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[MT 6317] Clinical Chemistry Laboratory > [2S] UNIT 9.1 Urea > Flashcards

[2S] UNIT 9.1 Urea Flashcards

1
Q

Nitrogen-containing compounds measured after removal of proteins in specimen

A

Non-Protein Nitrogen

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2
Q

Measured by converting nitrogen to ammonia and subsequent reaction with Nessler’s reagent (K2[Hgl4]) to form a yellow product measured spectrophotometrically

A

Non-Protein Nitrogen

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3
Q

NPNs specimen

A

Serum, Urea & Plasma (SUP)

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4
Q

URINE OR PLASMA

Assesses the kidney

A

Both

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5
Q

URINE OR PLASMA

For urea concentration test

A

Urine

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6
Q

Also known as carbamide

A

Urea

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7
Q

Most abundant NPN (50%)

A

Urea

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8
Q

Produced in the liver from amino groups (-NH2) and free ammonia

A

Urea

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9
Q

Major excretory product of protein metabolism

A

Urea

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10
Q

Chemical formula of Urea

A

CO(NH2)2

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11
Q

CLINICAL APPLICATIONS

Evaluation of renal function

A

Urea

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12
Q

CLINICAL APPLICATIONS

Assess hydration status

A

Urea

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13
Q

CLINICAL APPLICATIONS

Determination of nitrogen balance

A

Urea

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14
Q

CLINICAL APPLICATIONS

Aid in the diagnosis of renal disease

A

Urea

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15
Q

More appropriate term for quantification of urea

A

Blood Urea Nitrogen (BUN) Determination

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16
Q

CLINICAL APPLICATIONS

Verify adequacy of dialysis

A

Urea

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17
Q

T/F: DIALYSIS - ↑ BUN = dialysis isn’t compensating

A

T

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18
Q

Conversion factor of BUN (mg/dL to mmol/L)

A

0.357

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19
Q

BUN DETERMINATION

Most frequently used method

A

Enzymatic Method

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20
Q

BUN DETERMINATION

Uses urease enzyme to catalyze hydrolysis of urea and the liberated ammonium ion (NH4
+) is quantified.

A

Enzymatic Method

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21
Q

BUN DETERMINATION

Most common assay

A

ENZYMATIC: Glutamate dehydrogenase (GLDH)-coupled enzymatic reaction

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22
Q

BUN DETERMINATION

Best as a kinetic measurement

A

ENZYMATIC: Glutamate dehydrogenase (GLDH)-coupled enzymatic reaction

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23
Q

BUN DETERMINATION

Measures rate of disappearance of nicotinamide adenine dinucleotide (NADH) at 340 nm

A

ENZYMATIC: Glutamate dehydrogenase (GLDH)-coupled enzymatic reaction

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24
Q

BUN DETERMINATION

Used in automated systems, multilayer film reagents and dry reagent strips

A

ENZYMATIC: Indicator Dye

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25
Q

BUN DETERMINATION

Measures color change due to change in pH

A

ENZYMATIC: Indicator Dye

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26
Q

BUN DETERMINATION: ENZYMATIC

T/F: NADH is indirectly proportional to ammonia

A

F; directly (ammonia originates from the urea)

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27
Q

BUN DETERMINATION

A specific and rapid test

A

ENZYMATIC: Conductometric

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28
Q

BUN DETERMINATION

Uses electrode to measure rate of increase in conductivity produced by ammonium ions

A

ENZYMATIC: Conductometric

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29
Q

BUN DETERMINATION

Reference method

A

ENZYMATIC: Isotope Dilution Mass Spectrometry (IDMS)

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30
Q

BUN DETERMINATION

Used isotopically-labeled compound for quantification

A

ENZYMATIC: Isotope Dilution Mass Spectrometry (IDMS)

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31
Q

BUN DETERMINATION

Detects characteristic fragments following ionization

A

Isotope Dilution Mass Spectrometry (IDMS)

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32
Q

T/F: Urine should be diluted

A

T bcs mas maraming urea sa urine

33
Q

Dilution factor of Urine

A

1:20 with NSS

34
Q

Irritate the eyes and skin

A

Reagent 2: NADH, sodium azide

35
Q

Standard urea

A

50 mg/dL or 8.33 mmol/L (may vary depending on manufacturer)

36
Q

What type of urine is refrigerated?

