Chemical Pathology of the Liver - Liver Function Tests Overview
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Questions and Answers

What can liver function tests be used for?

  • Detecting the presence of liver disease (correct)
  • Evaluating bone health
  • Investigating lung diseases
  • Predicting specific liver disorders

Which liver enzymes are considered biomarkers of liver injury?

  • LDH and CK
  • ALT and AST (correct)
  • Creatinine and urea
  • AP and GGT

What is the primary function of routine liver function tests?

  • To assess the functional hepatic cell activity in a non-routine manner
  • To indicate the nature of disease but not provide a specific diagnosis (correct)
  • To provide a specific diagnosis in most liver diseases
  • To replace the need for more advanced imaging tests

Which enzyme is linked to liver disease and the biliary tract?

<p>ALP (B)</p> Signup and view all the answers

What characteristic do most liver diseases share in terms of symptoms?

<p>They are asymptomatic at initial stages (B)</p> Signup and view all the answers

Why are liver function tests considered valuable in clinical practice?

<p>They are non-invasive and widely available (A)</p> Signup and view all the answers

Where does the degradation of bilirubin mono and di-glucuronides mainly occur?

<p>Colon (D)</p> Signup and view all the answers

What is the process by which a small amount of reabsorbed urobilinogen reaches the liver after being excreted by the intestines?

<p>Enterohepatic circulation (A)</p> Signup and view all the answers

Which organ is responsible for oxidizing urobilinogen to form urobilin?

<p>Kidneys (A)</p> Signup and view all the answers

Where does the conjugation of bilirubin occur in the liver?

<p>Endoplasmic reticulum (D)</p> Signup and view all the answers

To which plasma protein is bilirubin bound for transport to peripheral tissues?

<p>Albumin (B)</p> Signup and view all the answers

In the liver, bilirubin binds to which intracellular protein?

<p>Ligandin (A)</p> Signup and view all the answers

Which intermediate is involved in bilirubin metabolism and excretion?

<p>Urobilinogen (B)</p> Signup and view all the answers

What is the consequence of severe intrahepatic cholestasis or complete bile duct obstruction?

<p>Clay-colored stool (D)</p> Signup and view all the answers

At what serum bilirubin level does jaundice become clinically apparent?

<p>Above 50 µmol/L (A)</p> Signup and view all the answers

Where is the largest amount of alanine aminotransferase (ALT) found?

<p>Liver (D)</p> Signup and view all the answers

Which statement is true about liver function in liver disease?

<p>Increased urinary urobilinogen/urobilin and stercobilin excretion (C)</p> Signup and view all the answers

Which of the following is NOT a characteristic of jaundice?

<p>Normal serum bilirubin levels (B)</p> Signup and view all the answers

Which enzyme is specifically released by the liver in response to bile duct obstruction or impaired bile flow?

<p>5'-Nucleotidase (B)</p> Signup and view all the answers

What is the normal reference interval for serum gammaglutamyl transferase (SGGT)?

<p>2 - 15 U/L (C)</p> Signup and view all the answers

Which condition is marked by the most elevated serum GGT level?

<p>Alcoholic liver disease (D)</p> Signup and view all the answers

What reaction is catalyzed by 5'-Nucleotidase?

<p>Ribonucleotide + H2O -&gt; ribonucleoside + phosphate (D)</p> Signup and view all the answers

Which enzyme level is unrelated to osteoblastic activity according to the text?

<p>5'-Nucleotidase (A)</p> Signup and view all the answers

What enzyme is specific and sensitive for hepatobiliary disease and can be used to confirm hepatic origin of elevated serum ALP?

<p>5'-Nucleotidase (D)</p> Signup and view all the answers

Which enzyme is specifically mentioned to be elevated in cell membranes of the liver, kidney, and pancreas?

<p>Gamma-glutamyltransferase (A)</p> Signup and view all the answers

What is the main role of Albumin in the body?

<p>Maintaining osmotic pressure in the vascular system (A)</p> Signup and view all the answers

Which pair of plasma enzymes are mentioned as the most sensitive in diagnosing hepatobiliary diseases?

<p>Acid Phosphatase and 5’-nucleotidase (A)</p> Signup and view all the answers

Which group of disorders is mentioned to have elevated levels of Gamma-glutamyltransferase?

<p>Myocardial infarction, diabetes mellitus and pancreatic disease (A)</p> Signup and view all the answers

What is the specific hepatic function related to Albumin mentioned in the text?

<p>Maintaining the osmotic pressure in the vascular system (C)</p> Signup and view all the answers

Which enzyme mentioned is least likely to be involved in diagnosing hepatobiliary diseases when considering sensitivity?

<p>Lactate dehydrogenase (C)</p> Signup and view all the answers

Flashcards

Liver Function Tests (LFTs)

Tests used to evaluate liver health, diagnose liver diseases, and monitor their progress.

ALT and AST

Liver enzymes that increase when the liver is damaged or diseased.

Alkaline Phosphatase (ALP)

Enzyme linked to liver disease and biliary tract disorders.

Jaundice

Yellowing of the skin and eyes, a symptom of some liver diseases.

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Bilirubin conjugation

Process where bilirubin is modified in liver cells.

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Bilirubin metabolism

Breakdown process of bilirubin in the liver and body.

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Hepatocytes

Liver cells where bilirubin is conjugated.

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Serum bilirubin

Bilirubin in the blood.

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Jaundice appearance

Visible yellowing when serum bilirubin reaches 2-3mg/dL.

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Gamma-glutamyl transferase (GGT)

Enzyme elevated in various liver disorders.

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Albumin

Blood protein critical for blood volume and substance transport.

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Oncotic pressure

Blood pressure maintained by proteins like albumin.

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5'-Nucleotidase

Enzyme that breaks down nucleotides.

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Intrahepatic cholestasis

Liver's blockage of bile flow.

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Urobilinogen

Bile component processed by the liver and kidneys.

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Clinical appearance of jaundice

Yellowing of skin and eyes

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Portal vein

Blood vessel that brings substances to the liver.

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Bile duct block.

Obstruction of bile flow from the liver.

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Bile

Liquid processed by liver and secreted into intestines.

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Alkaline phosphatase (ALP) Source

Originates in liver, kidney and bone.

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Protein synthesis (liver)

Liver makes Albumin & other crucial proteins.

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GGT origin

GGT's high levels linked mostly to liver issues.

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Clinical Sensitivity

The ability of a test to correctly identify those with a disease.

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Clinical specificity

The ability of a test correctly identifies only those without the disease.

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Hepatobiliary diseases

Conditions affecting the liver and bile ducts.

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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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Related Documents

Chemical Pathology of the Liver (Liver Function Test I) - McGrowder - PDF

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.

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