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Questions and Answers
What is the primary location of alanine aminotransferase (ALT) in the body?
What is the primary location of alanine aminotransferase (ALT) in the body?
Which coenzyme is associated with the function of alanine aminotransferase (ALT)?
Which coenzyme is associated with the function of alanine aminotransferase (ALT)?
What is one role of glutamate in the body as mentioned in the content?
What is one role of glutamate in the body as mentioned in the content?
What can cause elevated levels of alanine aminotransferase (ALT) in the bloodstream?
What can cause elevated levels of alanine aminotransferase (ALT) in the bloodstream?
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What might hemolysis of the blood sample lead to in ALT/sGPT testing?
What might hemolysis of the blood sample lead to in ALT/sGPT testing?
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In which of the following conditions might you expect a normal ALT level?
In which of the following conditions might you expect a normal ALT level?
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What abnormal condition could lead to an increase in ALT levels?
What abnormal condition could lead to an increase in ALT levels?
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Which of the following is NOT a contributing factor for abnormal ALT values?
Which of the following is NOT a contributing factor for abnormal ALT values?
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What is the normal range of ALP levels for females?
What is the normal range of ALP levels for females?
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Which condition is associated with increased ALP levels?
Which condition is associated with increased ALP levels?
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What factor is known to potentially decrease ALP levels?
What factor is known to potentially decrease ALP levels?
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Why do children typically have higher ALP levels?
Why do children typically have higher ALP levels?
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What are the two forms of aspartate transaminase (AST)?
What are the two forms of aspartate transaminase (AST)?
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What is the stability duration for non-hemolyzed serum at room temperature for ALP testing?
What is the stability duration for non-hemolyzed serum at room temperature for ALP testing?
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Which body tissues have the greatest activity of AST?
Which body tissues have the greatest activity of AST?
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Which of the following conditions can elevated AST levels indicate?
Which of the following conditions can elevated AST levels indicate?
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What is a critical role of oxaloacetate and α-ketoglutarate in the body?
What is a critical role of oxaloacetate and α-ketoglutarate in the body?
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What indicates a non-alcoholic fatty liver disease in the AST/ALT ratio?
What indicates a non-alcoholic fatty liver disease in the AST/ALT ratio?
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What coenzyme is essential for the AST reaction?
What coenzyme is essential for the AST reaction?
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What is the normal AST level range for adult males?
What is the normal AST level range for adult males?
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What metabolic process is aspartate particularly important for?
What metabolic process is aspartate particularly important for?
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What is the primary protein produced by the liver?
What is the primary protein produced by the liver?
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Which enzyme is considered more sensitive and specific for hepatocyte injury?
Which enzyme is considered more sensitive and specific for hepatocyte injury?
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What is the role of pyridoxal-5-phosphate (PLP) in aminotransferases?
What is the role of pyridoxal-5-phosphate (PLP) in aminotransferases?
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Which test measures the time it takes for blood to clot?
Which test measures the time it takes for blood to clot?
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Which enzyme can also be elevated in cases of cardiac arrest or muscle injury?
Which enzyme can also be elevated in cases of cardiac arrest or muscle injury?
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What is the significance of measuring total protein in the blood?
What is the significance of measuring total protein in the blood?
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What type of enzyme is lactate dehydrogenase (LD or LDH)?
What type of enzyme is lactate dehydrogenase (LD or LDH)?
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Which of the following is NOT included in liver function tests?
Which of the following is NOT included in liver function tests?
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What does an AST/ALT ratio equal to one suggest about a patient's liver condition?
What does an AST/ALT ratio equal to one suggest about a patient's liver condition?
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Which condition is indicated by an AST/ALT ratio higher than 2:1?
Which condition is indicated by an AST/ALT ratio higher than 2:1?
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What is the primary location of alkaline phosphatase (ALP) in the human body?
What is the primary location of alkaline phosphatase (ALP) in the human body?
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What role does alkaline phosphatase play in the body?
What role does alkaline phosphatase play in the body?
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Which health conditions can cause elevated levels of alkaline phosphatase?
Which health conditions can cause elevated levels of alkaline phosphatase?
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What does an alkaline phosphatase test measure?
What does an alkaline phosphatase test measure?
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In which type of cancer is alkaline phosphatase often used as a tumor marker?
In which type of cancer is alkaline phosphatase often used as a tumor marker?
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Which procedure is required for measuring alkaline phosphatase in serum?
Which procedure is required for measuring alkaline phosphatase in serum?
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Study Notes
Liver Function Tests
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Liver function tests (LFTs) are a group of blood tests that assess liver function and identify liver damage or disease by measuring levels of proteins, enzymes, and waste products in the blood.
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Albumin is the main protein produced by the liver, and total protein measures the combined amount of albumin and globulin.
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Alkaline phosphatase (ALP), alanine transaminase (ALT), aspartate transaminase (AST), gamma-glutamyl transferase (GGT), bilirubin, and lactate dehydrogenase (LD or LDH) are also included in LFTs.
