal tubule
Waxy cast
Finely granular in low numbers can be normal. Coarse granular and broad granular indicates poor prognosis. Associated with renal tubular epithelial cells and proteinuria
coarse granular results from degeneration of renal cells and other casts. Broad granular indicates renal damage
Granular cast
Renal failure, increase amount is poor prognosis
Cast forms in dilated convoluted tubules or collecting ducts indicating severe urinary stasis
Broad cast
Indicates renal tubular disease. Associated with proteinuria and granular casts
Become incorporated into the T-H matrix as it sits in tubule (urinary stasis)
Renal tubular epithelial cast
Diagnostic of intrinsic renal disease. Associated with proteinuria. Occasionally found in healthy people 24-48 hours after contact sports
glomerular and tubular damage
RBC cast
Indicates renal inflammation or infection
Glomerularnephritis will also have rbc casts, pyelomephritis with also have proteinuria and heamturia
WBC cast
Not often ID’ed because difficult to see, diagnostic of pyelonephritis
Usually contains WBC so often reported as WBC cast
Bacterial cast
Significant in renal pathology: nephrotic syndrome or severe crush injury
Usually contained with hyaline or granular matrix and associated with proteinuria
Fatty cast
Sulfonamide and Ca oxalate most common. associated with hematuria
Any substance present in tubular lumen can be in casts
Hemosiderin
Pigments cast
Hgb, myoglobin: yellow to brown, with hematuria
Bilirubin: yellow to brown in all urine & sediment
Urobilinogen: yellow-golden urine but not sediment
Phenazopyridine: urinary pain killer, brown to reddish brown
Hydrogen peroxide, H2O2, reacts with tetramethylbenzidine, chromogen, in presence of hemoglobin or myoglobin to produce oxidized chromogen and water
Occult blood
Oxidized dye, yellow, reacts with hydrogen ions to produce hydrogen and reduced dye, green-blue
pH
An indicator dye added to protein in presence of pH 3.0 will produce a blue-green color as hydrogen ions are released from indicator dye
Protein
With acid pH, urine reacts with para-arsanilic acid to form a diazonium compound, which in turn couples with 1,2,3,4-tetrahydrobenzo(h)quinolin-3-ol to produce a pink color
Nitrite
Glucose oxidase catalyzes the oxidation of glucose in urine to forma hydrogen peroxide and gluconic acid. The hydrogen peroxide then oxidizes the chromogen on the pad in the presence of the peroxidase
Glucose
What is the reason for a negative dipstick on glucose and a positive clinitest?
reducing substance other than glucose present; galactose, sucrose
Acetoacetic acid in an alkaline medium reacts with sodium nitroprusside (nitroferricyanide) to produce a color change from beige to purple
Ketones
React with Ehrlich’s reagent (para-dimethylaminobenzaldehyde) to form a red colored compound, light orange to dark pink
Urobilinogen
Reacts with a diazonium salt (diazotized 2,4-dichloroaniline) in acid medium to form an azodye, color change from light tan to beige
Bilirubin
Cleaves ester to form an aromatic compound which then combines with diazonium salt in acid pH to produce an azodye, color change from beige to violet
Leukocyte esterase
Ionic solutes in urine cause protons to release from a polyelectrolyte. As protons are released, the pH decreases and produces a color change of the bromthymol blue indicator from blue green to yellow green.
SG
How may amorphous be dispersed so other sediment may be evaluated?
2% acetic acid to rid amorphous phosphate
heat to 60C to get rid of amorphous urate
What organism may be found in the urine of diabetics?
yeast
What type of specimen provides an overall picture of the patients health?
Random specimen
can run routine analysis up to 24 hours
refrigeration
preserves urine for longer time at RT; routine analysis
Commercial transport tubes; boric acid
preserves sediment, inhibits bacteria and yeast
Thymol
cellular preservation, will cause false-negative in blood and uro tests; used in cytology
Formalin
cellular preservation; used in cytology
Saccomanno’s fixative
Unacceptable preservatives for urine
Acids; HCl, glacial acetic acid
Sodium carbonate
What is the clinical sign of BIL and URO in a urine specimen?
BIL: not normal, can indicate hep, cirrhosis or biliary obstruction, but neg in chronic disease
URO: increased amount can indicate hep, cirrhosis or hemolytic states(PA). Decreased in chronic liver disease(cannot report negative URO) small amount is normal
What is the SG of normal urine?
1.002-1.030
What is the significance of ketones in the urine?
indicates fat metabolism resulting from starvation or deficiency in COH metabolism
How is urine osmolality determined?
measured by freezing point depression or vapor pressure osmometer. Unaffected heavy molecules, all solute contribute equally. Normal value is 275-900 mOsm/kg of water
What are the findings on the dipstick with a UTI?
protein: small
What are the findings on the dipstick with a HTR?
elevated URO but not bile
Count of # of WBC, RBC, and casts in a 12 hr overnight period when a pt is not eating or drinking: used to follow progress of renal disease, not commonly done
Addis count
Ability of a test to pick up the lowest level of pathological concentrations, but not normal urine levels
Sensitivity
Ability of test to react specifically to the substance being tested and no other
Specificity
Neutrophils in hypertonic solution swell causing Brownian movement in cytoplasmic granules
Glitter cells
What urinary crystals appear in more forms than any other crystal?
uric acid
How may RBC and yeast, plus WBC and renal epilthelial cells be differentiated?
acetic acid: lyses RBC but not yeast, WBC or RE and it will accentuate the nuclei of WBC
Toluidine blue also accentuates the nuclei of WBC
RE have lg dense nuclei and polygonal shape
Yeast vary in size but are not concave and are usually budding
What sugar is a nonreducing sugar?
sucrose
any sugar with an aldehyde group or can form one
How may myoglobin and hemoglobin be differentiated?
80% ammonium sulfate precipitation: Hgb precipitates out of solution but 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
