[2S] UNIT 9.3 Creatinine Flashcards

1
Q

Formed from creatine and creatine phosphate

A

Creatinine

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2
Q

Product of muscle catabolism

A

Creatinine

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3
Q

99% excreted in urine

A

Creatinine

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4
Q

Creatinine is filtered in?

A

Glomerulus

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5
Q

3 Factors affecting creatinine level

A

Muscle Mass
Creatine Turnover
Renal Function

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6
Q

Creatine loses _____ to form a cyclic compound known as creatinine

A

water

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7
Q

Creatine phosphate loses _______ ____

A

phosphoric acid

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7
Q

↑ muscle mass _ creatinine level

A

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8
Q

↑ plasma creatinine _ glomerular filtration rate

A

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9
Q

CLINICAL APPLICATIONS

T/F: Determine the sufficiency of kidney function

A

T

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10
Q

CLINICAL APPLICATIONS

T/F: Determine the severity of heart damage

A

F; kidney damage

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11
Q

CLINICAL APPLICATIONS

T/F: Monitory progression of kidney disease

A

T

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12
Q

ANALYTICAL METHODS

● Most frequently used method
● First described in 1886

A

Chemical Methods Based of Jaffe Reaction

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12
Q

ANALYTICAL METHODS

Principle: In alkaline medium: Creatinine + picric acid → Creatinine-picrate complex (orange red)

A

Chemical Methods Based of Jaffe Reaction

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13
Q

ANALYTICAL METHODS

The intensity of orange red product is directly proportional to amount of creatinine present

A

Chemical Methods Based of Jaffe Reaction

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14
Q

ANALYTICAL METHODS: CHEMICAL METHODS BASED OF JAFFE REACTION

Creatinine in a protein-free filtrate is adsorbed onto
fuller’s earth (aluminum magnesium silicate) or
Lloyd’s reagent (sodium aluminum silicate), then
eluted and reacted with alkaline picrate

A

Jaffe w/ Adsorbent

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14
Q

ANALYTICAL METHODS: CHEMICAL METHODS BASED OF JAFFE REACTION

Non-specific and prone to false positive reactions
with:
○ Ascorbic acid
○ Glucose
○ Glutathione
○ Alpha-keto acids
○ Uric acid
○ Cephalosporins

A

Folin-Wu Method (w/o Adsorbent)

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15
Q

ANALYTICAL METHODS: CHEMICAL METHODS BASED OF JAFFE REACTION

Creatinine in protein-free filtrate reacts with alkaline
picrate to form colored complex

A

Folin-Wu Method (w/o Adsorbent)

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15
Q

ANALYTICAL METHODS: CHEMICAL METHODS BASED OF JAFFE REACTION

Measuring multiple absorbance

A

Jaffe Kinetic

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16
Q

ANALYTICAL METHODS: CHEMICAL METHODS BASED OF JAFFE REACTION

The rate of change in absorbance is measured to
avoid interference of non-creatinine chromogens

A

Jaffe Kinetic

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16
Q

ANALYTICAL METHODS: CHEMICAL METHODS BASED OF JAFFE REACTION

Not routinely used because it is time consuming and
not readily automated

A

Jaffe w/ Adsorbent

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16
Q

ANALYTICAL METHODS: CHEMICAL METHODS BASED OF JAFFE REACTION

False positives
○ Alpha-keto acids
○ cephalosporins

A

Jaffe Kinetic

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17
Q

ANALYTICAL METHODS: CHEMICAL METHODS BASED OF JAFFE REACTION

Routinely performed because
○ Inexpensive
○ Rapid
○ Easy to perform

A

Jaffe Kinetic

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17
Q

ANALYTICAL METHODS: CHEMICAL METHODS BASED OF JAFFE REACTION

Serum is mixed with alkaline picrate

A

Jaffe Kinetic

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18
Q

ANALYTICAL METHODS: CHEMICAL METHODS BASED OF JAFFE REACTION

False negatives
○ Bilirubin
○ Hemoglobin

A

Jaffe Kinetic

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19
Q

ENZYMATIC METHODS

● Adapted for use as dry slide method
● Potential to replace Jaffe reaction

A

Creatininase - H2O2

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20
Q

ENZYMATIC METHODS

● False positives
○ lidocaine
● False negatives
○ Ascorbic acid - interfere with peroxidase reaction

