Urinalysis Flashcards
What is used to analyze sediment in urine? The supernatant?
sed = light microscopy sup = dipstick
Wy is the urine centrifuged?
to produce supernatant and urinary pellet
Specific gravity is determined by:
number and weight of solutes
Osmolality is determined by:
ONLY the number of solutes
Specific gravity is NOT a marker of how concentrated a sample is when:
abnormal numbers of heavy solutes are present in urine (e.g. contrast dye)
What are the specific gravity and osmolality of a maximum dilute urine sample?
1.002
50-100 mOsm/kg
In metabolic acidosis, urine pH is less than:
5.3
Urine pH >7.5-8.0, suggests:
UTI with urea splitting bacteria (such as proteus)
How does hyperglycemia cause glycosuria?
increases filtered load to greater than the reabsorptive capacity of proximal tubule
What does glycosuria in the presence of normal blood glucose (renal glycosuria) imply?
PT dysfunction
When are ketones often present?
fasting, DKA, and AKA
How do increased plasma ketoanions lead to ketonuria? How is ketonuria diagnosed?
filtered load exceeding proximal tubular reabsorptive capacity
Dipstick specific for acetone and acetoacetate
Elevated levels of plasma conjugated bilirubin lead to:
urinary excretion
_______ bilirubin is water soluble, which ______ bilirubin is insoluble.
Conjugated
Unconjugated
Which type of bilirubin will NOT be present in urine?
unconjugated– non water sol
Nitrite is (present/absent) in normal urine.
absent
Positive nitrite suggests:
UTI with nitrate reducing bacteria
(gram negative)
*Gram negative bacteria = most common uropathogens
What is leukocyte esterase and how is it measured in urine?
Produced by neutroohils, and positive, when there are increased numbers of neutrophils in the urine
Dipstick (detects a neutrophil-specific leukocyte esterase)
What is normal excretion of protein?
<150 mg/day
What is Glomerular Proteinuria associated with?
increased permeability for protein in the glomerular capillary wall
(especially albumin)
What test detects all protein in the urine?
Sulfosalicylic acid test
How and where are low molecular proteins filtered and normally reabsorbed? What if they are not reabsorbed?
pinocytosis
proximal tubule
proximal tubular dysfunction
What is overflow proteinuria? What will you see via urine dipstick?
- Excess production of low molecular weight proteins
- increased filtered load exceeds reabsorptive capacity of PT
dipstick test:
positive for sulfosalicylic acid
negative for albumin
What is a “spot” urine sample?
ratio of urine protein over creatinine (both measured as mg/dl) in a “spot” urine sample
**reliable estimate of quantitative proteinuria
Urine dipstick is normally (positive/negative) for blood.
negative
Most common cause of positive dipstick for blood is:
presence of rbc’s in urinary sediment
Dipstick tests are sensitive to:
free hemoglobin and myoglobin
RBC
What are 5 characteristics of renal hematuria?
- Dipstick positive
- RBC’s in sediment, some dysmorphic
- RBC casts
- Absence of clots
- Often associated with proteinuria
What are 3 characteristics of non-renal hematuria that are different from renal hematuria?
1 .no RBC cats
- no proteinuria
- no abn shaped RBCs
Describe urinary WBC’s:
Granular cytoplasm
irregular nucleus
“glitter cells” (in polarized light?)
What conditions will you see urinary WBC’s in?
- UTI
- pyelonephritis
- allergic interstitial nephritis
- intense glomerulonephritis
Urinary casts represent precipitates of:
protein forming in the lumen of tubules
Where is Tamm-Horsfall protein formed, and what does it do?
by thick ascending limb of Henle cells
forms the matrix of all casts
What are the only normal casts?
What type of cast contains cellular debris?
hyaline
granular
Lipiduria is (present/absent) in normal urine.
absent
What is lipiduria associated with? What causes it?
heavy proteinuria (nephrotic syndrome
presence of lipoproteins
What features of lipiduria may be noted using polarizing light?
Maltese crosses
oval fat bodies
fatty casts
