Unit 1 Bilirubin Testing

Question 1

What is bilirubin?

Answer 1

A substance that needs to be released in the body.

Question 2

What is bilirubin metabolism part of?

Answer 2

The conjugation part of the liver function.

Question 3

What happens to RBCs after 120 days?

Answer 3

They undergo apoptosis and produce bilirubin.

Question 4

What are the components of heme after it is divided?

Answer 4

Protoporphyrin and iron.

Question 5

What is protoporphyrin oxidized into?

Answer 5

Biliverdin by heme oxygenase.

Question 6

How is biliverdin converted to unconjugated bilirubin?

Answer 6

Through biliverdin reductase.

Question 7

What is another name for unconjugated bilirubin?

Answer 7

B1.

Question 8

Is unconjugated bilirubin water-soluble?

Answer 8

No, it is water-insoluble.

Question 9

What allows unconjugated bilirubin to circulate in blood?

Answer 9

Binding covalently to albumin.

Question 10

What enzyme binds unconjugated bilirubin to glucuronic acid?

Answer 10

UDPGT.

Question 11

What is conjugated bilirubin also known as?

Answer 11

B2 or direct bilirubin.

Question 12

Where does conjugated bilirubin go after formation?

Answer 12

To the intestines.

Question 13

What are the reduced forms of conjugated bilirubin in the intestines?

Answer 13

Urobilinogen and stercobilinogen.

Question 14

What percentage of stercobilin is excreted in feces?

Answer 14

0.8

Question 15

What percentage of urobilin is excreted in urine?

Answer 15

0.02

Question 16

What percentage of urobilinogen undergoes enterohepatic circulation?

Answer 16

0.18

Question 17

What happens if bilirubin accumulates in the body?

Answer 17

It can cause toxicity and jaundice.

Question 18

What is total bilirubin composed of?

Answer 18

Unconjugated bilirubin, conjugated bilirubin, and delta bilirubin if applicable.

Question 19

What is the classic diazo reaction used for?

Answer 19

Testing urine for bilirubin.

Question 20

What is the Van den Bergh reaction used for?

Answer 20

Testing serum for bilirubin.

Question 21

Is unconjugated bilirubin polar or non-polar?

Answer 21

Non-polar.

Question 22

Is conjugated bilirubin alcohol-soluble?

Answer 22

No, it is alcohol-insoluble.

Question 23

What is the main advantage of the Jendrassik-Grof method over Malloy-Evelyn?

Answer 23

It is less affected by pH, protein concentration, and hemolysis.

Question 24

What is the reference range for conjugated bilirubin in adults?

Answer 24

0.0-0.2 mg/dL.

Question 25

What is the reference range for total bilirubin in adults?

Answer 25

0.2-1.0 mg/dL.

Question 26

What is the reference range for total bilirubin in full-term infants at 24 hours?

Answer 26

2-6 mg/dL.

Question 27

What does the foam test indicate?

Answer 27

Presence of bile or bilirubin if yellow foam forms.

Question 28

What is the normal color of urine with bilirubin?

Answer 28

Amber or brown.

Question 29

What is the reference range for urobilinogen in urine?

Answer 29

0.1–1.0 Ehrlich’s unit 2 hours.

Question 30

What enzyme is associated with carbohydrate metabolism tests in the liver?

Answer 30

Glucose tolerance test enzyme.

Question 31

What type of hepatitis is transmitted via fecal-oral route?

Answer 31

Hepatitis A and E.

Question 32

What is the wavelength used in the Jendrassik-Grof method?

Answer 32

546 nm.

Question 33

What are the components of the diazo reagent?

Answer 33

Sulfanilic acid, sodium nitrite, and HCl.

Question 34

Why should bilirubin samples be protected from light?

Answer 34

To prevent photooxidation back to biliverdin.

Question 35

What is the accelerator used in the Malloy-Evelyn method?

Answer 35

50% methanol.

Question 36

What is the end color in the Jendrassik-Grof method?

Answer 36

Blue.

Question 37

What does a yellow foam indicate in the foam shake test?

Answer 37

Presence of bile or bilirubin.

Question 38

What is the reference range for unconjugated bilirubin in adults?

Answer 38

0.2-0.8 mg/dL.

Question 39

What does an increase in unconjugated bilirubin indicate?

Answer 39

Hemolytic jaundice.

Question 40

What type of sample is preferred for bilirubin testing?

Answer 40

Serum or plasma with fasting.

Question 41

What should bilirubin samples be stored in?

Answer 41

Protected containers like carbon paper or boxes.

Question 42

What is the conversion factor for total bilirubin?

Answer 42

17.1.

Question 43

What enzyme reduces biliverdin to bilirubin?

Answer 43

Biliverdin reductase.

Question 44

What substance transports unconjugated bilirubin in blood?

Answer 44

Albumin.

Question 45

What does delta bilirubin indicate?

Answer 45

A significant hepatic problem.

Question 46

What enzyme is responsible for conjugating bilirubin in the liver?

Answer 46

UDPGT.

Question 47

What percentage of urobilinogen is excreted via enterohepatic circulation?

Answer 47

0.18

Question 48

What is the significance of the Jendrassik-Grof method?

Answer 48

It measures total and direct bilirubin more accurately.

Question 49

What does the foam test detect in urine?

Answer 49

Bilirubin or bile if yellow foam is present.

Question 50

What is the significance of protecting bilirubin samples from light?

Answer 50

Prevents false decreases in bilirubin levels.

Question 51

What wavelength is used in bilirubin spectrophotometry?

Answer 51

550 nm main, 700 nm sub.

Question 52

What is the accelerator in Jendrassik-Grof?

Answer 52

Caffeine sodium benzoate.

Question 53

What are the reference ranges for bilirubin in premature infants?

Answer 53

1-6 mg/dL at 24 hours.

Question 54

What are the main products of bilirubin in the intestine?

Answer 54

Urobilinogen and stercobilinogen.

Question 55

What is the principle behind bilirubin testing?

Answer 55

Direct bilirubin reacts with diazotized sulphanilic acid to form a red azo dye.

Question 56

What is the main component of bile detected in the foam test?

Answer 56

Bilirubin.

Question 57

What is obstructive jaundice associated with?

Answer 57

Increased conjugated bilirubin.

Question 58

What is hemolytic jaundice associated with?

Answer 58

Increased unconjugated bilirubin.

Question 59

What is hepatocellular jaundice associated with?

Answer 59

Increased total bilirubin.

Question 60

What is the normal range of total bilirubin in adults?

Answer 60

0.2-1.0 mg/dL.

Question 61

What method uses methanol as an accelerator?

Answer 61

Malloy-Evelyn method.

Question 62

What is the indicator for hepatic problems in delta bilirubin?

Answer 62

Its presence in significant amounts.

Question 63

What substance gives stool its brown color?

Answer 63

Stercobilin.

Question 64

What test measures bilirubin in neonates?

Answer 64

Bilirubinometry.

Question 65

What does jaundice in infants often require for treatment?

Answer 65

Exposure to sunlight.