A

Creatininase - H2O2

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21
Q

ENZYMATIC METHODS

Uses series of enzymatic catalyzed reaction

A

Creatininase - H2O2

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22
Q

ENZYMATIC METHODS

○ Conversion of Creatinine to creatine
○ First enzyme used for analysis

A

Creatininase

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23
Q

ENZYMATIC METHODS

Lacks sensitivity and not used widely

A

Creatininase-CK

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24
Q

ENZYMATIC METHODS

Creatine to sarcosine and urea

A

Creatinase

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25
Q

ENZYMATIC METHODS

Sarcosine is oxidized to form formaldehyde,
glycine, and peroxide

A

Sarcosine oxidase

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26
Q

ENZYMATIC METHODS

○ Measured via peroxidase reaction
○ Peroxidase reaction will produce water and oxygen

A

Peroxidase

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27
Q

ENZYMATIC METHODS

○ The oxygen released is used to oxidize the indicator (colorless substrate)
○ Once the indicator is oxidized, it will form a
colored product

A

Peroxidase

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28
Q

ENZYMATIC METHODS

● As NAD+ is produced, it is measured as a decrease in
absorbance
● Reduction in NADH is the one being measured

A

Creatininase-CK

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29
Q

ENZYMATIC METHODS

Decrease in the absorbance is proportional to the level of creatinine in the sample

A

Creatininase-CK

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30
Q

● Accepted reference method
● Highly specific

A

Isotope Dilution Mass Spectrometry

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31
Q

● Detects characteristic fragment following ionization
● Quantifies creatinine using isotopically labeled
compound

A

Isotope Dilution Mass Spectrometry

32
Q

Specimens used

A

plasma, serum, or urine

33
Q

T/F: Fasting is not required

A

T

34
Q

T/F: High protein ingestion may transiently elevate serum concentration, it is significant to increase creatinine level

A

F; not significant

35
Q

T/F: Hemolysis, lipemia, and icteric samples should be avoided

A

T

36
Q

T/F: If samples cannot be processed immediately, it can be refrigerated

A

T

37
Q

T/F: Samples that are not processed for more
than 4 days or within 4 days can be freezed

A

T

38
Q

Creatinine Reagent Kit R1

A

Picric Acid

39
Q

Creatinine Reagent Kit R2

A

Sodium hydroxide, disodium phosphate

40
Q

Standard Creatinine

A

2 mg/dl or 176.8 mmol/L

41
Q

Ratio of R1 & R2

A

1:1

41
Q

Set up the spectrophotometer at ___ nm

A

520

42
Q

ASSAY REQUIREMENTS

● Wavelength:
● Optical path:
● Temperature:
● Read against _______ _____ (the blank used)

A

520 nm
1 cm
37 C
distilled water

43
Q

Feed the solution in the machine at __ seconds, read and record absorbance as A1

A

10

44
Q

Continue the timer and at exactly ___ seconds, read
and record again the absorbance as A2

A

120

45
Q

T/F: With regards to creatinine concentration, it is very dependent by body mass

A

T

46
Q

Computed to determine the glomerular filtration rate

A

Creatinine Clearance

47
Q

Usually used to estimate the capacity of glomerulus to filter substances in the plasma

A

Creatinine Clearance

48
Q

Used to approximate glomerular filtration rate (GFR)

A

Creatinine Clearance

48
Q

Things that you should consider for the determination of ___________ is
○ the analyte should be or almost 100% is excreted in the urine
○ it should be endogenously produced by the body

