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Clinical Chemistry (CC 1) > (M) Lec 3: Non-Nitrogenous Proteins > Flashcards

(M) Lec 3: Non-Nitrogenous Proteins Flashcards

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1
Q
  • these have low molecular weight
  • they contain nitrogen
  • are distinguished from proteins based on their size
  • are metabolic by-products/waste of proteins, nucleic acids, and muscle metabolism
A

Non-Protein Nitrogenous Compounds (NPNs)

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2
Q

A high NPN value is (advantageous or disadvantageous) to man

A

Disadvantageous

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3
Q

In what excretions (2) are a large number of NPNs found in?

A

Urine and Stool

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4
Q

In what body fluid are NPNs ideally found in small amounts/minimal concentrations?

A

Blood

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5
Q

What organ is responsible for properly excreting NPNs?

A

Kidney

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6
Q

NPNs are converted into proteins by bacteria found in the stomachs of (animals or humans)

A

Animals

Animals further convert NPNs into proteins while NPNs are the end products in humans (we lack the bacteria that convert it)

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7
Q

Where are NPNs incorporated in to increase its crude protein value which is measured based on nitrogen content?

A

Animal feeds

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8
Q

Crude protein values of NPNs in animal feeds

Protein: % N?
Urea: % N?
Melamine: % N?

A

Protein: 16%
Urea: 47%
Melamine: 66%

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9
Q

Order the NPNs from most significant to least (in %)

  • Amino acids
  • Ammonia
  • Creatine
  • Creatinine
  • Urea
  • Uric acids

I will give the percentages in the answer, just familiarize there

A
  1. Urea (45%)
  2. Amino Acids (20%)
  3. Uric Acids (20%)
  4. Creatinine (5%)
  5. Creatine (1-2%)
  6. Ammonia (0-2%)
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10
Q

What 4 NPNs are part of the parameters for a kidney function test?

A
  1. Urea
  2. Amino acids
  3. Creatinine
  4. Creatine
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11
Q

What NPN is part of the parameters for a liver function test?

A

Ammonia

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12
Q

What NPN will significantly increase if there is an increased result for NPNs in general?

A

Urea (highest concentration)

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13
Q

This NPN is technically not yet part of the “NPNs classified as waste products” as it is “not really” a protein yet

A

Amino acids

Note: From protein > amino acids > urea

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14
Q

Which among creatinine and creatine is the end product?

A

Creatinine (creatine signifies incomplete muscle metabolism)

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15
Q

Clinically Significant NPNs

This is the major excretory product of oxidative protein and amino acid metabolism

A

Urea or BUN

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16
Q

Clinically Significant NPNs

This is synthesized in the liver from CO2 and ammonia that arises from the deamination of amino acids

A

Urea or BUN

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17
Q

The synthesis of UREA in the liver from CO2 and ammonia that arises from the deamination of amino acids is known as what cycle?

Clue: It has 3 names

A
  1. Urea cycle
  2. Ornithine cycle
  3. Kreb’s Henseleit cycle
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18
Q

Urea is excreted in both urine and stool, but what percentage of it actually makes it to the urine?

A

90%

Consists of half of the urinary solids

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19
Q

Determination of Blood Concentration (UREA)

Abnormal levels of urea can give an idea about an individual’s renal function and perfusion, does it indicate acute or chronic disorders?

A

BOTH

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20
Q

Determination of Blood Concentration (UREA)

A diet rich in this component will result to high urea formation

A

High protein diet

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21
Q

Determination of Blood Concentration (UREA)

Urea is a good indicator for an individual’s state of what?

A

Hydration

Normal Urea = Hydrated
Abnormal Urea = Possible dehydration

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22
Q

Determination of Blood Concentration (UREA)

Refers to how FAST the body is able to catabolize proteins

A

Protein Catabolism Rate

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23
Q

Determination of Blood Concentration (UREA)

Urea is a good indicator for an individual’s intake of what?

