Biochemistry Lab: Estimation of Serum Bilirubin

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Questions and Answers

What is the formula for calculating total bilirubin?

A Sample x 11.0

A Sample x 10.8 (correct)

A Sample x 10.5

A Sample x 11.5

What is the normal range of total bilirubin in serum?

Up to 1.0 mg/dL (correct)

Up to 2.0 mg/dL

Up to 0.5 mg/dL

Up to 1.5 mg/dL

What type of jaundice is caused by liver cell damage?

Pre-hepatic jaundice

Hepato-cellular jaundice (correct)

Obstructive jaundice

Haemolytic jaundice

What happens to conjugated bilirubin in obstructive jaundice?

It leaks back to the liver Signup and view all the answers

What is the main characteristic of haemolytic jaundice?

Increased RBC lysis Signup and view all the answers

What is the effect of liver cell damage on bilirubin conjugation?

Decreased conjugation of bilirubin Signup and view all the answers

What is the most common type of jaundice?

Post-hepatic jaundice Signup and view all the answers

What is the cause of increased conjugated bilirubin?

Biliary obstruction Signup and view all the answers

What is the treatment for newborn jaundice?

Phototherapy Signup and view all the answers

What happens to bilirubin when exposed to direct sunlight?

It decreases by 30% to 50% per hour Signup and view all the answers

At what temperature is serum or plasma stable for 3 months if frozen immediately?

-20 °C Signup and view all the answers

What is the effect of very high bilirubin levels?

Brain damage, muscle weakness, and eye damage Signup and view all the answers

What type of jaundice is common in newborns aged 1-3 days?

Newborn jaundice Signup and view all the answers

What is the purpose of protecting bilirubin specimens from ambient light?

To decrease its destruction Signup and view all the answers

Which of the following is NOT a source of heme in the body?

Keratin Signup and view all the answers

What is the primary function of bile?

Digestion of fats Signup and view all the answers

Which type of bilirubin is water-soluble and can be found in urine?

Conjugated bilirubin Signup and view all the answers

What is the relationship between total bilirubin, conjugated bilirubin, and unconjugated bilirubin?

Total bilirubin = Conjugated bilirubin + Unconjugated bilirubin Signup and view all the answers

Which of the following is NOT a symptom of jaundice?

Increased appetite Signup and view all the answers

What does the term 'LFT' stand for?

Liver Function Test Signup and view all the answers

Which of the following enzymes is NOT typically included in a Liver Function Test (LFT) profile?

CK Signup and view all the answers

What is the main purpose of measuring bilirubin levels in a blood test?

To assess liver function Signup and view all the answers

Study Notes

Liver Function Test (LFT) Profile

Integrity of liver cells, excretory function, and synthetic function are measured in LFT profile
Clinical lab tests include:
- Liver enzymes (AST, ALT, GGT, ALP)
- Proteins (TP, Alb, A/G ratio)
- Bilirubin

Bilirubin

Bilirubin is the water-insoluble breakdown product of normal heme catabolism
It's a yellow pigment present in bile, urine, and feces
Heme is found in hemoglobin (80%) and other hemo-proteins (20%)
There are two types of bilirubin:
- Direct bilirubin (conjugated, water-soluble)
- Indirect bilirubin (unconjugated, water-insoluble)
Total bilirubin = Direct + Indirect bilirubin

Jaundice

Jaundice is a medical term that describes the elevation of bilirubin in blood, resulting in yellow color of skin and sclera
Symptoms include nausea, vomiting, dark-colored urine, and fatigue
Types of Jaundice:
- Pre-hepatic jaundice
- Hepatic jaundice
- Post-hepatic jaundice (most common type)

Clinical Significance

Increased Conjugated Bilirubin indicates:
- Biliary obstruction
- Cancer of the head of the pancreas
Increased Unconjugated Bilirubin indicates:
- Autoimmune hemolysis
- Crigler-Najjer syndrome
- Gilbert's syndrome
- Hemolytic transfusion reaction
- Hepatitis

Newborn Jaundice

High bilirubin levels are common in newborns (1-3 days)
Factors affecting bilirubin levels in newborns:
- Rate of bilirubin level increase
- Premature birth
- Age of the baby
Treatment: phototherapy to break down bilirubin (ID → D) and convert it to the photoisomer form

Bilirubin Toxicity

Very high bilirubin levels are dangerous and toxic, causing:
- Brain damage
- Effects on muscles, eyes, and leading to death

Specimen and Storage

Fasting for at least 4 hours before the test is recommended
Bilirubin is sensitive to light and heat, so specimens should be protected from ambient light
Storage conditions:
- 1 day at 15-25°C
- 7 days at 2-8°C
- 3 months at -20°C (if frozen immediately)

Procedure for Total Bilirubin

Calculation: Total bilirubin (mg/dL) = A Sample x 10.8
Serum bilirubin levels:
- Normal: up to 1.0 mg/dL
- Unconjugated (indirect): 0.2-0.7 mg/dL
- Conjugated (direct): 0.25 mg/dL

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Description

This quiz is based on the liver function test profile, covering the estimation of serum bilirubin, liver enzymes, and proteins. It is a part of the biochemistry lab course at Almaaqal University.