Urinalysis - Chemical Urinalysis by Reagent Strip

Question 1

What is the normal pH of a first morning specimen?

Answer 1

5-6

Question 2

What is the normal pH of a random urine specimen?

Answer 2

4.5-8

Question 3

What is the principle of a pH test?

Answer 3

double indicator system

Question 4

What is the significance of urine pH?

Answer 4

-acid-base balance
-management of urinary tract infections & renal calculi

Question 5

pH with a protein/meat diet

Answer 5

acid

Question 6

pH with a vegetarian diet

Answer 6

akaline

Question 7

What is the pH of a improperly preserved urine specimen?

Answer 7

9 or above

Question 8

What is the normal value for urine protein?

Answer 8

negative to trace

Question 9

What is the principle of a urine protein test?

Answer 9

protein error of indicator

Question 10

What is the significance of urine protein?

Answer 10

possible renal disease

Question 11

In a solution that does not contain protein, tetrabromphenol blue, buffered at a pH of 3, is what color?

Answer 11

yellow

Question 12

What protein is the urine protein test most sensitive to?

Answer 12

albumin

Question 13

What would protein results look like in orthostatic proteinuria?

Answer 13

-protein would be negative in the first morning sample
-protein would be positive after standing

Question 14

What is the normal range for glucose in a urine sample?

Answer 14

negative

Question 15

What is the principle of a urine glucose test?

Answer 15

glucose oxidase/peroxidase

Question 16

What is the significance of a positive glucose result?

Answer 16

possible diabetes mellitus

Question 17

What is the normal renal threshold for glucose?

Answer 17

160-180 mg/dL

Question 18

Is the glucose urine test specific for glucose?

Answer 18

yes

Question 19

What is the normal range for urine ketones?

Answer 19

negative

Question 20

What is the principle for the urine ketone test?

Answer 20

sodium nitroprusside reaction

Question 21

What is the significance of ketones in urine?

Answer 21

increased fat metabolism due to uncontrolled diabetes, vomiting, starvation, low carb diet, or strenuous exercise

Question 22

What is the ketone urine test most sensitive to?

Answer 22

acetoacetic acid

(less sensitive to acetone)

Question 23

Does the ketone urine test react with beta-hydroxybutyric acid?

Answer 23

no

Question 24

What is the normal range for blood in urine?

Answer 24

negative

Question 25

What is the principle of the urine blood test?

Answer 25

pseudoperoxidase activity of hemoglobin

Question 26

What is the significance of blood in urine?

Answer 26

-hematuria -hemoglobinuria -myoglobinuria

Question 27

What does the reagent strip for blood look like if it is positive due to hemoglobin or myoglobin?

Answer 27

uniform in color

Question 28

What does the reagent strip for blood look like if it is positive due to red blood cells?

Answer 28

speckled

Question 29

What is the normal range for bilirubin in urine?

Answer 29

negative

Question 30

What is the principle of the urine bilirubin test?

Answer 30

diazo reaction

Question 31

What is the significance of a positive urine bilirubin?

Answer 31

-liver disease -biliary obstruction

Question 32

What type of bilirubin is excreted in urine?

Answer 32

ONLY conjugated bilirubin

Question 33

What is the normal range for urine urobilinogen?

Answer 33

1 Ehrlich unit or 1 mg/dL

Question 34

What is the principle of the urine urobilinogen test?

Answer 34

Ehrlich aldehyde reaction OR diazo reaction

Question 35

What is the significance of an increased urine urobilinogen result?

Answer 35

-liver disease -hemolytic disorders

Question 36

Do urine reagent strips detect the absence of urobilinogen?

Answer 36

no, they only detect increases

Question 37

What is the normal range for urine nitrites?

Answer 37

negative

Question 38

What is the principle of the urine nitrite test?

Answer 38

Greiss reaction

Question 39

What is the significance of a positive urine nitrite?

Answer 39

UTI

Question 40

Why would a nitrite test be positive in cases of UTIs?

