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Flashcards in Urine Dipstick Deck (120)
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1

What causes cloudy, red urine?

Red blood cells present (Hematuria)

2

What is normal urine pH?

Normal: slightly acidic (6.0) Random (4.4 - 8.0)

3

What causes the yellow color in urine?

Urochrome

4

What is the normal specific gravity of urine?

1.002 - 1.035

5

What is the highest concentration urine can reach?

1.040

6

What could cause a specific gravity above 1.040

Large amounts of glucose or radiographic dyes from x-ray procedures

7

What is the principle of protein detection on the dipstick?

The protein error of indicators - pH of strip 3.0 - dye changes color of strip

8

What protein does the the dipstick test detect?

Albumin

9

What causes false positives on the protein test?

Highly alkaline urine - highly pigmented urine - quaternary ammonium compounds, detergents, antiseptics, chlorhexadine

10

What causes false negatives on the protein test?

High salt

11

What is the clinical significance of the protein test?

Detects proteinuria - best single indicator of renal disease - can be caused by strenuous exercise

12

What causes false postives on the pH test?

No known causes

13

What causes false negatives on the pH test?

No known causes

14

What is the clinical clinical significance of the pH?

Alkaline urine can indicate "old" urine - sometimes seen after eating (this is in response to HCl secretion)

15

What is the principle of pH detection on the dipstick?

2 indicators, methyl red (red/orange -> yellow) and bromthylmol blue (green -> blue) - 2 indicators provide a wide spectrum of color changes

16

What is the principle of glucose detection on the dipstick?

Glucose oxidase method (double sequential enzyme) - glucose oxidase catalyzes rxn with glucose + O2 > gluconic acid and H2O2 - H2O2 catalyzes rxn between with chromogen to form oxidized colored compound - direct proportion to glucose concentration

17

What causes a false positive on the glucose test?

Bleach

18

What causes a false negative on the glucose test?

Vitamin C (newer strips are more resistant) -

19

What could Bence Jones proteins indicate?

Multiple myleoma (plasma cell myleoma)

20

what is the term for glucose in the urine?

Glycosuria

21

What is the renal threshold for glucose?

160 to 180 mg/dL

22

What effect does epinephrine have on urine glucose levels?

Inhibits the effect of insulin - seen with stress, cerebral trauma, and myocardial infarction

23

What hormonal disorders cause glycosuria?

Pancreatitis, pancreatic cancer, acromegaly, Cushing's syndrome, hperthydoidism, pheochromocytoma

24

What are the causes of renal glycosuria?

Tubular reabsorption disorder, end-stage renal disease, cystinosis, Fanconi syndrome, temporary lowering of renal threshold in pregnancy

25

What chromogens are used in the glucose test?

KI (green to brown - Multistix) and tetramethylbenzidine (yellow to green - Chemstrip)

26

What causes false positives in the glucose test?

H2O2 and oxidizing detergents like bleach

27

What are the three intermediate products of fat metabolism?

Acetone (2%), Acetoacetic acid (20%), and β-hydroxybutyrate (78%)

28

What causes ketones to appear in urine?

Body stores of fat are metabolized to supply energy

29

What are the primary causes of keonuria?

Diabetes mellitus, vomiting (loss of carbohydrates), starvation, malabsorption, dieting

30

What is diabetic ketoacidosis?

Increased accumulation of ketones in the blood due to diabetes - can lead to electrolyte imbalance, dehydration, and diabetic coma

31

What are some causes of ketonuria that aren't related to diabetes?

Inadequate intake/ absorption of carbohydrates, vomiting, weight loss, eating disorders, frequent strenuous exercise

32

Why should a diabetic monitor their ketonuria?

Keturnia is a sign of insulin deficiency and can be used to help monitor diabetes

33

What is the primary reagent used in the ketone test?

Sodium nitroprusside (nitroferricyanide)

34

What does the ketone test detect?

Acetoacetic acid - assumes the presence of acetone and
β-hydroxybutyrate

35

What is the principle reaction of the ketone test?

Sodium nitroprusside + acetoacetic acid (alkaline) = purple color

36

What could cause false positive results in the ketone test?

Highly pigmented urine, levodopa in high doses, medications contain sulfhydryl groups, improperly timed readings

37

What could cause false positive results in the ketone test?

Improperly preserved specimens (bacteria break down acetoacetic acid by bacteria)

38

What causes clear red urine?

Hemoglobinuria, product of red blood cell destruction

39

How much blood in the urine is considered clinically significant?

Any amount of blood greater than 5 red blood cells

40

What test is most accurate for determining the presence of hemoglobin in urine?

