Chemical Examination of Urine - Intro, pH, SG, and Blood Flashcards

1
Q

What are the storage requirements for reagent strips?

A
  • Six months after opened or until the expiration date. Which ever is sooner.
  • If there is discoloration on the strips.
  • Strips remain in the container until use.
  • Keep away from sunlight and volatile fumes.
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2
Q

Discoloration of reagent strip means:

A

Loss of reactivity of reagent test pads.

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3
Q

When are quality controls done?

A
  • Performed daily.
  • New container.
  • New lot.
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4
Q

What controls are used for quality control?

A
  • Purchased positive.

- Purchased negative.

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5
Q

How is the test performed?

A
  • Un-centrifuged Urine.
  • Mix Well.
  • Dip reagent strip.
  • Start Timer.
  • Remove excess urine.
  • Read Results at appropriate times.
  • Discard Strip in biohazard waste container.
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6
Q

How is excess urine removed from the test strip?

A

Usually run it along the side of the conical tube.

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7
Q
Once reagent strips have been opened, how long before they expire?
A. I year
B. 6 months
C. 18 months
D. I month
A

B. 6 months

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8
Q

True or False: The chemical analysis should be completed on a centrifuged sample

A

False.

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9
Q

What provides the body’s acid base balance?

A
  • Kidneys.
  • Pulmonary buffers.
  • Blood buffers.
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10
Q

What is excreted to maintain the body’s pH?

A

Either hydrogen ions or ammonia ions.

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11
Q

What part of the kidney is responsible for the pH balance where it will excrete either hydrogen ions or ammonia ions?

A

In the distal convoluted tubules of the nephron.

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12
Q

If the body determines it is acidic, what will it excrete what ion?

A

Hydrogen ions. Either free or attached to phosphates or ammonia.

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13
Q

The more hydrogen ions present, the more______ the urine.

A

Acidic.

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14
Q

The fewer hydrogen ions present, the more_____ the urine.

A

Alkiline

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15
Q

What is the normal reference interval for pH?

A

4.5-8.0

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16
Q

An improperly stored urine will cause the pH to increase or decrease?

A

Increase. Over 8.0.

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17
Q

A pH of <4.5 is:

A

Physiologically impossible.

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18
Q

A pH of >8.0 is:

A

Physiologically impossible.

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19
Q

What is the “Alkaline tide”?

A

Falsely alkaline urine because the body just dumped a bunch of acid into the stomach in order to help help with digestion.

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20
Q
What interval is considered acidic urine?
A. 4.5-5.5.
B. 4.5-6.9.
C. 7.0-7.9.
D. 7.9-9.0.
A

B. 4.5-6.9

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21
Q
What interval is considered alkaline urine?
A. 4.5-5.5.
B. 4.5-6.9.
C. 7.0-7.9.
D. 7.9-9.0.
A

C. 7.0-7.9

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22
Q

What causes an acidic urine?

A

High protein diet.

  • Sleep.
  • Metabolic acidosis.
  • Respiratory acidosis.
  • UTI (E. coli).
  • Medications.
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23
Q

What causes an alkaline urine?

A
  • Vegetarian diet.
  • Metabolic alkalosis.
  • Respiratory alkalosis.
  • UTI (Proteus or Pseudomonas).
  • Medications.
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24
Q

What causes a urine pH of >8.0?

A
  • Presence of iatrogenic substance (medication).
  • Improperly stored urine.
  • Contamination with an alkaline chemical (preservative).
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25
Q

What causes metabolic acidosis?

A
  • Ketoacidosis.
  • Starvation.
  • Server diarrhea.
  • Uremia.
  • Poisons.
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26
Q

What causes respiratory acidosis?

A
  • Emphysema.

- Chronic lung disease.

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27
Q

What causes metabolic alkalosis?

A
  • Vomiting.

- Gastric lavage.

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28
Q

What causes respiratory alkalosis?

A
  • Hyperventilation
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29
Q

What is the main principle of the pH test?

A

Double indicator system. Uses a combination of acid and base indicators.
Indicator dye + hydrogen ions. Based on the pH, the hydrogen ions will get removed from the indicator, resulting in color change.

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30
Q

What are the key reagents for a pH test?

A
  • Methyl red.

- Bromthymol blue.

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31
Q

What is the pH reagent strip specificity for?

A

pH; hydrogen ion concentration.

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32
Q

What is the pH sensitivity for the chemstrip and how it is reported?

A

5.0-9.0 and in 1.0 increments.

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33
Q

What is the pH sensitivity for the multistix and how is it reported?

A

5.0-8.5 and in 0.5 increments.

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34
Q

What substance interferes with a pH test strip?

A

No known interfering substances.

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35
Q

A specific gravity of 1.010 and chronic renal failure means the patient has what condition?

A

Isosthenuria. Must be tested 3 times with the same SG.

36
Q

A specific gravity of <1.010 and is non pathogenic means a patient has what condition?

A

Hyposthenuria.

37
Q

A specific gravity of >1.010 and is non pathogenic means the patient has?

A

Hypersthenuria.

38
Q

The specific gravity test strip detects:

A

Ionic solutes excreted by the urine.

- K+, Na+, Cl-, Mg++, HCO3-.

39
Q

What is the normal reference interval for specific gravity?

A

1.003-1.035.

40
Q

A specific gravity of 1.002 - 1.035 means?

A

This is the normal specific gravity reference interval.

41
Q

A specific gravity of 1.000 means?

