Urinalysis Flashcards
what does a complete UA consist of?
physical examination, chemical examination, microscopic examination
normal physical examination color
yellow, amber, straw
what does a milky color urine indicate?
pus, bacteria, fat
what does red/smoky brown urine indicate?
blood
what does yellow foam urine indicate?
bile pigments
what does white foam urine indicate?
albumin
what does coca-cola colored urine indicate?
Acute glomerulonephritis; strep. infections
normal physical examination appearance/clarity
clear
abnormal appearance/clarity
reported as turbid or extremely turbid
normal urine odor
aromatic
abnormal urine odor
ammoniacal, fruity, stale water, foul
ammonical urine odor
bacterial decomposition of urine; smells like cleaning supplies; urinary retention
fruity urine odor
ketone bodies; diabetes mellitus
stale water urine odor
advanced kidney disease
foul urine odor
bacteruria (UTI)
what does the chemical examination assess?
specific gravity, pH, protein, glucose, ketones, blood, leukocyte esterase, nitrite, bilirubin, and urobilinogen
specific gravity
measure of dissolved substances in urine (density or urine/density of water)
normal specific gravity levels
1.005-1.030
why would specific gravity be low?
excessive hydration, diabetes insipidous
why would specific gravity be high?
dehydration, diabetes mellitus, fever
normal pH for urine
4.5-8.0
what does a low pH indicate?
acidosis, fevers, high protein diets
what does a high pH indicate?
alkalosis, cystitis
proteinuria
protein in urine
what is proteinuria mostly indicative of?
renal disease
trace proteinuria
generally not clinically significant
functional proteinuria
not associated with easily demonstrable systemic or renal damage (increased renal blood flow)
orthostatic proteinuria
increased protein in urine only when an individual is in an upright position
organic proteinuria
prerenal, renal, postrenal
glucosuria
glucose in the urine
normal renal threshold for glucose
180 mg/dL
what does glycosuria without hyperglycemia indicate?
pregnancy
what does glycosuria with hyperglycemia indicate?
diabetes mellitus
ketonuria
ketones in urine
causes of ketones in urine
type I diabetes mellitus, starvation, severe dehydration, fever in kids
hematuria
blood in urine as a result of trauma or irritation
hemoglobinuria
lysis of RBCs in urinary tract, intravascular hemolysis, or transfusion reactions
myoglobinuria
muscular destruction that may appear in hypothermia, convulsions, extensive exertion (rhabdomyolysis)
what could cause a false negative results of hematuria?
high dose of vitamin C
pyuria
presence of WBCs, inflammation, leukocyte esterase
what causes nitrite in urine?
gram negative bacteria; they have a reductase that takes it from nitrate to nitrite, incubation takes ~4hr (E.Coli)
bilirubinuria
bilirubin in urine
causes of bilirubinuria
biliary tract obstruction, liver disease, cholelithiasis; conjugated bilirubin
urobilinogen in urine
similar significance to bilirubin, small amount is normal, could get false + from warm urine
microscopic examination
done on centrifuged urinary sediment
main pathological elements of the microscopic examination
RBCs: 0-2 HPF
WBCs: 0-5 HPF
Casts
less important elements of microscopic examination
yeasts, crystals, epithelial cells
best specimen of microscopic examination
first morning urination, midstream
causes of RBCs on microscopic exam
nephrolisthiasis, AGN, GU malignancy, benign prostatic hyperplasia, cystitis, pyelonephritis, benign hematuria, contamination
clinically significant hematuria
> 2 HPF
pyuria in microscopic exam
indicates inflammation, may originate anywhere in urinary tract, WBC casts are definite evidence that urinary WBCs originate in the kidney
causes of pyuria in microscopic exam
pyelonephritis, renal TB, cystitis
clinically significant pyuria
> 5 HPF
epithelial cells in microscopic exam
> 10 squamous epithelial cells/low-power field is a sign of contamination
casts
protein conglomerates in shape of renal tubules
hyaline casts
little concern
waxy casts
advanced renal failure
RBC cast
acute glomerulonephritis
WBC cast
acute pyelonephritis
fatty cast
advanced renal disease, nephrotic syndrome
pseudocasts
fibers, dust; fake-outs
triple phosphate crystals
found in alkaline urine, no clinical significance, coffin lid
calcium oxalate crystals
found in normal urine, no clinical significance, cross/X