A

Nitrogen

Urea has the HIGHEST nitrogen concentration among the NPNs

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24
Q

Urea Determination

This has been used to refer to a MEASUREMENT OF UREA, not the actual urea

A

Blood Urea Nitrogen (BUN)

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25
Q

Urea Determination

Actual Urea has a formula of what?

Actual urea is the level of urea minus the nitrogen

A

BUN x 2.14 mg/dL

The CF for urea is 2.14

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26
Q

Urea Determination

What is the conversion factor for actual urea when you have computed for the conventional unit (mg/dL) and would like to report it as an SI unit (mmol/L)?

Simply multiply the obtained mg/dL value with this CF to get mmol/L

A

0.357 or 0.36 mmol/L

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27
Q

Analytical Methods in Determining Urea

Which among enzymatic and chemical reactions are the direct and indirect methods for determining urea?

A

Enzymatic - indirect
Chemical - direct

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28
Q

Analytical Methods in Determining Urea (Enzymatic/Indirect Method)

  • most common enzymatic method
  • couples the urease with glutamate dehydrogenase (2 reactions)
  • the amount of NAD produced corresponds to the amount of urea
A

Coupled Urease (Glutamate Dehydrogenase) Method

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29
Q

Analytical Methods in Determining Urea (Enzymatic/Indirect Method)

In Coupled Urease (Glutamate Dehydrogenase) Method, what are the end products [2] after the coupled reactions?

A

Glutamate and H2O

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30
Q

Analytical Methods in Determining Urea (Enzymatic/Indirect Method)

In Coupled Urease (Glutamate Dehydrogenase) Method, the amount of glutamate and H2O is not the main analyte being measured, instead what it is?

A

Nicotinamide Adenine Dinucleotide (NAD)

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31
Q

Analytical Methods in Determining Urea (Enzymatic/Indirect Method)

  • ammonia will result in a color change with the help of a pH indicator
  • thiosemicarbazide and ferric ions are added to enhance color development
  • color intensity corresponds to the amount of urea

Note: W/o the reagents in the 2nd bullet, the color will be very light

A

Indicator Dye

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32
Q

Analytical Methods in Determining Urea (Enzymatic/Indirect Method)

  • urea is broken down into ammonia and bicarbonate which produces conductive activity
  • amount of conductivity produced is correspondent to the amount of urea

Note: This method has low sensitivity

A

Conductimetric

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33
Q

Analytical Methods in Determining Urea (Enzymatic/Indirect Method)

  • this measures the production of indophenol blue when phenol is added as a reagent
  • ammonia will result in a color change with the help of a pH indicator
A

Berthelot Reaction

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34
Q

Analytical Methods in Determining Urea (Enzymatic/Indirect Method)

  • urea will produce ammonia and CO2 (the ammonia can be measured by treating it with Berthelot reagents)
  • is commonly and routinely done
A

Hydrolysis of Urea (by urease)

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35
Q

Analytical Methods in Determining Urea (Enzymatic/Indirect Method)

  • this is the REFERENCE METHOD for measuring urea
  • the GOLD STANDARD
A

Isotope Dilution Mass Spectrometry (IDMS)

Note: This is not only for urea, it is also the reference method for other tests

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36
Q

Analytical Methods in Determining Urea (Chemical/Direct Method)

  • most commonly used direct method
  • diacetyl is added to urea to produce diazine
  • it appears as a yellow-colored compound
  • it is measured using a spectrophotometer and it has a higher sensitivity than other methods
A

Diacetyl Monoxime (DAM)

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37
Q

Analytical Methods in Determining Urea (Chemical/Direct Method)

In the Diacetyl Monoxime (DAM) Method, the production of diazine from the combination of urea and diacetyl is known as what reaction?

A

Fearon’s Reaction

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38
Q

Analytical Methods in Determining Urea (Chemical/Direct Method)

  • the addition of o-phthaldehyde to urea will produce isoindoline which is acted upon by N-(1-naphthyl)-ethylenediamine resulting in a colored product
  • the resulting color is dependent on the indicator added
A

O-phthaldehyde Method

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39
Q

Specimen Requirements (Urea)

What 3 bodily fluids can be used?