A

The sample is water. It is physiologically impossible for the body to have a SG this low.

42
Q

A specific gravity of 1.001 - 1.009 means?

A

Dilute urine-increased water intake or water diuresis.

43
Q

A specific gravity of 1.010 - 1.025 means?

A

Average solute and water intake.

44
Q

A specific gravity of 1.025 - 1.035 means?

A

This is concentrated urine. Associated with dehydration, profuse sweating, osmotic diuresis.

45
Q

A specific gravity of > 1.040 means?

A

This is physiologically impossible. Indicates an iatrogenic substance.

46
Q

What is the key principle for the specific gravity test strip?

A

Ionic solutes in the urine will cause the release of protons, from the polyelectrolyte which causes a change in the pH. The decrease in pH results in the bromthymol blue color indicator to be active. Thus causing a color change.

47
Q

What are the reported results for a SG test?

A

1.000-1.030. In increments of 0.005.

48
Q

What is the SG test specificity?

A

Ionized substances.

49
Q

What are the limitations of the SG test?

A

Can only be reported in increments of 0.005.

50
Q

What is the chromogen used in the specific gravity reagent pad?

A

Bromthymol blue.

51
Q

What is the key reagent for the SG on a Chemstrip?

A

Ethylene glycol-bis tetraacetic acid and Bromthymol blue.

52
Q

What is the key reagent for the SG on a Multistix?

A

Polymethylivnyl ether/maliec acid Bromthymol blue.

53
Q

What are the 3 forms of blood?

A
  • Hematuria.
  • Hemoglobinuria.
  • Myoglobinuria.
54
Q

What are two reasons blood is present in the urine?

A

Disease process or contamination.

55
Q

What form of blood is intact red blood cells?

A

Hematuria.

56
Q

What form of blood is free hemoglobin?

A

Hemoglobinuria.

57
Q

What form of blood is released due to damage to the muscles?

A

Myoglobinuria.

58
Q

A specimen from a patient with hematuria with abnormal amounts of RBC’s will appear?

A

Cloudy and red.

59
Q

How can you visually tell if a urine sample is Hematuria or Hemaglobinuria?

A

Hematuria will be cloudy and red whereas Hemoglobinuria will be clear and red.

60
Q

Glomerulonephritis is associated with which test on the strip and disease?

A

Blood and Hematuria.

61
Q

Pyelonephritis is associated with which test on the strip and disease?

A

Blood and Hematuria.

62
Q

Cystitis is associated with which test on the strip and disease?

A

Blood and Hematuria.

63
Q

Kidney Stones are associated with which test on the strip and disease?

A

Blood and Hematuria.

64
Q

Tumors are associated with which test on the strip and disease?

A

Blood and Hematuria.

65
Q

Besides the clinical correlation, what other things would cause a test strip to detect blood?

A
  • Trauma.
  • Exercise.
  • Medications.
66
Q

Hematuria means:

A

Abnormal amounts of RBC’s in the urine.

67
Q

Hemoglobinuria means:

A

Presence of free hemoglobin in the urine.

68
Q

Hemoglobinuria urine will appear?

A

Clear and red.

69
Q

Is Hemoglobinuria urine acidic or alkaline?

A

Alkaline.

70
Q

What causes Hemoglobinuria?

A
  • Intravascular hemolysis.
  • Extensive burns.
  • Infections (Clostridium perfingens).
  • Chemical toxicity (copper).
  • Exertional hemolysis (marching).
71
Q

What is myoglobinuria?

A

Heme protein of the striated muscle.

72
Q

What is Myoglobin?

A

It is a small, oxygen carrying protein that is found in the muscle.

73
Q

What causes myoglobinuria?

A
  • Muscle trauma.
  • Muscle ischemia.
  • Muscle infections.
  • Seizures.
  • Toxins.
74
Q

What causes muscle ischemia.

A

Carbon monoxide poisoning.

75
Q

Upon physical examination for blood, the urine appears red/brown. This is caused by what condition?

A

Hemoglobinuria

76
Q

If the patient has hemoglobinuria, what will the results be for blood on the reagent strip?

A

Positive.

77
Q

Upon physical examination for blood, the urine appears brown “tea colored”. This is caused by what condition?

A

Myoglobinuria.

78
Q

If the patient has myoglobinuria, what will the results be for blood on the reagent strip?

A

Positive.

79
Q

What would the CK value be for a patient with hemoglobinuria?

A

< 10X the normal limit.

80
Q

What would the CK value be for a patient with myoglobinuria?

A

> 40X the normal limit.

81
Q

What would the myoglobin result be for someone with hemoglobinuria?

A

Negative.

82
Q

What would the myoglobin result be for someone with myoglobinuria?

A

Grossly increased.

83
Q

What would the haptoglobin result be for someone with hemoglobinuria?

A

Decreased.

84
Q

What would the haptoglobin result be for someone with myoglobinuria?

A

Normal.

85
Q

What causes false positives for a blood test?

A
  • Menstrual contamination.
  • Microbial peroxidase.
  • Strong oxidizing agents such as soap or detergents.
86
Q

What causes false negatives for a blood test?

A
  • Ascorbic acid is a strong reducing agent that reacts readily with the H2O2 on the strip.
  • Chemstrip has been more proactive about this interference and developed the iodate scavengerpad that reacts with ascorbic acid first.
  • Increased specific gravity.
87
Q

What are the expected results for a blood test?

A

Negative… there shouldn’t be blood in urine.