Urinalysis Flashcards
GFR = best indicator of ___
overall renal function
best indicator of overall renal function = ?
GFR
GFR can depend on ___
hydration status
most of fluid reabs along with proteins to achieve homeostatic balance
3 parts of examining urine
1) UA and micro
- visual
- chemical
- microscopic
Urine specimens for urinalysis must be tested within ___
24 hr specimens are ___ for urinalysis testing
2 hours of specimen collection
unacceptable
for culture, you need a ___
if antibotic therapy is noted, lab will process with ___
midstream clean catch
longer incubation
urine collection for 24 hrs or timed cocmponents
1) preservatives
2) adequately pre-hydrate patient
procedure for 24 hr urine collection
1) void before begin
2) start collecting
3) exactly 24 hrs void one more time
criteria for specimen evaluation
1) label
2) preservative
3) voided v. suprapubic vs. cath
4) first morning void usu
Urinalysis method
1) mix specimen
2) observe physiochemical prop
3) perform reagent dipstick
4) centrifuge
automated
visual examination of 24 hour collection ddx polyria (> 2000 mL SG
1) decr ADH
2) defective renal salt/water reabsorption
3) osmotic diuresis (Diabetes)
1) prerenal, postrenal, or renal
yellow-green brown
orange-red brown
pink-red
dark brown/black
1) bile pigments = bilirubin
2) urobilinogen
3) hematuria, hemoglobin, myoglobin, porphyria
4) methemoglobin, rhbdo,
clarity (turbidity)
1) ddx chyluria
2) ddx lipiduria
1) lymphatic flow obstruction = filariasis
2) fat globules in nephrotic syndrome, trauma
recommendations for reagent strips
1) check
2) test urine ___
3) urine samples at ___ temp
4) follow exact ___ for each chem test
1) check manufacturer’s directions with lot #
2) test urine ASAP
3) urine samples at room temp
4) timing recommendations
define specific gravity
specific gravity measures ___
ddx SG 1.035
proportion of dissolved solids per volume (urea, NaCl, sulfate, phosphate)
concentrating ability of kidneys
1) polydipsia, diuretic, diabetes
2) dehydration, diabetes, proteinuria, CHF, addison’s
define osmolality
after dehydration, osmolality …
usu __ in parallel with specific gravity unless ___
of particles of solute/volume
incr to 3-4x plasma
incr
glucose/protein
specific gravity > 1.01 suggests…
isothenuria 1.008-1.012 suggest…
intact tubular function and PRE-RENAL
renal tubular dysfunction = renal tubular acidosis
hallmark of renal tubular acidosis is..
alkaline urine
or with UTI = urea splitting organism (proteus)
definition of proteinuria
normal daily value
ddx proteinuria
> 150 mg/dL or btwn 2+ - 3+
postural proteinuria
proteinuria in elderly
nephrotic syndrome
overflow = multiple myeloma
caveats of protein
1) dipstick method sensitive to albumin only NOT GLOBULIINS
2) alkaline = falsely low results
3) bence jones = multiple myeloma
glucose is usually ___ in urine
undetectable
glucose in kidney caveats
1) filtered by ___ and nearly entirely ___
2) positive in …
3) false positive if ___
4) vitamin C can lead to …
5) copper reduction test
1) glomerulus; absorbed
2) diabetes, pregnancy, endocrine, pancreatic
3) collection jar open
4) false negative
5) for reducing sugars in pediatric patients –> TLC
ketones normally ___
positive anytime when ___
1) undetectable
2) incr in lipid metabolism (diabetes, alcoholism, cirrhosis, exercise)
ddx of ketones
signs of nondiabetic ketonuria
diabetic ketonuria
fever, vomiting, cachexia
dipstick tests for peroxidase-like activity of hemoglobin ___
hemosiderin present when …
hemosiderin indicates …
interference from vitamin C
2-3 days after hemolytic episode
renal tubules catabolize hgb to ferritin and hemosiderin
if no RBCs in urine
if free RBCs in urine
if RBC casts in urine
free hgb or myoglbin
non-glomerula hematuria
glomerular hematuria
if renal dysfunction –> nephritic syndrome
if you see incr urinary bilirubin (dark urine)
if you see incr early urinary bilirrubin or incr later urobilinogen
if see incr urobilinogen
obstruction to blood flow
liver damage, hepatitis, cholestasis
hemolysis, hemolytic anemia
if nitrate reduced to nitrite
indirect test for UTI
positive result for nitrite suggests ___ in urine
combine with ___ to definitvely diagnose UTI
negative nitrite test means…
gram neg (high specificity) unless container has been open to air leukocyte esterase
does not rule out (low sensitivity)
___ is an indirect measure of # of neutrophils in urine
leukocyte esterase
more sensitive but less specific for UTI (anything that incr leukocyte (vag infection) will incr leukocyte esterase
leukocyte esterase has higher ___ but lower ___ for UTI in comparison to nitrite
sensitivity
specificity
other sources of neutrophils from UA
or esterases
vaginal secretions, glomerulonephritis
eosinophils –> false positive
3C’s and O of microscopic examination of urine
Cells = epithelial, RBC, WBC
Casts = cellular, noncellular
Crystals
Organisms (bacteria)
Dysmorphic, distorted RBC suggests… often with ..
Pyuria does not prove ____ indicates ___
renal tubular epith cells indicate
oval fat body indicates
glomerular origin
RBC casts
infection, indicates inflammation
renal diseases
nephrotic syndrome
Casts are due to ___
Tamm-Horsfall protein congealed
Hyaline casts are …
nonspecific (dehydration, exertion)
Waxy casts assoc with …
advanced chronic renal failure
red cell casts suggest
glomerular disease
WBC casts suggest
inflamm (pyelo, AIN, interstitial nephritis)
tubular casts suggest
ATN
viral disease
drug exposure
granular casts suggest
immune complexes
fatty casts suggest
nephrotic syndrome
crystals are very ___
diagnostically significant?
common
NO
URIC ACID CRYSTALS …
chemo
Lesch-nyhan
calcium oxalate
ethylene glycol toxicity
triple phosphate “coffin lids”
proteus UTI
cystine crystals
cystinuria in pediatric
RBC can come from ..
dysmorphic RBC sign of disease affect…
any point in urinary tract
high in urinary tract (NOT URETER, BLADDER, URETHRA)
because it is most concentrated, the ___ is preferred specimen for analysis
first morning voided urine
some tests require a timed 12-24 hr urine sample but these are not suitable for ___
routine urinalysis
__ and ___ reflect concentraitng ability of kidneys
specific gravity
osmolality
after a period of dehydration, the osmolality should be ___ times plasma
3-4x
proteinuria greater than __ indicates nephrotic syndrome but may be systemic disease
> 3.
__ seen in diabetic individuals but also in ___
ketones
high fever, cachexia, fasting
the __ and ___ tests used to help identify UTI
positive results confirmed by ___
nitride
leukocyte esterase
microscopic analysis of urine and culture
