Liver Function Tests (Clinical Chemistry & Lab II) Fall 2025 PDF

University of Human Development College of Health Sciences Department of MLS Clinical Chemistry & Lab II (Practical) Lecture 1: Liver Enzyme Tests (AST/SGOT),(ALT/SGPT), (ALP) Lecturer: Bayan S. Azizi Jihad M. Hadi Fall-2025 ...

University of Human Development College of Health Sciences Department of MLS Clinical Chemistry & Lab II (Practical) Lecture 1: Liver Enzyme Tests (AST/SGOT),(ALT/SGPT), (ALP) Lecturer: Bayan S. Azizi Jihad M. Hadi Fall-2025  Introduction Liver Function Tests (LFTs) are a group of blood tests that provide important information about the state of a patient’s liver by measuring the levels of proteins, enzymes, and waste products in the blood. These tests help in assessing liver function and identifying liver damage or disease. The liver function tests include: Albumin is the main protein produced by the liver. Total protein is a measure of the total amount of two classes of proteins in the blood: albumin and globulin. 2 ALP (alkaline phosphatase), ALT (alanine transaminase), AST (aspartate transaminase), and GGT (gamma-glutamyl transferase). These are different enzymes made by the liver. Bilirubin is a byproduct of the breakdown of red blood cells. Lactate dehydrogenase (LD or LDH) is an enzyme found in almost all tissues of the body, including the liver, heart, muscles, kidneys, lungs, and red blood cells. LD is released into the blood when cells have been damaged by disease or injury. Prothrombin Time (PT) is a blood test that measures the time it takes for blood to clot. 3  Aminotransferases (Ats) Aminotransferases, also known as transaminases, are enzymes that catalyze the transfer of an amino group (transamination) from an amino acid to a keto acid. This process is critical for amino acid metabolism and the urea cycle. All ATs require pyridoxal-5-phosphate (PLP) (Vitamin B6) as an active coenzyme. The two most clinically important aminotransferases are: Alanine aminotransferase (ALT): formerly termed glutamate pyruvate transaminase (GPT). Aspartate aminotransferase (AST): formerly termed glutamate oxaloacetate transaminase (GOT). 4 Both enzymes are commonly measured in liver function tests because they are released into the bloodstream when liver cells are damaged. Liver enzymes, aspartate aminotransferase (AST), and alanine aminotransferase (ALT), are the most sensitive indicators of hepatocyte injury. Both AST and ALT are normally present in low concentrations. ALT is the more sensitive and specific test for hepatocyte injury AST, which can also be elevated in the state of cardiac arrest or muscle injury. 5  Experiment No.1 Alanine Aminotransferase (ALT) 6 Alanine aminotransferase (ALT) ALT or SGPT (serum glutamate pyruvate transaminase), is a cytoplasmic enzyme, primarily located in the liver, that is released when the cell membrane is damaged. It is a highly specific marker for liver disease. ALT is present in very high amounts in the liver and kidney, and very small amounts in the heart and skeletal muscle. It is measured clinically as a part of the diagnostic liver function test, to determine liver health. ALT has great significance within the tricarboxylic acid cycle (TCA cycle) or Krebs cycle. 7 Alanine transaminase catalyzes the interconversion of alanine and α-ketoglutarate (Oxoglutarate) to pyruvate and glutamate ALT PLP (Vit.B6) as a coenzyme 8 ALT reaction forms are important molecules in the intermediary metabolism of glucose and protein. Alanine: non-essential amino acid; involved in sugar and acid metabolism, immunity, and energy production. α-ketoglutarate (oxoglutarate) determines the rate of the citric acid cycle, protein synthesis, and protein degradation in muscle. Pyruvate carries carbon molecules into the mitochondria for further processing, in the absence of oxygen, pyruvate undergoes fermentation to produce lactate. Glutamate serves as a fuel source and also acts as an important neurotransmitter. 9 Normal Values of sGPT test ▸ Female: 7-30 IU/L (0.12-0.50 µkat/L SI units) ▸ Male: 10-55 IU/L (0.17-0.91 µkat/L SI units) 10 Contributing Factors to abnormal values of ALT/sGPT 1. Liver Diseases Hepatitis (Acute and Chronic), Alcoholic Liver Disease, Non- Alcoholic Fatty Liver Disease (NAFLD), like obesity, diabetes, hyperlipidemia, and cirrhosis. 2. Hemolysis of the blood sample may alter test results 3. Drugs that may increase ALT levels are numerous and include: ACE inhibitors, acetaminophen, anticonvulsants, heparin, lipid- lowering agents, thiazides, antibiotics 11 Elevated levels of ALT/SGPT 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: Death of liver tissue. 12  Experiment No.2 Aspartate transaminase (AST) 13 Aspartate transaminase (AST) ❖AST or SGOT (serum glutamate oxaloacetate transaminase). ❖An enzyme that occurs in two forms, cytoplasmic (AST1) and mitochondrial (AST2) ❖AST is distributed in all body tissues, but the greatest activity occurs in the liver, heart, skeletal muscle, and erythrocytes. Minimal activity occurs in the skin, kidney, and pancreas. ❖AST/GOT also reflects damage to the hepatic cells and is less specific for liver disease. ❖ AST helps diagnose various heart, muscle, or brain disorders, such as a myocardial infarction, Obstructive jaundice, Acute hepatic necrosis, and Malignant disease. 