A
  1. Serum
  2. Plasma
  3. Urine
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40
Q

Specimen Requirements (Urea)

Urea should not be contamined with:
1. Fluoride
2. Citrate
3. Ammonia

Which among these results in false increased and false decreased values?

Note: I will explain the rationale in the results

A

Falsely decreased: Fluoride and Citrate

Falsely increased: Ammonia

Fluoride and Citrate - inhibits urease
Ammonia - a fellow NPN

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41
Q

Specimen Requirements (Urea)

TOF: You must fast before submitting a sample for urea testing

A

False (a non-fasting sample is needed)

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42
Q

Reference Values for Urea

  • For serum?
  • For 24H urine?
A

Serum: 6-20 mg/dL
Urine: 12-20 g/day

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43
Q

Disease Correlations of UREA

  • elevated levels of all nitrogenous substances (urea has the most striking prominence)
  • it has three types depending on the organ of origin
A

Azotemia

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44
Q

Disease Correlations of UREA

What are the 3 kinds of azotemia?

A
  1. Pre-renal
  2. Renal
  3. Post-renal
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45
Q

Disease Correlations of UREA

  • accumulation of NPNs in the blood due to the inability of urea to enter the kidneys (before it even arrives at the kidneys)
  • caused by conditions already existing in the blood (specifically a decrease in renal perfusion)
  • caused by dehydration, shock, and congestive heart failure
A

Pre-renal Azotemia

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46
Q

Disease Correlations of UREA

In Pre-renal Azotemia, there is a decreased rate of what but with normal renal function?

A

Glomerular Filtration Rate (GFR)

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47
Q

Disease Correlations of UREA

In Pre-renal Azotemia, increased urea comes with (decreased, normal, or increased) blood creatinine

A

Normal

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48
Q

Disease Correlations of UREA

  • the TRUE kidney disease
  • there is increased BUN due to poor excretion
  • caused by either acute or chronic kidney disease and glomerulonephritis
  • can cause coma and neuropsychiatric changes
A

Renal Azotemia

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49
Q

Disease Correlations of UREA

In Renal Azotemia, striking urea levels come with (decreased, normal, or increased) blood creatinine

A

Increased (slowly rising)

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50
Q

Disease Correlations of UREA

Renal Azotemia Criteria (give the values for the ff. analytes:)
1. BUN
2. Creatinine
3. Uric Acid

A
  1. BUN - ≥100 mg/dL
  2. Creatinine - ≥20 mg/dL
  3. Uric Acid - ≥12 mg/dL
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51
Q

Disease Correlations of UREA

  • there is marked elevation in plasma urea accompanied by acidemia and electrolyte imbalance (potassium is elevated)
  • the kidneys fail to eliminate waste products
  • characterized by anemia (normocytic normochromic), uremic frost (dirty skin of metallic color), edema, foul breath, and urine in sweat
A

Uremia

Note: Only BUN is high in this disease (because it is found in plasma)

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52
Q

Disease Correlations of UREA

What are the normal values of the BUN to CREATININE (B:C) ratio which differentiates the causes of abnormal urea in the blood?

A

10:1 to 20:1

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53
Q

Disease Correlations of UREA

Indicate if:
A. Low B:C Ratio (< 10:1)
B. Increased B:C w/ normal creatinine
C. Increased B:C w/ high creatinine

  • decreased urea production
  • low-protein diet
  • acute tubular necrosis
  • repeated dialysis
  • hepatic disease
A

A.

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54
Q

Disease Correlations of UREA

Indicate if:
A. Low B:C Ratio (< 10:1)
B. Increased B:C w/ normal creatinine
C. Increased B:C w/ high creatinine

  • pre-renal azotemia
  • high-protein intake
  • thyrotoxicosis
  • GI hemorhhage
  • dehydration
  • catabolic states
A

B.