Answer 40

some bacteria reduce nitrates to nitrites

Question 41

Why is a first morning specimen ideal when testing for nitrites?

Answer 41

increased sensitivity when urine has been in the bladder for at least 4 hours

Question 42

What is the normal range for urine leukocyte esterase (LE)?

Answer 42

negative

Question 43

What is the principle of the leukocyte esterase test?

Answer 43

leukocyte esterase reaction

Question 44

What is the significance of a positive leukocyte esterase?

Answer 44

UTI

Question 45

What does the leukocyte esterase test detect?

Answer 45

intact and lysed granulocytes and monocytes, NOT lymphocytes

Question 46

What urine reagent strip tests can be used to screen urines for culture?

Answer 46

nitrite and leukocyte esterase tests

Question 47

What test on a urine reagent strip has the longest reaction time?

Answer 47

leukocyte esterase (2 minutes)

Question 48

What is the normal range for urine specific gravity?

Answer 48

Random specimen: 1.003-1.030

Question 49

What is the principle for a urine specific gravity test?

Answer 49

pKa change of polyelectrolyte

Question 50

What is the significance of specific gravity?

Answer 50

-indication of the kidney's concentrating ability & state of hydration

Question 51

Why is specific gravity increased in diabetes mellitus?

Answer 51

glucose

Question 52

Why is specific gravity decreased in diabetes insipidus?

Answer 52

decreased ADH

Question 53

What is reagent strip specific gravity NOT affected by?

Answer 53

-urea -glucose -radiographic contrast media -plasma expanders

Question 54

Possible effect of failure to test urine within 2 hours of collection or to preserve correctly

Answer 54

changes in chemical composition

Question 55

Possible effect of failure to bring refrigerated specimens to room temperature before testing

Answer 55

false-negative enzymatic reactions

Question 56

Possible effect of failure to mix specimen well

Answer 56

false-negative leukocyte, blood -WBCs and RBCs settle out

Question 57

Possible effect of failure to perform quality control

Answer 57

erroneous results

Question 58

When should quality control for reagent strips be done?

Answer 58

every 24 hours and when opening a new container

Question 59

Possible effect of failure to dip all test pads in urine

Answer 59

false-negative reactions

Question 60

Possible effect of prolonged dipping of the reagent strip into urine

Answer 60

false-negative reactions -reagents may leach from pads

Question 61

Possible effect of failure to remove excess urine from the reagent strip

Answer 61

runover of chemicals to adjacent pads, distortion of colors

Question 62

Possible effect of failure to read at recommended time

Answer 62

erroneous results

Question 63

Possible effect of highly pigmented urine

Answer 63

atypical colors, false-positive reactions -pigment masks true reactions (should test by alternate methods)

Question 64

Possible effect of failure to store test strips properly

Answer 64

erroneous results

Question 65

How should urine reagent strips be stored?

Answer 65

in capped original container at RT

Question 66

What would cause an increased pH on a reagent strip?

Answer 66

improperly preserved specimen

Question 67

What would cause a decreased pH on a reagent strip?

Answer 67

acid runover from protein square

Question 68

What would cause a false positive protein result on a reagent strip?

Answer 68

-highly buffered alkaline urine -prolonged dipping -contaminated container -increased specific gravity

Question 69

What would cause a false negative protein on a reagent strip?

Answer 69

proteins other than albumin

Question 70

What would cause a false positive glucose on a reagent strip?

Answer 70

contamination with peroxide or bleach

Question 71

What would cause a false negative glucose on a reagent strip?

Answer 71

-improperly preserved specimen -increased ascorbic acid -increased specific gravity -decreased temperature

Question 72

What would cause a false positive blood result on a reagent strip?

Answer 72

-menstruation -oxidizing agents -bacterial peroxidase

Question 73

What would cause a false negative blood result on a reagent strip?

Answer 73

-increased ascorbic acid -increased nitrite -increased specific gravity (crenated RBCs) -unmixed specimen