UA 2 Flashcards
(31 cards)
What accounts for false positives in Bilirubin UA?
pyridium
What accounts for false negatives in Bilirubin UA?
nitrites, light, ascorbic acid (light breaks down bilirubin)
How is urobilinogen derived?
Urobilinogen is derived from metabolism of conjugates bilirubin by intestinal flora
When would you have a positive test for urobilinogen?
positive urobilinogen is when there is so much bilirubin being produced but not getting out, ex: fecal obstruction or so many RBC being lysed, conjugated into LI, acted on by bacteria then reabsorbed ex: hemolytic anemia
What is a normal reference range for urobilinogen?
.2-1mg/dl
what causes increased urobilinogen (slide 55)
intravascular hemolysis (hemolytic anemia) or intestinal obstruction
What is most likely to result in a false negative urobilinogin UA dip?
antibiotics - (killing off bacteria in intestines). Urobilinogen is derived from metabolism of conjugated bilirubin by intestinal flora
What us the normal finding for nitrites in a UA dip?
Negative
What does a urine level increase of nitrites indicate?
UTI
What is the mechanism for increased nitrites with UTI?
many gram negative bacteria produce the enzyme nitrate reductase which reduced urinary nitrates to nitrites
ex: ecoli
What can give a false positive Nitrite UA
pyridium - pain
What can give a false negative?
Ascorbic acid (vitamin C), a low nitrite diet
What is a normal test result for UA dip leukocyte esterase
negative
what is a leukocyte esterase UA?
a screen to detect WBC in the urine
What is a positive leukocyte esterase indicative of?
indicate likelihood of urinary tract infection
what are 2 non-urinary causes of pyuria?
appendicitis and pancreatitis
What could result in false positives of leukocyte esterase?
vaginal secretions
what could result in false negative leukocyte esterase?
glucose, protein, increase SG
for microscopic exam, What is a quality of normal urine?
normal urine in sterile
for microscopic exam, Why is most bacteria in Urine sample gram negative?
due to the proximity of the G.I. tract
for microscopic exam, What could be a non-urinary tract source of bacteria in a urine sample?
contaminants from skin or genital tract
on microscopic exam, what would yeast look like in a urine sample?
budding, branching, - sugar i.e. diabetics and immunocompromised
on microscopic exam: what would squamous epithelial cells indicate?
contaminant from lower GU(big fried eggs, lower 1/3 of urethra due to contamination or inflammation)
on microscopic exam; what would transitional epithelial cells indicate?
line the urinary tract from renal pelvis to the proximal 2/3 of the urethra
