Podcast
Questions and Answers
What can liver function tests be used for?
What can liver function tests be used for?
Which liver enzymes are considered biomarkers of liver injury?
Which liver enzymes are considered biomarkers of liver injury?
What is the primary function of routine liver function tests?
What is the primary function of routine liver function tests?
Which enzyme is linked to liver disease and the biliary tract?
Which enzyme is linked to liver disease and the biliary tract?
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What characteristic do most liver diseases share in terms of symptoms?
What characteristic do most liver diseases share in terms of symptoms?
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Why are liver function tests considered valuable in clinical practice?
Why are liver function tests considered valuable in clinical practice?
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Where does the degradation of bilirubin mono and di-glucuronides mainly occur?
Where does the degradation of bilirubin mono and di-glucuronides mainly occur?
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What is the process by which a small amount of reabsorbed urobilinogen reaches the liver after being excreted by the intestines?
What is the process by which a small amount of reabsorbed urobilinogen reaches the liver after being excreted by the intestines?
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Which organ is responsible for oxidizing urobilinogen to form urobilin?
Which organ is responsible for oxidizing urobilinogen to form urobilin?
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Where does the conjugation of bilirubin occur in the liver?
Where does the conjugation of bilirubin occur in the liver?
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To which plasma protein is bilirubin bound for transport to peripheral tissues?
To which plasma protein is bilirubin bound for transport to peripheral tissues?
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In the liver, bilirubin binds to which intracellular protein?
In the liver, bilirubin binds to which intracellular protein?
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Which intermediate is involved in bilirubin metabolism and excretion?
Which intermediate is involved in bilirubin metabolism and excretion?
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What is the consequence of severe intrahepatic cholestasis or complete bile duct obstruction?
What is the consequence of severe intrahepatic cholestasis or complete bile duct obstruction?
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At what serum bilirubin level does jaundice become clinically apparent?
At what serum bilirubin level does jaundice become clinically apparent?
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Where is the largest amount of alanine aminotransferase (ALT) found?
Where is the largest amount of alanine aminotransferase (ALT) found?
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Which statement is true about liver function in liver disease?
Which statement is true about liver function in liver disease?
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Which of the following is NOT a characteristic of jaundice?
Which of the following is NOT a characteristic of jaundice?
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Which enzyme is specifically released by the liver in response to bile duct obstruction or impaired bile flow?
Which enzyme is specifically released by the liver in response to bile duct obstruction or impaired bile flow?
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What is the normal reference interval for serum gammaglutamyl transferase (SGGT)?
What is the normal reference interval for serum gammaglutamyl transferase (SGGT)?
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Which condition is marked by the most elevated serum GGT level?
Which condition is marked by the most elevated serum GGT level?
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What reaction is catalyzed by 5'-Nucleotidase?
What reaction is catalyzed by 5'-Nucleotidase?
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Which enzyme level is unrelated to osteoblastic activity according to the text?
Which enzyme level is unrelated to osteoblastic activity according to the text?
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What enzyme is specific and sensitive for hepatobiliary disease and can be used to confirm hepatic origin of elevated serum ALP?
What enzyme is specific and sensitive for hepatobiliary disease and can be used to confirm hepatic origin of elevated serum ALP?
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Which enzyme is specifically mentioned to be elevated in cell membranes of the liver, kidney, and pancreas?
Which enzyme is specifically mentioned to be elevated in cell membranes of the liver, kidney, and pancreas?
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What is the main role of Albumin in the body?
What is the main role of Albumin in the body?
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Which pair of plasma enzymes are mentioned as the most sensitive in diagnosing hepatobiliary diseases?
Which pair of plasma enzymes are mentioned as the most sensitive in diagnosing hepatobiliary diseases?
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Which group of disorders is mentioned to have elevated levels of Gamma-glutamyltransferase?
Which group of disorders is mentioned to have elevated levels of Gamma-glutamyltransferase?
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What is the specific hepatic function related to Albumin mentioned in the text?
What is the specific hepatic function related to Albumin mentioned in the text?
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Which enzyme mentioned is least likely to be involved in diagnosing hepatobiliary diseases when considering sensitivity?
Which enzyme mentioned is least likely to be involved in diagnosing hepatobiliary diseases when considering sensitivity?
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Study Notes
Liver Function Tests and Their Uses
- Liver function tests (LFTs) are used to assess liver health, diagnose liver diseases, and monitor the progression of existing conditions.
- Biomarkers of liver injury include levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST).
- Routine liver function tests primarily evaluate the liver's capacity to synthesize proteins and metabolize substances.
Enzymes Linked to Liver Disease
- Alkaline phosphatase (ALP) is linked to liver disease and biliary tract disorders.
- Increased liver enzymes, particularly ALT and AST, typically indicate liver damage or disease.
Common Symptoms in Liver Diseases
- Most liver diseases share common symptoms, including jaundice, fatigue, and abdominal swelling.
Clinical Importance of Liver Function Tests
- Liver function tests are valuable in clinical practice for diagnosing liver disorders, monitoring treatment efficacy, and detecting complications.
Bilirubin Processing
- Degradation of bilirubin mono- and di-glucuronides mainly occurs in the liver.
- After excretion by the intestines, a small amount of reabsorbed urobilinogen reaches the liver via the portal vein.
- Urobilinogen is oxidized to form urobilin primarily in the kidneys.
Bilirubin Conjugation and Transport
- Conjugation of bilirubin occurs in hepatocytes (liver cells) of the liver.
- Bilirubin is transported to peripheral tissues bound to the plasma protein albumin.
- Inside the liver, bilirubin binds to the intracellular protein ligandin.
Bilirubin Metabolism and Clinical Observations
- Bilirubin metabolism involves an intermediate called bilirubin glucuronide.
- Severe intrahepatic cholestasis or complete bile duct obstruction can lead to an increase in serum bilirubin levels, causing jaundice.
- Jaundice becomes clinically apparent at a serum bilirubin level of approximately 2-3 mg/dL.
Enzyme Distribution and hepatobiliary Diseases
- The highest levels of alanine aminotransferase (ALT) are found in the liver.
- In liver disease, liver function is often impaired, leading to decreased production of proteins, including albumin.
- Gamma-glutamyl transferase (GGT) levels are typically elevated in a variety of liver disorders.
Specific Enzymes and Their Roles
- The enzyme 5'-Nucleotidase catalyzes the hydrolysis of nucleotides to nucleosides and phosphates.
- Alkaline phosphatase (ALP) levels are unrelated to osteoblastic activity.
- GGT is a sensitive enzyme for hepatobiliary disease and can confirm the hepatic origin of elevated ALP.
- The enzyme elevated in cell membranes of the liver, kidney, and pancreas is alkaline phosphatase.
Role of Albumin and Diagnostic Enzymes
- Albumin plays a critical role in maintaining oncotic pressure and transporting various substances in the blood.
- ALT and AST are mentioned as the most sensitive plasma enzymes in diagnosing hepatobiliary diseases.
- Elevated levels of GGT are often associated with liver disorders.
Specific Functions and Diagnostic Sensitivity
- Albumin’s specific hepatic function includes the transportation of hormones and drugs in the bloodstream.
- Among the mentioned enzymes, GGT is the least likely to be involved in diagnosing hepatobiliary diseases when considering sensitivity.
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Description
Learn about the functions of the liver, bilirubin production and metabolism, and routine liver function tests including enzymes like ALT, AST, ALP, GGT, albumin, direct and total bilirubin. This quiz provides an overview of liver function tests (LFTs) which are clinical biochemistry laboratory blood assays used to assess the state of the liver.