Wk 2: Urinalysis Flashcards
Describe how a sample should be collected
Clean catch aka midstream specimen
Area around the urethral meatus should be cleaned
Patient should start urinating out of the cup and then move the cup into the stream
Minimizes contamination from skin bacteria and other cells
Contaminated sample cannot reliably diagnose UTI
Re-obtain the sample
In patients with indwelling catheter, the urine sample should be obtained from the _________ rather than the __________________ to represent a more recently produced sample
tubing; collection bag
The three main components of urinalysis are?
1) Gross assessment: Color, clarity, odor
2) Dipstick test: Reagent strips that give semiquantitative assessment on series of tests
Varies somewhat by manufacturer
3) Microscopic exam
Examination of urine sediment after urine sample has been centrifuged
True or false: a urine sample can also be sent for culture if necessary
True
List some values you can get from a urine sample
pH
Specific gravity
Protein
Leukocyte esterase
Nitrite
Glucose
Ketones
Bilirubin
Urobilinogen
Crystals
Casts
WBCs
RBCs
Organisms
1) What is the color of urine range? What does it usually correlate with?
2) Color can vary widely due to what?
3) True or false: Redness alone does not indicate a large amount of blood. Explain your answer.
1) Ranges from pale yellow (straw colored) to deep amber
Usually correlates to concentration of the urine
2) Food and drugs
3) True; 1mL of blood can discolor 1L of urine
Describe the 3 causes of red urine
Dark red urine: bleeding from kidney
Bright red urine: bleeding from lower urinary tract
Menstruation: no action if asymptomatic
Pyridium (phenazopyridine) and Azo can do what to urine?
Make it bright orange or red
True or false: Normal urine should be clear and not cloudy
True
What are some causes for turbidity of a urine sample? Specify which is most common
Pus
Bacteria (most common)
RBCs
Fatty food (sometimes)
Sperm
Refrigerated urine
What type of data is urine odor and what should you do with it?
Subjective, chart; will not be included on the report
True or false: urine odor is debatably useful
True
1) What does glycosuria smell like?
2) What does bacteria in urine smell like?
3) What smell in urine would indicate a fistula?
1) Sweet, acetone-smelling
2) Foul smelling
3) Fecal smelling
List the 10 parts to a dipstick test
1) pH
2) Specific gravity
3) Protein
4) Leukocyte esterase
5) Nitrite
6) Glucose
7) Ketones
8) Bilirubin
9) Urobilinogen
10) Blood
1) What is the reference range for urine pH?
2) Compare urine pH to blood pH
3) What is a major regulator of acid-base balance?
1) 4.6 – 8.0 (average 7.0)
2) Normally slightly acidic compared to blood pH
3) Kidneys
There’s a wide variety of causes for abnormal urine pH; list some
Acid-based disturbances
Renal dysfunction
Diet
Medications
Bacteria
1) What is the reference range for urine specific gravity?
2) What does it measure?
1) 1.005 – 1.030
2) Concentration of urine; higher specific gravity = more concentrated urine
Is specific gravity the same as osmolality?
Not the same as osmolality, but correlates to it
1) Osmolality determined by ______________ of particles
2) Specific gravity is determined by ____________ and __________ of particles
1) number
2) number and size
1) How is specific gravity determined?
2) What can throw off the correlation between specific gravity and osmolality?
3) What affect would the correlation being thrown off have?
1) Weight of the solution / weight of same volume of distilled water
2) Larger particles like glucose or radiocontrast media
3) Lead to impression of concentrated urine when it is dilute
What may specific gravity need to be followed up with?
Urine osmolality if needed
Name 4 things specific gravity may be lower due to
Overhydration
Diabetes insipidus
Nephropathy
Acute tubular necrosis
Urine concentration has important diagnostic value; explain
Kidney disease diminishes the concentrating power of the kidney
1) Antidiuretic hormone (vasopressin) does what?
2) What does increased ADH lead to?
3) What abt decreased ADH?
1) Increases water reabsorption by decreasing water excretion
2) Increased water reabsorption > decreased water in urine > high specific gravity
-High ADH = higher specific gravity (more concentrated urine)
3) Lower specific gravity (less concentrated urine)
1) What are potential protein dipstick values? What is the reference value?
