U4 LAB: URIC ACID Flashcards

1
Q

Byproduct of purine nucleic acid catabolism

A

Uric Acid

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2
Q

Main form in plasma

A

Monosodium urate

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3
Q

Clinical applications

A
  • confirm diagnosis and monitor treatment of gout
  • prevent uric acid nephropathy during chemotherapeutic treatment
  • assess inherited disorders of purine metabolism
  • detect kidney dysfunction
  • assist in diagnosis of renal calculi
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4
Q

Non specific method and requires protein removal

A

Caraway method

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5
Q

Caraway Method

based on reduction of ________ in alkaline solution to tungsten blue

A

phosphotungstic acid

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6
Q

More specific and more commonly used

A

Enzymatic (Uricase) method

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7
Q

Uricase is used to catalyze ______ of uric acid to?

A

oxidation, allantoin

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8
Q

Measures the hydrogen peroxide produced as uric acid

A

Coupled enzymatic reaction

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9
Q

Coupled enzymatic reaction measures?

A

hydrogen peroxide

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10
Q

Coupled enzymatic reaction

Color produced is?

A

directly proportional to uric acid

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11
Q

Coupled enzymatic reaction

Sources of error

A

reducing agents (bilirubin and ascorbic acid)

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12
Q

This method measures differential absorbance before and after incubation with uricase.

A

Spectrophotometric assay

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13
Q

Spectrophotometric assay

Absorbance is measured at what wavelength?

A

293 nm

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14
Q

Spectrophotometric assay

What is directly proportional to uric acid?

A

difference

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15
Q

Spectrophotometric assay

Sources of error

A

protein, hemoglobin, xanthine

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16
Q

Uses UV detection

A

HPLC

17
Q

Specimens for Uric Acid

A
  • heparinized plasma
  • serum
  • urine
18
Q

Buffer

A
  • Phosphate buffer (pH 7.0)
  • EHSPT
  • Amino-4-antipyrine
19
Q

Standard uric acid

A

6 mg/dl or 0.357 mmol/L

20
Q

Pipet solutions using what volume?

A

0.25uL

21
Q

Wavelength

A

546nm

22
Q

Reference Valuesโ€™

Male

A

3.5-7.2 mg/dL

23
Q

Reference Values

Female

A

2.6-6.0 mg/dL

24
Q

Reference Values

Child

A

2.0-5.5

25
Q

Reference Values

Urine

A

250-750