Questions and Answers
What is the coenzyme required for aspartate aminotransferase?
Which tissue is NOT a major source of aspartate aminotransferase?
What condition is associated with the highest elevation of aspartate aminotransferase?
Which isoenzyme of aspartate aminotransferase is NOT routinely analyzed?
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Which of the following does NOT represent a condition related to skeletal muscle involvement with aspartate aminotransferase elevation?
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In what situation would aspartate aminotransferase levels NOT be expected to increase?
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Which enzyme is also referred to as serum glutamic-oxaloacetic transaminase?
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Which of the following conditions can lead to elevated aspartate aminotransferase levels due to circulatory collapse?
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What is the preferred sample type for testing alanine aminotransferase?
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What is the EC code number for Alkaline Phosphatase?
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Which of the following tissues is the major source of alanine aminotransferase?
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In which condition is alanine aminotransferase elevation typically not found?
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Which tissue sources are associated with Alkaline Phosphatase?
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Which of the following methods can be used to differentiate normal ALP isoenzymes?
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What is the significance of the De Ritis Ratio when assessing liver function?
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Which of the following conditions is associated with the highest elevation of alanine aminotransferase?
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What type of cancer is associated with the Regan isoenzyme of Alkaline Phosphatase?
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Which abnormal Alkaline Phosphatase isoenzyme is linked to metastatic carcinoma of pleural surfaces?
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What is a common clinical use of alanine aminotransferase testing?
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Which isoenzyme is specifically associated with adenocarcinoma of the pancreas and bile duct?
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Which of the following does NOT represent a condition that typically causes elevated alanine aminotransferase levels?
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What enzyme cofactor is required for alanine aminotransferase activity?
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What process is used to differentiate normal Alkaline Phosphatase isoenzymes apart from chemical inhibition?
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Which chromosome is associated with intestinal and placental ALP isoenzymes?
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Which enzyme is the most heat stable among alkaline phosphatase isoenzymes?
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What does neuraminidase do in the context of alkaline phosphatase separation?
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Which of the following conditions can cause pronounced elevation of alkaline phosphatase by 5 or more times the upper limit of normal?
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L-phenylalanine inhibits which types of alkaline phosphatase?
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What is the role of wheat germ lectin in alkaline phosphatase testing?
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What is the effect of 20% ethanol on liver amino phosphatase compared to bone ALP?
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Which two alkaline phosphatase types are inhibited by levamisole?
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What is the primary purpose of using high-resolution electrophoresis in alkaline phosphatase testing?
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What could cause a moderate elevation in alkaline phosphatase levels?
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Which condition is associated with slight elevation of alkaline phosphatase levels during pregnancy?
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What is a consequence of hemolysis during the processing of alkaline phosphatase samples?
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Which assay method is recommended by IFCC for measuring alkaline phosphatase?
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What condition is directly related to decreased alkaline phosphatase levels?
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Which factor could lead to a 25% higher alkaline phosphatase value?
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What is the optimum pH for the Bowers Mc Comb method?
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Which of the following is NOT an illness associated with alkaline phosphatase elevation?
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Study Notes
Liver Enzymes Overview
- Focus on enzyme determination methods, clinical significance, and patient preparation.
- Explore tissue sources and specimen considerations for specific enzymes.
Aspartate Aminotransferase (AST)
- Also known as serum glutamic-oxaloacetic transaminase (SGOT).
- Coenzyme: pyridoxal phosphate; key tissue sources include cardiac tissue, liver, and skeletal muscle; minor sources include kidney, pancreas, and erythrocytes.
- Isoenzyme fractions: cytoplasmic (not routinely analyzed) and mitochondrial.
Clinical Significance of AST
- Elevated levels indicate hepatocellular disorders, skeletal muscle involvement, and acute myocardial infarction.
- Highest elevation observed in acute hepatocellular disorders and myocardial infarction, with increases of 5 or more times the upper limit of normal (ULN).
- Additional causes of elevation: circulatory collapse (shock), acute pancreatitis, and infectious mononucleosis.
Specimen Considerations for AST
- Preferred specimen: fresh, un-hemolyzed serum; plasma may also be used.
Alanine Aminotransferase (ALT)
- Known as serum glutamic pyruvic transaminase (SGPT); coenzyme: pyridoxal phosphate.
- Major tissue sources are the liver and kidney, with other sources including heart and skeletal muscle.
Clinical Significance of ALT
- Primarily related to liver diseases; notable exclusions include hepatic cirrhosis and liver neoplasia.
- The De Ritis ratio (AST:ALT) is significant, with a value greater than 1 indicating potential liver issues.
- Highest elevation typically observed in non-alcoholic asymptomatic patients; mild elevations associated with Hepatitis C infection.
Methodologies for ALT Determination
- Wroblewski and La Due method based on specific reactions; also includes alternate methods like Reitman-Frankel and chemiluminescence.
Alkaline Phosphatase (ALP)
- EC code number: 3.1.3.1; essential for various body functions including bone metabolism.
- Major tissue sources include the liver, small intestine, and kidney.
ALP Isoenzymes
- Isoenzymes differentiated using techniques like electrophoresis, heat denaturation, and chemical inhibition.
- Abnormal isoenzyme fractions include Regan, Nagao, and Kasahara, each linked to specific cancers.
Clinical Significance of ALP
- Pronounced elevation (5 or more times ULN) associated with conditions like bile duct obstruction and biliary cirrhosis.
- Moderate elevation (3-5 times ULN) linked to granulomatous liver diseases and metabolic bone diseases.
- Slight elevation up to 3 times ULN tied to viral hepatitis, cirrhosis, and normal growth in children.
Decreased Levels of ALP
- Associated with inherited conditions such as hypophosphatasia or loss of bone isoenzyme.
Specimen and Assay Considerations for ALP
- Avoid hemolysis; timely processing required due to ALP activity increase and interactions with the clot.
- Serum should be prioritized over plasma for accurate measurements.
Assessment Methods for ALP
- Notable methods include Bowers McComb, electrophoresis, heat stability tests, and chemical inhibition techniques.
- Bowers McComb is recognized as the IFCC recommended method with specific substrate and pH requirements.
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Description
This quiz explores the various aspects of liver enzymes including their tissue sources, clinical significance, patient preparation, and methods of enzyme determination. Ideal for students in medical laboratory science, it fosters understanding of liver enzyme functions and applications in clinical settings.
