Urinalysis

Question 1

What changes happen to urine at room temperature?

Answer 1

increased pH, decreased glucose, decreased ketones, decreased bilirubin, decreased urobilinogen, increased bacteria, increased turbidity, disintegration of red blood cells and casts, changes color

Question 2

clear urine

Answer 2

like water; easily read newspring

Question 3

hazy

Answer 3

blurry but lines are still visible

Question 4

cloudy

Answer 4

lines are barely visible; cannot read newsprint

Question 5

turbid

Answer 5

cannot see through it; often have particulates

Question 6

Significance of foam in urine

Answer 6

white foam: protein is present

yellow foam: bilirubin is present

Question 7

glucose reagent strips

Answer 7

normal result: negative

abnormal: diabetes mellitus, impaired tubular resorption, and inborn errors of metabolism

Question 8

pre-renal glycosuria

Answer 8

plasma glucose level exceeds renal threshold (diabetes mellitus)

Question 9

renal glycosuria

Answer 9

plasma glucose level below renal threshold, but tubules cannot reabsorb glucose back into bloodstream

Question 10

glucose reagent strip specificity- false negative/postive causes

Answer 10

reacts only with glucose. False positive: strong oxidizing agents, peroxides
false negatives: ascorbic acid, high ketone levels, improperly stored urine

Question 11

clinitest

Answer 11

copper reduction test, detects all reducing sugars and reacts with glucose, galactose, lactose, fructose, ascorbic acid, homogenistic acid but not sucrose

Question 12

what level of glucose is required to detect on clinitest and dipstick?

Answer 12

clinitest: 250 mg/dl
dipstick: 100 mg/dl

Question 13

bilirubin dipstick

Answer 13

only find conjugated bilirubin in urine. Normal result is negative. Abnormal: seen in liver disease, hepatic jaundice obstruction, obstructive jaundice.

Question 14

Reasons for false negative for bilirubin

Answer 14

ascorbic acid inhibits, high urine nitrites inhibit, low bilirubin concentration, improper specimen handling (protect from light)

Question 15

reasons for false positive bilirubin

Answer 15

urine color interference, drug induced color changes, perform ictotest to confirm presence of bilirubin

Question 16

ketones dipstick

Answer 16

products of incomplete fat metabolism. Normal: negative. abnormal: inability to utilize carbs, DM, inadequate intake of carbs, excessive loss of carbs. Fruity odor from acetone

Question 17

reasons for ketone false negatives

Answer 17

improper storage: volatilization, bacterial breakdown

Question 18

reasons for ketone false positive

Answer 18

compounds containing free-sulfhydryl groups, highly pigmented urines

Question 19

specific gravity dipstick

Answer 19

concentration of the urine. Normal: 1.002 to 1.035

abnormal: increased SG means concentrated, decreased SG means dilute

Question 20

isothenuira

Answer 20

SG fixed at 1.010, renal tubules lost absorption and secreting capability

Question 21

hyperthenuria

Answer 21

increased SG, concentratied urine, hypertonic

Question 22

hyposthenuria

Answer 22

decreased SG, dilute urine, hypotonic

Question 23

blood dipstick test

Answer 23

normal: negative
abnormal: kidney stones, glomerulonephritis, strenuous exercise, hemolytic anemia, transfusion reactions. Can be intact or hemolyzed RBC

Question 24

Blood false positive reasons

Answer 24

menstrual contamination, microbial peroxides, oxidizing agents (bleach)

Question 25

blood false negative reasons

Answer 25

ascorbic acid, high levels of protein, high nitrite reduces strip reactivity

Question 26

pH dipstick

Answer 26

normal: 4.5-8 acidic: acidosis, high protein diet, starvation, dehydration or diarrhea alkaline: alkalosis, UTI, vegetarian diet, vomiting, or chronic renal failure

Question 27

what pH ranges are physiologically impossible?

Answer 27

<4.5, if >8.0 expect that urine not handled properly, old urine, or treatment induced

Question 28

protein dipstick

Answer 28

normal: negative transient: occurs w/ fever, exposure to heat or cold, emotional stress, pregnancy exercise pathological: membrane damage, disorders affecting tubular reabsorption

Question 29

What are the two renal causes of proteinuria?

Answer 29

glomerular damage and tubular dysfunction.

Question 30

Glomerular damage

Answer 30

most serious cause of proteinuria, and most common. glomerulonephritis and nephrotic syndrome (highest levels of protein)

Question 31

tubular dysfunciton

Answer 31

reabsorption capability decreased, toxin exposure, inherited disorder, Fanconi's syndrome: heave metal poisoning

Question 32

What is the sensitivity and specificity of protein dipstick?

Answer 32

sensitivity: about 10-25 mg/dl specificity: reacts with albumin

Question 33

reasons for protein false positive

Answer 33

highly buffered or alkaline urine, alkaline drugs, improper storage and handling, contamination of detergents

Question 34

reasons for protein false negative

Answer 34

dilute urine, presence of other proteins (uromodulin, globulins, myoglobin, free light chains, hemoglobin), exercise/transitory conditions

Question 35

urobilinogen dipstick

Answer 35

formed in intestine from bilirubin by bacteria. normal: .2-1.0 abnormal: hemolytic disease, liver disease cannot determine absence of UBG

Question 36

nitrites

Answer 36

some gram - bacteria reduce dietary nitrates to nitrites (UTI). normal: negative abnormal: UTI, cystitis, pyelonephritis

Question 37

nitrite false positive reasons

Answer 37

substances that mask reaction color, foods (beets), drugs, improper specimen storage/handling

Question 38

nitrite false negative reasosn

Answer 38

ascorbic acid, bacteria cannot reduce nitrates, bladder time not sufficient (need 4 hours), low nitrate levels, antibiotic inhibition of bacteria, further reduction to nitrites to nitrogen

Question 39

leukocytes

Answer 39

normal: negative abnormal: UTI, cystitis, pyelonephritis, urethritis

Question 40

leukocyte false positive reasons

Answer 40

substances that induce color mask, vaginal contamination,

Question 41

leukocyte false negative reasons

Answer 41

not waiting 2 minutes, lymphocytes present, increased glucose and protein, strong oxidizing agents, drugs

Question 42

leukocyte specificity

Answer 42

5-15 WBC/hpf

Question 43

ascorbic acid

Answer 43

interferes with reagent strip reaction.

Question 44

what does ascorbic acid cause false negatives for?

Answer 44

nitrite, blood, glucose, bilirubin

Question 45

What reagent strip reactions do oxidizing agents (bleach) affect?

Answer 45

glucose: false positive blood: false positive leukocytes: false negative