1S [LAB]: Bilirubin Flashcards by 3sha Ann

Q

A waste product of the hemoglobin catabolism

A

Bilirubin

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Q

In order to be conjugated, the albumin attached to the unconjugated bilirubin through what bond?

A

Covalent bond

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Q

This is responsible for the transfer of glucuronic acid to unconjugated bilirubin

A

uridine diphosphate-glucuronosyltransferase (UDGPT)

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Q

The direct bilirubin is converted into ___ by the gut bacteria

A

urobilinogen

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Q

80% of urobilinogen is excreted in the ___ in the form of ___

A

feces
stercobilin

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Q

2% of urobilinogen is excreted in the ___ in the form of ___

A

urine
urobilin

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Q

18% of urobilinogen is excreted in the ___ and reabsorbed

A

enterohepatic circulation (portal duct system)

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Q

Urobilinogen is also called ___

A

stercobilinogen

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Q

The bilirubin test using the classic diazo reaction uses which specimen?

A

Urine

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Q

The end product of bilirubin mixed with diazotized sulfanilic acid in bilirubin determination of classic diazo reaction is ___

A

colored complex

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Q

In the bilirubin determination, this specific test is considered more reliable and uses serum as its sample

A

Van Den Bergh Reaction

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Q

___ may be a sign of significant hepatic obstruction and is a conjugated bilirubin covalently bound to albumin

A

delta bilirubin

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Q

Give the reagents in total bilirubin determination

A

Bilirubin
Diazotized sulfanilic acid
Accelerator

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Q

What is the end product of bilirubin added with diazotized sulfanilic acid?

A

2 azobilirubin

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Q

Give the reagents in conjugated bilirubin determination

A

Bilirubin
Diazotized sulfanilic acid

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Q

How do we determine the measure of unconjugated bilirubin?

A

Total bilirubin - Conjugated bilirubin = Unconjugated bilirubin

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Q

Give the composition of Diazo reagent

A

Sulfanilic acid + HCl and Sodium nitrite

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Q

The two methods of bilirubin determination

A

Malloy-Evelyn
Jendrassik-Grof

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Q

The more commonly used method of bilirubin determination

A

Jendrassik-Grof

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Q

Malloy-Evelyn/ Jendrassik-Grof:

Accelerator: 50% methanol

A

Malloy-Evelyn

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Q

Malloy-Evelyn/ Jendrassik-Grof:

Acidic pH

A

Malloy-Evelyn

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Q

Malloy-Evelyn/ Jendrassik-Grof:

End color: pink to purple

A

Malloy-Evelyn

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Q

Malloy-Evelyn/ Jendrassik-Grof:

Accelerator: Caffeine Sodium Benzoate

A

Jendrassik-Grof

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Q

Malloy-Evelyn/ Jendrassik-Grof:

Alkaline pH

A

Jendrassik-Grof

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Malloy-Evelyn/ Jendrassik-Grof: End color: Blue

Jendrassik-Grof

Why is Jendrassik-Grof the more preferred method of bilirubin determination?

*Not affected by pH change *Not affected by protein concentration *Optically more sensitive *Less affected by hemolysis to a certain extent *Has minimal turbidity and a relatively constant serum blank

Result of light to bilirubin determination

False decreased (light oxidizes bilirubin to biliverdin)

The wavelength used to determine is the sample has increased bilirubin content

450 nm

In the urine, a color of ___ or __ indicates the presence of bilirubin

Amber or brown

A physical test of the urine that determines whether the sample has excess conjugated bilirubin

Foam test

Interpret the foam test result: White, small amount

Normal

Interpret the foam test result: White, large amount

Possible protein

Interpret the foam test result: Yellow, large amount

May be due to bile/ bilirubin

Reference range of urobilinogen in the urine

0.1-1.0 Ehrlich's unit (2hrs)

Reference range of urobilinogen in the feces

75-275 Ehrlich's unit/ 100g of fresh feces

How much urobilinogen is in 1 Ehrlich unit?

1mg

Synthetic function tests done in the liver

*Prothrombin time and other tests for clotting factors *Vitamin K response test *Special protein determination

Using ___ method, direct bilirubin reacts with diazotized sulphanilic acid (DSA) to form a red azo dye

Jendrassik and Grof

The absorbance of the red azo dye formed in the Jendrassik and Grof method has an absorbance of ___ and is ___ proportional to the bilirubin concentration in the sample

546 nm directly

T/F: Indirect bilirubin will react with DSA whereas the water-soluble bilirubin will only react with DSA in the presence of an accelerator

False (direct bilirubin will react directly; indirect bilirubin will need accelerator)

The accelerator used in the bilirubin testing is ___

Cetrimide (caffeine sodium benzoate may also be used)

In bilirubin testing, setup 1 should be measured at ___ nm while setup 2 is measured at ___

550 nm 700 nm

Sample to reagent ratio in bilirubin testing

1:20

In bilirubin testing, the setups are incubated at ___ for ___ minutes

37C 5 minutes

Conversion factor for bilirubin

17.1

Reference range for conjugated bilirubin

0 - 0.2 mg/dL

Conjugated bilirubin is increased in what type of jaundice?

Obstructive jaundice

Unconjugated bilirubin is increased in what type of jaundice?

Hemolytic jaundice

Conjugated and unconjugated bilirubin is increased in what type of jaundice?

Hepatocellular jaundice

Reference range for unconjugated bilirubin

0.2 - 0.8 mg/dL

Reference range for total bilirubin

0.2 - 1.0 mg/dL

Identify the effect to bilirubin measurement: Lipemia

False increase

Identify the effect to bilirubin measurement: Hemolysis

False decrease

If left unprotected from light, bilirubin values may reduce by ___ to ___ per hour

30-50

If serum or plasma is separated from cells and stored in the dark, it is stable for ___ at RT, and ___ at 4C

2 days 1 week

A candidate reference method for bilirubin determination

Jendrassik-Grof

The result of diazo reagent reacted during Jendrassik-Grof

Purple azobilirubin

The reaction with the diazo reagent is terminated by the addition of what reagent?

Ascorbic acid

In the determination of urine urobilinogen, the use of ___ maintains urobilinogen in the reduced state

Ascorbic acid

In the determination of urine urobilinogen, the use of ___ minimizes the combination of other chromogens with the Ehrlich's reagent

Saturated sodium acetate

Spectrophotometric wavelength to determine if the sample has an increased bilirubin content

450 nm