2) Presence of protein in urine is an important potential indicator of _______________, but is not diagnostic
1) Dipstick values: trace, 1+, 2+, 3+ Reference value: negative
2) renal disease
1) Regarding protein, the reagent strip is sensitive to what?
2) What is proteinuria mostly synonymous with?
3) What is the most abundant plasma protein?
4) What would a strip not detect?
1) Albumin
2) “Albuminuria”
3) Albumin
4) Low or moderate albuminuria
1) Concentration of urine can affect the result on what other test?
2) ______________ media can cause false positive for protein for about ________ days
1) Protein test
2) Radiocontrast ; 3
1) Sulfosalicylic acid test (SSA) detects what?
2) If dipstick is negative for albumin but SSA is positive, this suggests what?
1) Detects all urine proteins
2) Non-albumin proteinuria
1) Urine protein is a sensitive indicator of ___________ or ___________ renal dysfunction
2) What can lead to protein leaking from the “spaces”? Give an example of when this may happen
3) When is protein not being reabsorbed?
1) glomerular or tubular
2) Inflammation of the membrane, as with glomerulonephritis
3) In tubular disease
Leukocyte Esterase:
1) What is the reference value?
2) What releases it? What does it indicate?
3) What would a positive test support?
1) Negative
2) Released by lysed neutrophils and macrophages; indicates presence of increased WBCs
3) Diagnosis of UTI
Leukocyte Esterase:
1) What can result in a false positive?
2) What 3 things can result in false negative?
1) Contaminated specimen
2) Proteinuria, glycosuria, or highly concentrated urine
Nitrite:
1) What is the reference value?
2) Many (not all) bacteria produce an enzyme, nitrate reductase. What does this do?
3) Positive nitrite result on UA suggests what? What usually causes this?
1) Negative
2) Reduces urinary nitrates to nitrites
3) Nitrate reducing bacteria; usually gram-negative rods
True or false: Negative nitrite doesn’t rule out UTI. Explain.
True; might be due to presence of non-/low-nitrate reductase bacteria
1) When should you send a urine culture?
2) In what specific patients?
1) If a pt has a UTI
2) Only if PG, geriatric, pediatric, DM, fever, immunocompromised, male, recurrent infection, recent abx use (30d)
What two things does a urine culture tell you?
Tells you type of bacteria
AND
Which antibiotics will kill that bacteria
Glucose:
1) What is the reference value?
2) True or false: Different strips will have different ranges for the glucose result
3) What does a positive result indicate?
1) Negative
2) True
3) Uncontrolled DM or newly dx DM
1) Glucose spill over begins at _________mg/dL
2) What can cause spill over at lower glucose levels, even within normal serum glucose range?
1) 180mg/dL
2) Kidney disease
Ketones:
1) What is the reference value?
2) What are they the product of?
3) What do they indicate?
4) Give 3 examples of ketones
1) Negative
2) Fatty acid catabolism
3) Utilization of fats instead of carbohydrates
4) Acetone, acetoacetic acid, beta-hydroxybutyric acid
There are various causes for increased ketones; name some
1) Uncontrolled diabetes mellitus
2) Alcoholism
3) Fasting
4) Starvation
5) High protein diet
6) Certain pediatric illnesses
Diabetic ketoacidosis (DKA):
1) Is it an emergency? Why/ why not?
2) What is it?
1) Medical emergency: may result in coma or death
2) Metabolic acidosis in type 1 DM patients caused by too much ketone production in the face of insulin deficit
Diabetic ketoacidosis (DKA):
1) Metabolic acidosis in type 1 DM patients is caused by what?
2) Describe what this leads to
1) Too much ketone production in the face of insulin deficit
2) Leads to increased glucagon which increases glucose release from liver (which was already too high)
-Glucose spills over into urine. Takes water, sodium, and potassium with it.
-Ketones released as body switches to fatty acids for energy
-Without insulin (and therefore glucose) body’s demand for energy increases ketone production beyond buffering capacity. Blood pH decreases too much.
Describe the chain reaction that happens during DKA and what it ultimately does to blood pH
1) Metabolic acidosis in type 1 DM patients caused by too much ketone production in the face of insulin deficit
2) Leads to increased glucagon which increases glucose release from liver (which was already too high)
3) Glucose spills over into urine. Takes water, sodium, and potassium with it.