A

glomerular filtration rate

49
Q

Among all of our analytes, _______ is the best candidate for approximation of the glomerular filtration rate – called the creatinine clearance

A

creatinine

50
Q

Measure of the amount of creatinine eliminated from
the blood by the kidneys

A

Creatinine Clearance

51
Q

Male Creatinine Clearance

A

97-137 mL/min

52
Q

Creatinine clearance unit

A

mL/min

53
Q

Female Creatinine Clearance

A

88-128 mL/min

54
Q

CLINICAL SIGNIFICANCE

Impaired renal function

A

Increased

55
Q

CLINICAL SIGNIFICANCE

Acute kidney injury

A

Increased

56
Q

CLINICAL SIGNIFICANCE

Low muscle mass

A

Decreased

56
Q

CLINICAL SIGNIFICANCE

Chronic kidney disease

A

Increased

57
Q

Jaffe Plasma Reference Range Female Adult

A

0.6 - 1.1 mg/dL / 53 - 97
umol/L

58
Q

CLINICAL SIGNIFICANCE

Undernutrition

A

Decreased

59
Q

CLINICAL SIGNIFICANCE

Muscle wasting

A

Decreased

60
Q

CLINICAL SIGNIFICANCE

Muscular dystrophies

A

Decreased

61
Q

Jaffe Plasma Reference Range Male Adult

A

0.9 - 1.3 mg/dL / 80 - 115 umol/L

62
Q

Jaffe Plasma Reference Range Child

A

0.3 - 0.7 mg/dL / 27 - 62 umol/L

63
Q

Jaffe 24 h Urine Reference Range Male

A

800-2000 mg/day / 7.1 - 17.7 mmol/day

64
Q

Jaffe 24 h Urine Reference Range Female

A

600 - 1800 mg/day / 5.3 - 15.9 mmol/day

65
Q

Enzymatic Plasma Reference Range Male Adult

A

0.67 - 1.1 mg/dL / 53 - 97 umol/L

66
Q

Enzymatic Plasma Reference Range Female Adult

A

0.5 - 0.8 mg/dL / 44 - 71 umol/L

67
Q

Enzymatic Plasma Reference Range Child

A

0.0 - 0.6 mg/dL / 0 - 53 umol/L

68
Q

Considered as the best overall indicator of the level of kidney function

A

GFR

69
Q

Gauged by measuring excretion of substance that is only minimally reabsorbed and secreted by the renal tubules

A

GFR

70
Q

↑ creatine, ↑ urinary creatinine, _ plasma creatinine:
○ Muscle diseases
○ Muscular dystrophy
○ Poliomyelitis,
○ Hyperthyroidism
○ Trauma

A

N

70
Q

most widely used marker for GFR, SINCE:
○ Produced at a constant rate
○ Not bound to protein
○ Not reabsorbed by the renal tubules
○ Only small amount is secreted by the tubules
(10%)

A

Creatinine

71
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

Impaired renal function

A

Increased Serum Creatinine

72
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

Chronic Nephritis

A

Increased Serum Creatinine

73
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

Congestive heart failure

A

Increased Serum Creatinine & Decreased Creatinine Clearance

74
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

High cardiac output

A

Increased Creatinine
Clearance

75
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

Decreased muscle mass

A

Decreased Serum Creatinine

76
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

Advanced and severe liver
disease

A

Decreased Serum Creatinine

77
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

Pregnancy

A

Decreased Serum Creatinine & Increased Creatinine
Clearance

77
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

Burns

A

Increased Creatinine
Clearance

78
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

Carbon monoxide poisoning

A

Increased Creatinine
Clearance

79
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

Impaired kidney function

A

Decreased Creatinine Clearance

80
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

Shock, dehydration

A

Decreased Creatinine Clearance

81
Q

CLINICAL SIGNIFICANCE: SERUM / CREATININE CLEARANCE

Hemorrhage

A

Decreased Creatinine Clearance