Exam II Study Guide Flashcards
How does the pH of urine relate to its hydrogen ion concentration?
inverse relationship
increase H+, decrease pH
decrease H+, increase pH
Ketone bodies in the urine are suggestive of what?
elevated COH metabolism
What causes myoglobinuria?
rhabdomyolysis, muscle destruction
What color is positive nitrite on dipstick
pink
What substance is most likely to be present in urine that could cause a false negative reaction on dipstick for glucose?
ascorbic acid, vitamin D
What is SSA used for?
confirmatory test for proteins
What test is used for detecting reducing sugars in the urine? What would be expected in microscopic exam?
Clinitest
nothing
What two dipstick reactions are usually positive in pyelonephritis?
leukocytes and nitrite
Conditions that could be indicated by elevated urinary urobilinogen
hepatitis cirrhosis liver disease hemolytic anemia PA
Conditions that can cause hemoglobinuria
extensive burns intravascular hemolysis incompatible transfusions PNH-paroxysmal nocturnal hemoglobinuria infections; malaria, syphillis
What is specificity in relation to the dipstick?
each zone should react specifically to the substance being tested and no other
What does the test pad for ketones detect
acetoacetic acid
Principle of the dipstick method for protein
“protein error of indicators” tetrabromphenol blue buffered at a constant pH of 3 w/o proteins is yellow, but in the presence of proteins, H+ is released by indicator dye causing color to change ranging from ylw-gr to bl-gr
What unusual urinary protein is associated with Multiple Myeloma
Bence Jones protein
What sugar, especially in infants, is most likely indicated by a neg dipstick reaction for glucose but a pos Clinitest
galactose
WHat specimen is used to detect orthostatic proteinuria? When would you suspect this condition?
1st morning specimen (=) and specimen after patient has been erect for a few hours (+).
If protein is excreted sitting up but not laying down
seen in kids and adolescents
What is the active ingredient in Ehrlich’s reagent?
paramethylamino benzaldehyde
What reagent is used to detect bilirubin in the Ictotest?
2,4 - dichlorobenzene diazonium tetrachlorozincate
Hemoglobin pad on reagent strip detects
hemoglobin
myoglobin
intact rbcs
What is the action of the enzyme peroxidase?
to catalyze the oxidation of chromogen (3,3’,5,5’ - tetramethylbenzidine) by the O2 released from peroxidase on reagent pad to produce color change from yellow to green; sudoperoxidase acitivity
Why is there normally no glucose in urine?
usually reabsorbed back into the blood through the renal convoluted tubules
Advantage of using phase contrast microscopy in exam of urinary sedimentation? Relation to refractive index?
allows you to see unstained cellular components and casts
refractive index is similar to urine, enables you to see difficult to view formed elements
What is the use of polarizing microscope in urince microscopics?
detects sediment that is birefringent (anisotropic) and confirm presence of fat and cholesterol crystals
How are cells recorded
number per High (40x) power field
How many fields should be examined?
lpf/hpf 10 fields; dependent on what the examiner is looking for
What is the most common type of WBC found in urinary sediment?
neutrophils
Whats usually pos when casts are present?
protein
Casts containing cells indicate problems in what part of the urinary tract
kidney
Where are transitional epi cells found
lining of renal calyces, renal pelvis, ureters and and bladder. urethra in males
Amorphous phosphates are found in what kind of urine?
alkaline
What disease is indicated when tyrosine and leucine crystals are found in urine
severe liver disease; overflow of aminoaciduria
What is characterized by lipiduria and proteinuria
Nephrotic syndrome
Casts which have at least two distinct compnents
mixed casts
How should casts be reported
lpf 10x
Which WBC is most likely to be found in a transplant rejection
lymphocyte
In what specific portion of the nephron are casts formed
distal convoluted tubule and collecting ducts
Types of diseases RBC cast are found
intrinsic renal disease
basement membrane where glomerulous is damages
Specific epi cells found in epi casts
renal tubular epi cells
Glitter cells seen in urines with
low SG
Epi cells indicative of vaginal contamination
squamous
Calcium oxalate crystals are seen in
acidic urine
low pH
Condition indicative by large numbers of uric acid crystals
gout
increase purine metabolism, such as treatment with cytotoxic drugs sued in leukemia
Candida albicans often seen in urine of pts with
diabetes mellitus
If flat, hexagonal, colorless crystals are found in urine, what constituent is suggested? What should be done prior to reporting?
Cystine
chemical confirmatory testing
How can rbc and yest be differentiated
2% acetic acid; lyse rbcs
toludine blue; stain S-M color reveal nuclear details
What is the appearance of waxy casts?
sharp, blunt uneven ends
cracks or fissures from lateral margins and along axes
high refractive index
homogenous
Organisms that indicate contamination
parasites
Trich
sperm
yeast
Order of aging process of casts
cellular, coarse granular, fine granular, waxy
Presence of elevated numbers of casts in urine
cylinduria
How can precipitate of amorphous phosphate (alkaline) crystals be removed
dissolve in diluted acetic acid
How can precipitate or amorphous urate (acidic) crystals be removed
dissolve in alkali or heat to 60C using warm water
What would the appearance of rbc in hypertonic urine be
crenated
Can the multistix detect a neg urobilinogen
neg is there is none in urine, but cannot detect a complete absence
How would you determine a neg nitrite but a pos bacteria
urine not in bladder long enough, nitrate to nitrite reductions hasnt occured
bacteria pop is too high and nitrite has been further reduced to nitrogen
no nitrite in diet
leeching or runover of reagents
What type of casts may be found in the urine of normal pH
hyaline
What are shadow cells
rbc with nohgb
What is the significance of the shape and size of a cast
variable; helps in ID
cast type can distinguish kidney disease from lower urinary tract disease
Urine for testing should always be
room temp
Why use refractometer for SG instead of dipstick
dipstick detects ionic solutes only
refractometer detects ionic solutes and non ionic solutes
How does Watson-Schwartz test differentiate between urobilinogen and porphobilinogen
red+chloroform = uronilinogen
soluble in chloroform and butanol
red+butanol = porphobilinogen
soluble in aqueous layer
What is the principle of the automated instruments for dipstick reading
reflectence
Glucose in urine is referred to as
glycosuria
glucosuria
Two different forms of blood in the urine are known as
hematuria
hemoglobinuria
What reagent is used to differentiate urinary hgb and myoglobin
ammonium sulfate
precipitates hgb
What is the normal range for urinary urobilinogen
0.1-1 mg%
Which test is most sensitive for bulirubin
Ictotest
What is ketonuria
excessive amounts of ketone bodies in urine