4) Ketones released as body switches to fatty acids for energy
5) Without insulin (and therefore glucose) body’s demand for energy increases ketone production beyond buffering capacity.
6) Blood pH decreases too much.
UA showing positive for _____________ and _____________ supports diagnosis of DKA
glucose and ketones
Bilirubin:
1) Is it normally present in urine?
2) What is it a major constituent of? What happens if excretion is inhibited?
1) No (reference value = negative)
2) Bile; will turn into conjugated bilirubin which is water soluble and excreted into urine
Urine bilirubin suggest one of what two things?
Gallstones or disease of bilirubin metabolism
Urobilinogen:
1) Is it normally present in urine?
2) What produces it?
3) Describe its path
1) Yes; reference value is positive
2) Produced by breakdown of bilirubin in intestines.
3) Reabsorbed and excreted in urine.
1) Increased urobilinogen suggests one of what two things?
2) Decreased urobilinogen suggests what? What Dx does this support?
1) Liver disease or hemolysis
2) Decreased bilirubin reaching the intestines; gallstones.
Blood/RBCs:
1) What is the reference value?
2) Define “gross/frank hematuria”
3) Define “microscopic/microhematuria”
4) Define dipstick hematuria
5) If sent for urinalysis, report will indicate what?
1) Negative
2) Visible with naked eye
3) Visible only under microscope
4) Color change indicating RBCs in urine
5) Number of RBCs
What is blood in urine the #1 indication of?
Bladder cancer (which is mostly seen in elderly)
1) There’s a wide variety of causes for blood in urine; list some.
2) What should you do if benign transient cause is suspected?
1) Acute tubular necrosis, trauma, cancer, menstruation, recent sexual intercourse, exercise induced, UTI
2) Repeat UA later
What should you do if there’s blood in your pt’s urine and you don’t know why? (i.e. not UTI or menstruation)
Send to Urology for workup
Microscopic Exam: Crystals
1) What do crystals suggests?
2) What are some types?
3) What should you provide? What would you do next?
4) What’s the reference value?
1) Presence of renal calculi
2) Uric acid, calcium oxalate, calcium phosphate, cystine
3) Provide strainer to catch stone, diet or rx based on stone type
4) Negative
Casts:
1) What are they?
2) What shape are they?
3) Why should cast examination should be performed on fresh specimens?
1) Clumps of cells that have been concentrated in the distal and collecting tubules
2) Take on the shape of tubule
3) Will break up if allowed to sit in urine
Casts:
1) What is the reference value?
2) What should you do if positive?
1) Negative
2) Send to nephro or urology
1) What are hyaline casts?
2) What are cellular casts?
1) Clumps of protein, indicate proteinuria
2) Degenerated cells. Many types
Cellular cast types:
1) What are cellular casts?
2) What are granular casts?
3) What are waxy casts?
4) What are fatty casts and what may they be associated with?
1) Degenerated cells. Many types
2) Disintegration of cells into granular particles
3) Further disintegration due to diminished urine flow through tubule (more time to degenerate)
4) Fatty deposits with protein; long bone fractures.
WBC casts: pyelonephritis
RBC casts: glomerulonephritis
1) Should any other cells be found in urine?
2) What cells’ presence suggests UTI?
3) What cells indicate nephrotic syndrome?
4) What cells indicate contamination?
1) No; reference value is negative
2) Presence of bacteria, especially gram-negative rods, suggests UTI
3) Renal epithelial cells
4) Squamous cells
Summary:
1) What would a LOW specific gravity indicate?
2) What does pH tell you?
3) What would protein indicate?
4) What indicates liver disease?
1) Kidney disease
2) Acid-base balance
3) Kidney disease
4) Bilirubin and (urobilinogen)
Summary:
1) What is always indicative of a UTI?
2) What is likely a UTI?
3) What two things are debatable for a UTI? Should you treat them for UTI if positive?
1) Leukocyte esterase and nitrite: UTI
2) Leukocyte without nitrite: likely UTI
3) Nitrite without leukocyte
-&Bacteria without leukocyte
-Do not treat (unless pregnant)
Summary:
1) What is indicative of DKA?
2) What is indicative of DM?
3) What should you do if RBCs/ blood are positive? (without UTI, menstruation, or other valid cause)
1) Glucose and ketones
2) Glucose
3) Send to Urology (if all else negative)
