Urinalysis exam 2 Flashcards
How does the pH of urine relate to its hydrogen ion concentration?
There is an inversely proportional relationship between the number of hydrogen ions in solution and the numerical value for pH
Ketone bodies in the urine are suggestive of elevated ________ metabolism.
fat
What causes myoglobinuria?
muscle disorder, muscle trauma, severe crush injury
*extensive muscle injury
What is the general purpose of test strip screening?
Provide info as to whether or not pathological concentrations of substances are present in the urine, and if further clinical testing is necessary in order to confirm a diagnosis suggested by the findings.
What color is a (+) positive nitrite on the dipstick?
pink
What substance is most likely to be present in urine that could have a false (=) negative reaction on the dipstick for glucose?
ascorbic acid(vitamin C)
What is the SSA used for?
*confirm protein in urine
what test is used for detecting reducing sugars in the urine? What would be expected in the microscopic examination?
- clinitest
* nothing
What two dipstick reactions are usually (+) positive in pyelonephritits and cystitis?
- nitrites
* leukocytes
Name several conditions that could be indicated by an elevated urinary urobilinogen.
liver disease (ie: hepatitis, cirrhosis) or hemolytic states (ie: pernicious anemia)
Name several conditions that can cause hemoglobinuria.
intravascular hemolysis conditions (ie: transfusion rxn), extensive burns, strenuous exercise, injury, hemolytic anemia, PNH-paroxysmal nocuturnal hemoglobinuria
What is specificity (as related to dipstick reactions)?
Ability of each test zone to react to a certain substance and being tested and to no other.
The test pad for ketone bodies detects_________?
acetoacetic acid
What is the principal of the dipstick method for protein?
uses protein error of indicators principle - tetrabromphenol blue-buffered @ constant pH 3.0.
Without proteins: yellow
In the presence of proteins: H+ are released by the indicator dye & cause color change (yellow-green to blue-green)
What unusual urinary protein is associated with multiple myeloma?
Bence-Jones
What sugar (especially in infants) is most likely indicated by a (=) negative dipstick reaction for glucose but a (+) clinitest?
galactose
What specimen is used to detect orthostatic proteinuria? When would you suspect this condition?
First morning specimen followed 2 hrs later after being erect/upright for that time; suspect in young children &
adolescence.
What is the active ingredient in Ehrlichs’s reagent?
paradimethylaminobenzaldehyde
What is the reagent used to detect bilirubin in the icotest?
2,4-dichlorobenzene diazonium tetrachlorozincate
The reagent strip for hemoglobin detects _____,______ and _________.
free hemoglobin, myoglobin, intact RBC’s
What is the action of the enzyme peroxidase?
*sudoperoxidase activity catalyzes oxidation reaction of 3,3’,5,5’-tetramethylbenzidine by oxygen released from peroxide
Why is there normally no glucose in the urine?
All filtered glucose is reabsorbed in distal convoluted tubules
What is the advantage of using phase contrast micorscopy in the examination of urinary sediment? How does this elate to the refractive index?
- unstained components and casts
* refractive index is similar to urine
What is the use of the polarizing microscope in urine microscopics?
Detection of birefringent substances (lipids & crystals)
Cells are recorded as number per _____ power field.
High (40X)
How many fields should be examined in a microscope exam?
10
What is the most common type of WBC found in urinary sediment?
neutrophils
Casts in urine are usually accompanied by a (+) test for ______?
protein
Casts containing cells indicate problems in what part of the urinary tract?
kidneys
Where are the transitional epithelial cells found?
Renal pelvis & calyces, ureters, bladder, 2/3 of male urethra
Amorphous phosphates are found in urine of what pH?
alkaline
What disease is indicated when tyrosine and leucine are found in the urine?
liver disease
Nephrotic syndorme is charactized by______and_______.
proteinuria & lipiduria
casts which have at least two distinct components are called ________ casts.
mixed
Casts shoud be reported as the number per _____power field.
low (10X)
Which WBC is most likely to be found in a transplant rejection?
lymphocytes
In what specific portions of the nephron are casts formed?