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55
Q

Disease Correlations of UREA

Indicate if:
A. Low B:C Ratio (< 10:1)
B. Increased B:C w/ normal creatinine
C. Increased B:C with high creatinine

  • post-renal azotemia
  • pre-renal azotemia with renal disease
  • uremia
  • renal failure
A

C.

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56
Q

TOF: Urea is the hardest waste to remove in dialysis due to its abundance

A

False (the easiest)

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57
Q

Answer if increased or decreased BUN

  • azotemia (all three types)
  • fever
  • stress
  • burns
  • high-protein diet
  • dehydration
  • chronic renal disease
A

Increased

58
Q

Answer if increased or decreased BUN

  • poor nutrition
  • high fluid intake (overhydration)
  • pregnancy
  • severe liver disease
  • hormonal effects
  • malnutrition
  • hepatic diseases
A

Decreased

59
Q
  • end product of muscle metabolism
  • is not reabsorbed and minimally secreted in the kidneys
  • amount generated is proportional to the muscle mass
  • is not affected by protein intake
  • a marker for glomerular filtration rate which makes it an index for overall renal function
  • measures the completeness of 24H urine
A

Creatinine

60
Q

Once creatine is produced via muscle metabolism, it will be (dehydrated, hydrolyzed, methylated, or deaminated) to form creatinine

A

Dehydrated

61
Q

Creatinine is also produced by 3 amino acids, what are those?

A

Methionine, Arginine, and Lysine

62
Q

TOF: Creatinine is not easily removed via dialysis

A

True

63
Q

Increased or Decreased Creatinine?

  • impaired renal function
  • chronic nephritis
  • muscular diseases
  • congestive heart failure
A

Increased

64
Q

Increased or Decreased Creatinine?

  • decreased muscle mass
  • advanced and severe lung disease
  • pregnancy
  • inadequate dietary protein
A

Decreased

65
Q

Analytical Methods in Determining Creatinine

  • most frequently used and first described in 1886
  • creatinine reacts with picric acid in an alkaline solution to form a red-orange tautomer of creatinine picrate
  • has many interferences (ascorbate, glucose, uric acid, and a-ketoacids)
A

Direct Jaffe Reaction

66
Q

Analytical Methods in Determining Creatinine

This is a saturated reagent comprised of picric acid and 10% NaOH

A

Jaffe Reagent

67
Q

Analytical Methods in Determining Creatinine

  • requires automated equipment to measure the rate of change of absorbance
  • it takes more than one measurement
  • rate of color production is measured (spectrophotometer)
A

Kinetic Jaffe Method or Janovsky-like Reaction

68
Q

Analytical Methods in Determining Creatinine

  • uses creatininase or creatinine amidohydrolase, creatine kinase, pyruvate kinase, and lactate dehydrogenase
  • peroxidase may also be used in a dry slide technique
  • this eliminates the non-specificity of the Jaffe reaction as it is more specific
A

Enzymatic Method

69
Q

Analytical Methods in Determining Creatinine (Enzymatic Methods)

  • produces lactate with NAD (which are measured) as these are always directly proportional to creatinine
A

Creatininase-Creatine Kinase

70
Q

Analytical Methods in Determining Creatinine (Enzymatic Methods)

  • using peroxidase, the end product exhibits a color through the addition of an indicator to measure the color intensity
A

Creatininase-Hydrogen Peroxide

71
Q

Analytical Methods in Determining Creatinine

  • modified Jaffe reaction with adsorbent (done via elution)
  • the picric acid with adsorbent now functions to remove interferences
A

Chemical Method

72
Q

Analytical Methods in Determining Creatinine

What adsorbent is composed of sodium aluminum silicate?

A

Lloyd’s reagent

73
Q

Analytical Methods in Determining Creatinine

What adsorbent is composed of aluminum magnesium silicate?

A

Fuller’s earth

74
Q

Analytical Methods in Determining Creatinine

The reference method for creatinine measurement

A

Isotope Dilution Mass Spectrometry (IDMS)

75
Q

Specimen Requirements for Creatinine

What 3 body fluids can be used?