14 Aspartate transaminase catalyzes the interconversion of aspartate and α-ketoglutarate (Oxoglutarate) to oxaloacetate and glutamate PLP (Vit.B6) as a coenzyme 15 The AST reaction is essential to maintaining homeostasis in organisms. The four different molecules that can form as a result of this transamination (oxaloacetate, α-ketoglutarate, aspartate, L-glutamate) are critical to some metabolic processes. Oxaloacetate and α-ketoglutarate play a critical role in the Krebs cycle. Aspartate is important in the urea cycle and participates in gluconeogenesis. Glutamate is an important molecule in metabolic pathways associated with memory. 16  Normal Values of sGOT ▸ Female: 9-25 IU/L (0.15-0.42 µkat/L SI units) ▸ Male: 10-40 IU/L (0.17-0.67 µkat/L SI units) ▸ Elderly: Slightly higher norms ▸ Newborn: Norms two to three times higher 17 Elevated levels of AST/SGOT may indicate ▸ Acute renal disease ▸ Liver cancer ▸ Cirrhosis ▸ Hepatitis ▸ Liver necrosis ▸ Muscle inflammation ▸ Biliary obstruction 1 8 19 The AST/ALT ratio is the ratio between the concentrations of two enzymes, aspartate transaminase (AST) and alanine transaminase (ALT). ❖ An AST/ALT ratio of less than one (where the ALT is significantly higher than the AST) is suggestive of non-alcoholic fatty liver disease. ❖ An AST/ALT ratio equal to one (where the ALT is equal to the AST) is suggestive of acute viral hepatitis or drug-related liver toxicity ❖ An AST/ALT ratio higher than one (where the AST is higher than ALT) is suggestive of cirrhosis. ❖ An AST/ALT ratio higher than 2:1 (where the AST is more than twice as high as the ALT) is suggestive of alcoholic liver disease. 20 Procedure: Test Requirements: Test Tubes Bio-chemistry analyzer sGOT and sGPT test kits (include reagents of both tests Micropipettes Calibrator Specimen Collection: Non-hemolyzed serum. Stability: 2-10 days at 2-8 °C 21  Experiment No.3 Determination of Serum Alkaline Phosphatase (ALP) 22  Introduction ❖Alkaline phosphatase (ALP) is an enzyme that is present in many parts of the body, but it is primarily found in the liver, bones, intestine, placenta, and kidneys. ❖ALP is a hydrolase enzyme responsible for removing phosphate groups from many types of molecules, including nucleotides and proteins, This process of removing the phosphate group is called dephosphorylation. ❖Some major functions of ALP include protecting the intestinal tract against bacteria, aiding in digestion, breaking down fats and some B vitamins, and promoting bone formation. Also has a role in the metabolism of nucleic acids and protein synthesis. 23  ALP is used as a tumor marker that increases in the case of osteogenic sarcoma and in breast and prostate cancer that has metastasized to the bone. Alkaline phosphatase test measures the amount of this enzyme in the blood. Abnormal levels of ALP can be caused by liver problems and other types of health problems. 24  It is also often prescribed for symptoms of a possible bone disorder such as bone pain, susceptibility to bone fractures, or abnormal bone shape. Any condition that affects bone growth or causes increased activity of bone cells can affect ALP levels in the blood. For general symptoms, ALP measurement as part of a liver panel or comprehensive metabolic panel (CMP). 25  ALPin serum,catalyze the hydrolysis of nitrophenyl phosphate to nitrophenol and phosphate. Nitrophenol is a colored compound. This reaction takes place in an alkaline medium PH= 10 26  Normal Values of ALP ❖ Female: 30-100 IU/L (0.5-1.67 µkat/L) SI units) ❖ Male : 45-115 IU/L (0.75-1.92 µkat/L SI units). ❖ Elderly: Slightly higher norms ❖ Children: one to three times adult norms ❖ Pregnancy: Two to three times adult norms ❖ Levels are significantly higher in children and pregnant women. ❖ Children have high ALP levels because of their growth phase. ❖ Pregnant women typically have higher ALP values due to contributions from the placenta. 27 Possible meanings of Abnormal values of ALP Increased: Decreased: ❖ Liver disease ❖Celiac disease ❖Bone disease ❖Excessive vitamin D intake ❖Pregnancy ❖Malnutrition ❖Biliary obstruction ❖Hepatitis ❖Anemia ❖Leukemia ❖Hypothyroidism ❖Vitamin D deficiency ❖Chronic nephritis ❖Cirrhosis ❖Liver cancer ❖Pancreatitis 28 Contributing Factors to abnormal values of ALP ❖ Hemolysis of the blood may alter test results. ❖Some drugs may increase ALP levels such as estrogen, Lipid-lower agents, antibiotics, heparin, and salicylates. ❖Drugs that may decrease ALP level: cyanides, oxalates, zinc salts, propranolol. 29 Procedure: Test Requirements: Test Tubes Bio-chemistry analyzer ALP test kit (including reagents) Micropipettes Calibrator Specimen Collection: Non-hemolyzed serum. Stability: Frozen (-25 °C): 4 weeks Refrigerator 0-4 °C: 72 hours Room Temperature (25 °C): 4 hours 30