A

24 hr urine sample

37
Q

For the reduction of NADH to NAD (reagent)

A

Reagent 2: NADH, sodium azide

38
Q

5 Reagent 1

A

RAUGAS

R1 Tris buffer (pH 7.6)
ADP
urease
glutamate
α-ketoglutarate
sodium azide

39
Q

_ absorbance = ↑ conc. of urea

40
Q

ASSAY REQUIREMENTS

Wavelength: ____
Optical path: ____
Temperature: ____
Read against ______ _____

A

Wavelength: 340 nm
Optical path: 1 cm
Temperature: 37 ͦC
Read against distilled water

41
Q

Conversion factor of urea to BUN

A

0.466 x C (Urea)

42
Q

Conversion factor of BUN to urea

A

2.14 x C (BUN)

43
Q

Reference intervals for BUN in adults’ plasma / serum

A

CU = 6-20 mg/dL
SI = 2.1-7.1 mmol/L

44
Q

Reference intervals for BUN in adults’ 24 hr urine

A

CU = 12-20 g/day
SI = 0.43-0.71 mmol/day

45
Q

Elevated urea concentration in blood

46
Q

Increased urea level accompanied by renal failure

A

Uremia / Uremic Syndrome

47
Q

Before the kidney

48
Q

Most of the time due to reduced renal blood flow

49
Q

Less renal blood delivered to the kidney, less urea filtered and excreted in the kidney; increased urea levels

50
Q

↑ Urea & Normal Creatinine

51
Q

↑ Urea & Creatinine

52
Q

Normal Urea & ↑ Creatinine

A

Post-Renal

53
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

● Congestive heart failure
● Shock

54
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

● Hemorrhage
● Dehydration

55
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

Increased protein catabolism

56
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

High-protein diet

57
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

Acute and chronic renal failure

58
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

Renal disease (glomerular nephritis and tubular necrosis)

59
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

Urinary tract obstruction

A

Post-Renal

60
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

● Renal calculi
● Tumor in the bladder or prostate
● Severe infections

A

Post-Renal

61
Q

T/F: DECREASED CONCENTRATION

The decrease of urea in the body is due to the slow metabolism of proteins in the body

62
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

Low protein intake

A

Decreased Concentration

63
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

Liver disease

A

Decreased Concentration

64
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

Severe vomiting and diarrhea

A

Decreased Concentration

65
Q

CAUSES OF ABNORMAL PLASMA UREA CONC

Pregnancy

A

Decreased Concentration

66
Q

BUN:Urea ratio

67
Q

Measures the amount of nitrogen in your blood that comes from the waste product Urea

68
Q

PROCEDURE

Read Absorbance 1 (A1) at ___?

69
Q

PROCEDURE

Set-up the spectrophotometer at _____ wavelength

70
Q

PROCEDURE

Continue the timer and read Absorbance 2 (A2) at
exactly?

A

90 seconds

71
Q

Not excreted in urine

A

Amino acids

72
Q

Reabsorbed immediately by the proximal convoluted chain through active transport

A

Amino acids

73
Q

Urea cycle in what organ

74
Q

Due to the reduced renal function that causes an increase in plasma concentration as a result of compromised urea excretion

75
Q

Problem in filtering the urea because of issues in the glomerulus

76
Q

Most likely due to the obstruction of urine flow in the urinary tract

A

Post-Renal

77
Q

After the kidney

A

Post-Renal

78
Q

Measures a chromogen produced directly from Urea

A

Direct Method

[MT 6317] Clinical Chemistry Laboratory (10 decks)

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