Aminotransferases
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Aminotransferases catalyze amino group transfer (transamination) from an amino acid to a keto acid, crucial for amino acid metabolism and the urea cycle.
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All aminotransferases require pyridoxal-5-phosphate (PLP) (vitamin B6) as a coenzyme.
Alanine Aminotransferase (ALT)
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ALT, also known as SGPT, is a cytoplasmic enzyme predominantly located in the liver, released when the cell membrane is damaged.
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It's a highly specific marker for liver disease and present in high amounts in the liver and kidney, with minimal amounts in the heart and skeletal muscle.
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ALT plays a significant role in the tricarboxylic acid cycle (TCA cycle) or Krebs cycle, catalyzing the interconversion of alanine and α-ketoglutarate to pyruvate and glutamate.
ALT Normal Values
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Female: 7-30 IU/L (0.12-0.50 µkat/L)
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Male: 10-55 IU/L (0.17-0.91 µkat/L)
Factors Affecting ALT Levels
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Liver diseases like hepatitis, alcoholic liver disease, non-alcoholic fatty liver disease (NAFLD), and cirrhosis.
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Hemolysis of the blood sample.
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Numerous medications can increase ALT levels, including ACE inhibitors, acetaminophen, anticonvulsants, heparin, lipid-lowering agents, thiazides, and antibiotics.
Elevated ALT Levels May Indicate
- Alcoholic liver disease
- Liver cancer
- Biliary obstruction
- Hepatitis or inflammation of the liver
- Use of medicines or drugs toxic to the liver
- Cirrhosis
Aspartate Transaminase (AST)
- AST, or SGOT, is an enzyme that exists in two forms: cytoplasmic (AST1) and mitochondrial (AST2).
- AST is present in all body tissues, with the highest activity found in the liver, heart, skeletal muscle, and erythrocytes.
- AST reflects damage to hepatic cells but is less specific for liver disease than ALT.
- AST helps diagnose various heart, muscle, or brain disorders like a myocardial infarction, obstructive jaundice, acute hepatic necrosis, and malignant disease.
AST Normal Values
- Female: 9-25 IU/L (0.15-0.42 µkat/L)
- Male: 10-40 IU/L (0.17-0.67 µkat/L)
- Elderly: Slightly higher norms
- Newborn: Norms two to three times higher than adults.
Factors Affecting AST Levels
- Acute renal disease
- Liver cancer
- Cirrhosis
- Hepatitis
- Liver necrosis
- Muscle inflammation
- Biliary obstruction
AST/ALT Ratio
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The AST/ALT ratio helps differentiate liver disease causes.
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A ratio less than one (ALT higher than AST) suggests non-alcoholic fatty liver disease.
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A ratio equal to one (ALT equal to AST) suggests acute viral hepatitis or drug-related liver toxicity.
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A ratio greater than one (AST higher than ALT) suggests cirrhosis.
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A ratio greater than 2:1 (AST more than twice as high as ALT) suggests alcoholic liver disease.
Alkaline Phosphatase (ALP)
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ALP is an enzyme found in various parts of the body, including the liver, bones, intestine, placenta, and kidneys.
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It's a hydrolase enzyme responsible for removing phosphate groups from molecules (dephosphorylation).
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ALP functions include protecting the intestinal tract, aiding in digestion, breaking down fats and some B vitamins, promoting bone formation, as well as contributing to nucleic acid and protein synthesis.
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ALP is used as a tumor marker that increases in cases of osteogenic sarcoma and metastatic bone cancers.
ALP Normal Values
- Female: 30-100 IU/L (0.5-1.67 µkat/L)
- Male: 45-115 IU/L (0.75-1.92 µkat/L)
- Elderly: Slightly higher norms
- Children: One to three times adult norms
- Pregnancy: Two to three times adult norms
Factors Affecting ALP Levels
- Hemolysis of the blood sample.
- Medications like estrogen, lipid-lowering agents, antibiotics, heparin, and salicylates can increase ALP levels.
- Medications like cyanides, oxalates, zinc salts, and propranolol can decrease ALP levels.
Elevated ALP Levels May Indicate
- Liver disease
- Bone disease
- Pregnancy
- Biliary obstruction
- Hepatitis
- Leukemia
- Vitamin D deficiency
- Cirrhosis
- Liver cancer
- Pancreatitis
Decreased ALP Levels May Indicate
- Celiac disease
- Excessive vitamin D intake
- Malnutrition
- Anemia
- Hypothyroidism
- Chronic nephritis
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Description
Test your knowledge on liver function tests, including the key enzymes and proteins involved in assessing liver health. Understand the significance of aminotransferases, particularly alanine aminotransferase (ALT), in metabolic processes and liver function. This quiz covers crucial topics in clinical biochemistry related to liver testing.