Chemical test

41

What method can be used to differentiate between hematuria and hemoglobinuria?

Microscopic examination

42

What are some causes of hematuria?

Renal calculi, glomerular disease, tumors, trauma, pyelonephritis, exposure to toxic chemicals, anticoaglulants

43

What causes clear red urine?

Hemoglobinuria

44

What are some causes of hemoglobinuria?

Transfusion reactions, hemolytic anemias, severe burns, infections/malaria, strenuous excercise/RBC trauma, brown recluse spider bites

45

The lysis of red blood cells in dilute, alkiline urine can cause what?

Hemoglobinuria

46

What is hemosiderin?

Yellow brown granules in urine sediment

47

What is the cause of clear red/brown urine?

Myoglobinuria

48

What is the cause of myoglobinuria?

Rhabdomyolysis (muscle destruction)

49

What are some causes of rhabdomyolysis?

Muscular trauma/crush syndromes, prolonged coma, convulsions, muscle-wasting disease, alcoholism, drug abuse, extensive exertion, statins

50

What is the mechanism of the blood test reagent?

H2O2 reacts with the heme component of blood which produces O2 > O2 + tetramethylbenzidine (chromogen) = color change

51

What color changes are indicated on the blood test pad?

Free hemoglobin shows uniform color - intact RBCs show a speckled pattern

52

What could cause a false positive on the blood test?

Menstrual contamination, strong oxidizing agents, bacterial peroxidases

53

What could cause a false negative on the blood test?

Vitamin C (>25 mg/dL), high SG/crenated cells, formalin, catopril, high concentrations of nitrite, unmixed specimens

54

Is conjugated bilirubin water soluble?

Yes

55

Is unconjugated bilirubin water soluble?

No (conjugated with glucuronic acid)

56

What is the clinical significance of bilirubin?

Liver damage ( hepatitis and cirrhosis) - hemolytic anemeas

57

What is the principle of the urobilinogen reaction?

Diazo reaction (Chemstrip), white to pink - dimethlyaminonbinzaldehyde + urobilinogen = peach to pink color (Ehrlich's reaction - Multistix)

58

What could cause a false positive in the urobilinogen test?

Urine pigments, phenazopyridine, drugs like indican and iodine

59

What could cause a false negative in the urobilinogen test?

Old specimens (biliverdin does not react), Vitamin C (>25 mg/dL), nitrite

60

What is the ictotest confirmatory for?

Bilirubin

61

What does a +++ bilirubin and normal urobilinogen test indicate?

Bile duct obstruction

62

What does a + or - bilirubin and ++ urobilinogen test indicate?

Liver damage

63

What does a negative bilirubin and +++ urobilinogen test indicate?

Hemolytic disease

64

What is the clinical significance of the nitrite test?

Bacteria (UTI)

65

What is the reaction principle for the nitrite test?

Nitrite + amine reagent = diazo compound > diazo compound + 3-hydroxy-1,2,3,4 tetrahydrobenz-(h)-quinolin = pink color

66

What could cause a false positive on the nitrite test?

Old specimens, highly pigmented urine

67

What could cause a false negative on the nitrite test?

Nonreductase containing bacteria, insufficient contact time between between bacteria and urinary NO3, lack of urinary NO3, large quantities of bacteria converting N02 to N2, presence of antibiotics, high concentrations of vitamin C, high SG

68

When should you repeat a nitrite test?

When negative results are obtained in the presence of clinical symptoms, even if symptoms are vague

69

What is the clinical significance of the leukocyte esterase test?

Indicates WBCs in the urine which like corresponds to a bacterial infection

70

Does the leukocyte esterase detect granulocytes or lymphocytes?

Granulocytes

71

What is the reaction principle of the leukocyte esterase test?

Leukocyte esterase splits ester to form pyrrole compound > pyrrole compound + diazo reagent = purple color

72

What could cause a false positive on the leukocyte esterase test?

Strong oxidizing agents, formalin, highly pigmented urine (nitrofurantoin)

73

What could cause a false negative on the leukocyte esterase test?

High conc. of protein, glucose, oxalic acid, Vitamin C - Crenation from high SG - inaccurate timing (must have 2 minutes) - presence of antibiotics (gentamicin, cephalosporins, tetracyclines)

74

What is the reaction principle of specific gravity?

pKa change of polyelectrolyte

75

What reagent is used for the specific gravity test?

Bromthymol blue

76

Why is the specific gravity test more accurate than the refractometer?

High MW compound, glucose, plasma expanders, and radiographic dye do not influence the test

77

What could cause a decreased reading of the specific gravity?

A pH of 6.5 or higher - add 0.005 to the reading - automated readers automatically account for this

78

What could cause a false positive on the specific gravity test?