In the lumen of the distal convoluted tubules and collecting ducts.
In what type of diseases (in general) are RBC casts found?
where the basement membrane of glomerulus is damaged - intrinsic renal disease.
What specific type of epithelial cells are found in epithelial cell casts?
renal tubular
Glitter cells are associated with urine of ______ specific gravity.
low
What type of epithelial cells are indicative of vaginal contamination?
squamous epi
Calcium oxalate crystals are normally found in ______ pH urine.
acidic
What condition is indicated by large numbers of uric acid crystals?
gout
Candida Albicans (a yeast) is often found in the urine of patients with what?
diabetes mellitus
If flat, hexagonal, colorless crystals are found in urine, what constituent is suggested? What should the technologist do prior to reporting out these abnormal crystals?
Cystine; chemical confirmation for cystine
How can RBC and yeast be differentiated
add acetic acid & RBC’s will lyse
what is the appearance of waxy casts?
high refractive index, edges defined, sharp, blunt or uneven ends, cracks or fissures, irregular shapes
Name several organisms whose urinary presence indicates contamination
yeast, trichomonas, parasites, squamous
the order for the aging process of casts is ______, _______,______ and _________.
- cellular
- coarse granular
- fine granular
- waxy
What is the term for the presence of elevated numbers of casts in urine?
cylindruria
How can a precipitate of amorphous phosphate be removed? What about amorphous urates?
- Phosphates: dissolved in acetic acid.
* Urates: alkali or heated to 60C.
What would be the appearance of RBC in hypertonic urine?
crenated
Can the mulistix detect a negative bilirubin?
no(lowest is 0.2)
How would you interpret a (=) nitrate but a (+) bacteria?
does not reduce nitrate to nitrite; no nitrates in the diet; urine may have been collected prematurely
what happens if you dip the reagent strip too much?
- the test on the pads could run together
* leeching or runover of reagents
What type of casts may be found in the urine of a normal pH?
hylaine in low #’s
What are shadow cells?
These are cells that have lost their hemoglobin.
What is the significance of the shape and size of a cast?
identifies what type it is
Urine for testing should always be at _____ temp.
room
How does the Watson-Schwarz test differentiatie between urobilinogen and prophobilinogen?
Solubility; urobilinogen soluble in chloroform & butanol Porphobilinogen soluble in aqueous layer.
What is the principle of the automated instruments for a dipstick reading?
reflectance photometry
Why do we use the refractometer for specific gravity rather than the dipstick?
It detects both ionic solutes (radiographic dyes, protein, glucose, urea) and non-ionic solutes. Dipstick is ionic only.
Glucose in the urine is referred to as ______ or ________.
glycosuria & glucosuria
The two different forms of blood in the urine are described as _____ and ______.
hematuria and hemoglobinuria
What reagent is used to differentiate urinary hemoglobin and myoglobin?
ammonium sulfate; myoglobin does not precipitate out/hemoglobin does
What is the normal range for urinary urobliliongen?
0.1 to 1.0 mg/dL
Which test is the most sensitive for bilirubin?
ictotest
what is ketonuria?
excess ketones in urine, body using fat for energy
Glucose reagent strip reaction
Glucose + O2 —> gluconic acid + H2O2
glucose and oxidase catalysts
Potassium iodide dipstick reagent reaction
H2O2 + Chromogen —> oxidized chromogen + H2O
Peroxidase is catalyst
Pt vomiting; cant keep food in – expect to see
ketones
Possibilities for blood in urine
trauma, tumors, stones, glomerulonephritis, exercise, smoking, pylonephritis, myoglobin
If blood on dipstick you want to differentiate b/w hemoglobin and myoglobin. why
ammonium sulfate