A
  1. Plasma
  2. Serum
  3. Urine
76
Q

Specimen Requirements for Creatinine

Creatinine requires a (fasting/non-fasting) sample

A

Non-fasting

77
Q

TOF: Protein ingestion cannot elevate creatinine levels

A

False (it can transiently elevate but only minimally)

78
Q

Interferences of Creatinine (falsely increased or decreased)

  • a-ketoacids
  • glucose
  • ascorbic acids
  • uric acid
  • cephalosporin
  • high ketones
A

False increase

79
Q

Interferences of Creatinine (falsely increased or decreased)

  • bilirubin
  • hemoglobin (hemolyzed sample)
  • contamination
A

False decrease

80
Q

Creatinine Interferences

Bilirubin and hemoglobin cause what resulting in a false decrease in results?

A

Dilution

81
Q

Creatinine Interferences

This is an anesthesia that can cause interferences in enzymatic methods

A

Lidocaine

82
Q

Creatinine Interferences

This can cause interferences in BOTH enzymatic and Jaffe reactions

A

Dopamine

83
Q

Creatinine Interferences

This causes false increased levels using Jaffe’s reaction

A

Cephalosporin

84
Q

Reference Values for Creatinine

Choices:
A. Female adult (Jaffe reaction)
B. Female adult (Enzymatic method)
C. Male adult (Jaffe reaction)
D. Male adult (Enzymatic method)
E. Children (Jaffe reaction)
F. Children (Enzymatic method)

Given: 0.6 - 1.1

A

A and D

85
Q

Reference Values for Creatinine

Choices:
A. Female adult (Jaffe reaction)
B. Female adult (Enzymatic method)
C. Male adult (Jaffe reaction)
D. Male adult (Enzymatic method)
E. Children (Jaffe reaction)
F. Children (Enzymatic method)

Given: 0.9 - 1.3

A

C.

86
Q

Reference Values for Creatinine

Choices:
A. Female adult (Jaffe reaction)
B. Female adult (Enzymatic method)
C. Male adult (Jaffe reaction)
D. Male adult (Enzymatic method)
E. Children (Jaffe reaction)
F. Children (Enzymatic method)

Given: 0.5 - 0.8

A

B.

87
Q

Reference Values for Creatinine

Choices:
A. Female adult (Jaffe reaction)
B. Female adult (Enzymatic method)
C. Male adult (Jaffe reaction)
D. Male adult (Enzymatic method)
E. Children (Jaffe reaction)
F. Children (Enzymatic method)

Given: 0.3 - 0.7

A

E.

88
Q

Reference Values for Creatinine

Choices:
A. Female adult (Jaffe reaction)
B. Female adult (Enzymatic method)
C. Male adult (Jaffe reaction)
D. Male adult (Enzymatic method)
E. Children (Jaffe reaction)
F. Children (Enzymatic method)

Given: 0 to 0.6

A

F.

89
Q

Creatinine has different reference values because it depends on the what of the individual?

A

Muscle Mass

90
Q

What is the conversion factor of creatinine to its SI unit?

A

88.7 (to umol/L)

91
Q

Creatinine 24H Urine Values

Male or Female:
800-2000 mg/dL

A

Male

92
Q

Creatinine 24H Urine Values

Male or Female:
600-800 mg/dL

A

Female

93
Q

Disease Correlations of Creatinine

Elevated creatinine in the blood is correlated to what kidney disease?

A

Renal Failure

94
Q

Disease Correlations of Creatinine

Creatinine is used in what test to measure glomerular filtration rate and how effective the kidneys are in filtering wastes in the blood

A

Clearance Test

95
Q
  • major end product of purines (adenine and guanine) metabolism
  • the final breakdown of nucleic acid catabolism in humans
  • is freely filtered but significantly reabsorbed and secreted in the tubules
A

Uric Acid

96
Q

For higher primates, uric acid is the end product of purine metabolism but in some animals, uric acid is further converted into what?