Protein

79

What could cause a false negative on the specific gravity test?

Alkaline urine

80

Characteristic odor of PKU urine

Mousy

81

Characteristic odor of cystinosis

Sulfur

82

Characteristic odor of isovaleric acidemia

Sweaty feat

83

What is the functional unit of the kidney?

The nephron

84

What are the causes of focal segmental glomerulosclerosis?

Abuse of heroin and analgesics; AIDS

85

How to prepare specimen for microscopic examination?

Mix urine, decant 12 mL into tube. Centrifuge for 5 minutes at 400 RCF

86

What causes dirty casts?

Hemoglobin degradation products such as methemoglobin; associated with acute tubular necrosis

87

What are the three ways to determine specific gravity?

Refractometer, reagent strip, osmolality

88

What is the Acetest confirmatory for?

Ketones

89

What does the Clinitest test for?

Determines the amount of reducing substances (generally glucose) in urine

90

What is the purpose of the sulfosalicylic acid precipitation test?

It reacts equally with all types of proteins not just albumin

91

Pathogenic crystals are found in what urine pH?

Acidic, sometimes neurtral

92

What crystals are associated with liver disease?

Leucine, tyrosine, and bilirubin

93

What crystals are associated with cystinuria?

Cystine

94

What crystals are associated with nephrotic syndrome?

Cholesterol

95

What normal crystals are found in acidic urine?

Uric acid, amorphous urates

96

What crystals are seen in acid, neutral, and sometimes acidic urine?

Calcium oxalate

97

What crystals are seen in alkaline urine?

Amorphous phosphates, calcium phosphate, triple phosphate, ammonium biurate, calcium carbonate

98

What crystals precipitate after refrigeration?

Amorphous phosphates

99

What type of microscopy is typically used in urine microscopy assessment?

Bright-field microscopy

100

What is the renal threshold of glucose?

160-180 mg/dL

101

Diabetes insipidus vs diabetes mellitis

Both are pale urine; insipidus has low SG; melllitis has high SG

102

What is pyelonephritis?

Infection of the renal tubules

103

What is glmerulonephritis?

An inflammation of the glomerulus that results in impaired glomerular filtration

104

What urine findings are present in acute pyelonephritis?

Numerous leukocytes and bacteria with mild proteinuria and hematuria; WBC casts and bacterial casts may also be present

105

What urine findings are present in acute glomerulonephritis?

Macroscopic hematuria, proteinuria, RBC casts, and granular casts

106

What age group is primarily affected by Henoch-Schonlein purpura?

Children

107

What urine findings are present in Henoch-Schonlein purpura?

Macroscopic hematuria, proteinuria, RBC casts

108

What is the cause of Henoch-Schonlein purpura?

Occurs after upper respiratory infections

109

What is Lesch-Nyhan disease?

A disorder of purine metabolism that results in massive excretion of urinary uric acid crystals resembling orange sand in diapers

110

What are the urine characteristics of Fanconi syndrome?

Glycosuria with a normal blood glucose and possible mild proteinuria. Urinary pH can be low due to failure to reabsorb bicarbonate

111

What are the symptoms of acute renal failure?

Decreased glomerular filtration rate, oliguria, edema, and azotemia (steadily rising serum BUN and creatinine levels)

112

What is azotemia?

Steadily rising serum BUN and creatinine levels

113

What urine findings are present in acute renal failure?

RTE cells and casts indicate prerenal origin; RBCs indicate glomerular injury; WBC casts with or without bacteria indicate interstitial infection or inflammation or renal origin; postrenal obstruction may show normal or abnormal apperaring urothelial cells

114

What are the causes of prerenal ARF?

Decreased BP/cardiac output, hemorrhage, burns, surgery, septicemia

115

What are the causes of renal ARF?

Acute glomerulonephritis, acute tubular necrosis, acute pyelonephritis, acute interstitial nephritis

116

What are the causes of postrenal ARF?

Renal calculi and tumors

117

Good pasture syndrome and Wegener’s granulomatosis – what do we find in urine sediment?

Blood, protein, and RBC casts

118

17. Nephrotic syndrome – what do we see in urine sediment?

Heavy proteinuria, microscopic hematuria, renal tubular cells, oval fat bodies, fat droplets, fatty and waxy casts

119

What crystals are seen in nephrotic syndrome?

Cholesterol

120

What is diabetic nephropathy?

The most common cause of end-stage renal disease; caused by damage to the glomerular membrane as the result of glomerular membrane thickening and increased deposition of cellular and noncellular material within the glomerular matrix resulting in solid substances around the capillary tufts