A

Allantoin

97
Q

Uric Acid

More than (>) 95% of uric acid exists as what kind of urate at a pH of 7.4 (slightly alkaline)?

A

Monosodium Urate

98
Q

Uric Acid

Uric acid at a pH of 5.4 and below exists as?

A

Uric acid (lol)

Note: It has a different form when in an alkaline environment

99
Q

Uric Acid

A concentration of > 6.4 mg/dL in plasma is considered (saturated, normal, unsaturated)

A

Saturated

100
Q

Hyperuricemia or Hypouricemia

  • leukemia
  • lymphoma
  • multiple myeloma
  • drugs, diet, and obesity
  • hypertriglyceridemia
  • renal disease
  • gout
  • Lesch Nyhan syndrome
  • ethanol consumption
A

Hyperuricemia

101
Q

Hyperuricemia or Hypouricemia

  • Fanconi’s
  • Wilson’s
  • Hodgkin’s
  • Bronchogenic CA
  • Xanthinuria
A

Hypouricemia

102
Q

Analytical Methods in Determining Uric Acid

  • the simplest and most specific method
  • is acted upon by uricase to produce allantoin
A

Enzymatic Method

103
Q

Analytical Methods in Determining Uric Acid (Enzymatic Methods)

  • measures the difference in absorbance before and after adding uricase
  • a decrease in absorbance is proportional to the uric acid content
A

Spectrophotometric

104
Q

Analytical Methods in Determining Uric Acid (Enzymatic Methods)

Uric acid is measured at a peak absorbance of what using the spectrophotometric method?

A

293nm

105
Q

Analytical Methods in Determining Uric Acid (Enzymatic Methods)

Which among the two is the Coupled Enzymatic Reaction I and II?

  1. is coupled with catalase to produce a colored compound
  2. is coupled with peroxidase to produce a colored compound
A
  1. CATALASE = enzymatic reaction I
  2. PEROXIDASE = enzymatic reaction II
106
Q

Analytical Methods in Determining Uric Acid (Chemical Methods)

  • involves a reaction with uric acid and alkaline phosphogluconate with tungsten blue as the end product
  • the principle is a redox reaction upon incubation
A

Phosphotungstic Method

107
Q

Analytical Methods in Determining Uric Acid (Chemical Methods)

In the spectrophotometric method, this additive is used in Brown’s, Benedict’s, Folin’s, and Newton’s methods

A

Sodium Bicarbonate

108
Q

Analytical Methods in Determining Uric Acid (Chemical Methods)

In the spectrophotometric method, this additive is used in Archibal’s, Caraway’s, and Henry’s methods

A

Sodium Cyanide

109
Q

Analytical Methods in Determining Uric Acid (Chemical Methods)

In spectrophotometry, this will occur after the addition of the additives to inactivate non-uric acid reactants to isolate uric acid for measurement

A

Lag Phase

110
Q

Analytical Methods in Determining Uric Acid (Chemical Methods)

The reference method for uric acid measurement

A

Isotope Dilution Mass Spectrometry (IDMS)

111
Q

Specimen Requirements for Uric Acid

TOF: Uric acid is stable in both serum and plasma for 3 days at room temperature

A

False (serum and URINE, not plasma)

The other parameters are correct

112
Q

Specimen Requirements for Uric Acid

This substance cannot be used as an anticoagulant as it can interfere with results

A

Potassium oxalate

113
Q

Specimen Requirements for Uric Acid

What are the 2 major interferences that falsely decrease results?

A
  1. Ascorbic Acid
  2. Bilirubin
114
Q

Reference Values for Uric Acid

For females?

A

2.6 - 6.0 mg/dL

115
Q

Reference Values for Uric Acid

For males?

A

0.5 - 7.2 mg/dL

116
Q

Reference Values for Uric Acid

What is the conversion factor to convert mg/dL to mmol/L?

A

0.0595

117
Q

Disease Correlations for Uric Acid (hyperuricemia)

  • pain and inflammation in the joints
  • crystals are found in the synovial fluid
  • can be treated with allopurinol
A

Gout

118
Q

Disease Correlations for Uric Acid (hyperuricemia)

  • leukemia, lymphoma, multiple myeloma, and polycythemia vera
  • can be treated with allopurinol
A

Increased nuclear metabolism

119
Q

Disease Correlations for Uric Acid (hyperuricemia)

  • due to increased GFR and tubular secretion
A

Chronic renal disease

120
Q

Disease Correlations for Uric Acid (hyperuricemia)

  • an inborn error of purine metabolism (X-linked)
  • decreased hypoxanthine-guanine phosphoribosyltransferase (HGPRT)
A

Lesch-Nyhan Syndrome (aka Juvenile Gout)

121
Q

Disease Correlations for Uric Acid (hyperuricemia)

  • glycogen storage diseases
  • toxemia of pregnancy and lactic acidosis
  • due to increased dietary intake and ethanol consumption
A

Other causes of hyperuricemia (secondary to the disease)

122
Q

Disease Correlations for Uric Acid

  • Fanconi’s syndrome (congenital tubular necrosis)
  • Wilson’s disease
  • Hodgkin’s disease
A

Hypouricemia

123
Q

What NPNs can be measured with the IDMS method?

A
  1. Urea
  2. Creatinine
  3. Uric Acid
124
Q
  • a byproduct of protein catabolism that arises from the deamination of amino acids due to the action of intestinal flora
  • also released due to skeletal muscle metabolism
  • is useful for liver function tests
A

Ammonia

125
Q

The liver removes ammonia (which is toxic) through the circulation in what vein before it is converted to urea?

A

Portal Vein

126
Q

Ammonia is converted to what in cases of severe liver disorders?

A

Glutamine

127
Q

TOF: Ammonia exists as an ion in highly acidic and alkaline pH levels

A

False (it is an ammonium ion in PHYSIOLOGICAL pH levels)

128
Q

Analytical Methods in Determining Ammonia

  • uses glutamate dehydrogenase, same in urea measurement
A

Enzymatic Method

129
Q

Analytical Methods in Determining Ammonia

  • ion-exchange
  • ion selective electrode
  • spectrophotometric
A

Chemical

130
Q

Specimen Requirements for Ammonia

  • whole blood ammonia (rises/drops) rapidly following specimen collection
A

Rises

131
Q

Specimen Requirements for Ammonia

Ammonia samples must be placed on (ice/heated blocks) to prevent the loss of ammonia

A

Ice

132
Q

Specimen Requirements for Ammonia

Air exposure can cause ammonia to (falsely increase/decrease)

A

Increase

133
Q

Specimen Requirements for Ammonia

What anticoagulants (2) are used to measure ammonia?

A

EDTA and Heparin

134
Q

Specimen Requirements for Ammonia

Centrifuge the sample in what temperature range?

A

0-4ºC

135
Q

Specimen Requirements for Ammonia

Ammonia is assayed ASAP or if frozen, it can stay stable for several days at what temperature?

A

-20ºC

136
Q

Specimen Requirements for Ammonia

(RBCs, WBCs, or platelets) contain 2-3 times as much ammonia as plasma

A

RBCs

137
Q

Specimen Requirements for Ammonia

Cigarette smoking is a significant contaminant and should be stopped how many hours prior to testing?

A

24-48 hours

138
Q

Specimen Requirements for Ammonia

If sample is hemolyzed, reject immediately as this can cause a rapid (increase/decrease) of the result upon collection

A

Increase

139
Q

Specimen Requirements for Ammonia

What is the conversion factor from ug/dL to umol/L?

A

0.587

140
Q

Please study the images on the transes for each enzymatic/chemical reaction as these may show up on the tests, and the mere descriptions in these cards may not be enough.

A

Thank you.

Clinical Chemistry (CC 1) (22 decks)

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