How to evaluate liver function?

Poor liver function can cause some clinical manifestations depending on the degree of liver damage. However, these symptoms may be unclear or confused with problems caused by other medical conditions. Therefore, in order to evaluate liver function, it is necessary to go through a number of laboratory tests.

Because the liver has many functions such as synthesis, metabolism, detoxification, etc., to evaluate how well these functions work, it is necessary to evaluate it through tests to evaluate liver function. .
Liver function test is a basic biochemical test used to evaluate various functions of the liver, when the patient is suspected or has signs of liver disease such as fatigue, fatigue, and fatigue. eating, vomiting, nausea, jaundice, dark urine ... or when the patient has a history of liver disease such as fatty liver, hepatitis, cirrhosis... it is necessary to monitor and evaluate the functioning of the liver.
To perform a liver function test, it is necessary to take venous blood and then go through the machine to evaluate the parameters, thereby determining whether the liver is damaged or not.

Because the liver has many different functions, there are many groups of tests in the liver function test, including:
Group of tests to assess the status of liver cell necrosis. A group of tests that evaluate excretory and detoxification functions. General functional assessment test group. Other tests to help assess liver function 2.1 Tests to assess hepatocellular necrosis These tests include AST, ALT, LDH, Ferritin tests.
AST (Aspartate aminotransferase) occurs in the cytoplasm and mitochondria of hepatocytes, in addition to a small amount in cardiac and skeletal muscle, kidney, brain, pancreas, lung, red blood cells, white blood cells. Normal AST <40 UI/L. ALT (Alanine aminotransferase) This is an enzyme mainly found in the cytoplasm of hepatocytes, so the increase in ALT is more sensitive and specific to liver damage than AST in liver diseases. Normal ALT < 40 UI/L. AST and ALT, also known as liver enzymes, are usually elevated when liver cells are damaged, causing large amounts to be released into the bloodstream. These indexes increase to 2 times the normal index, which will be valuable in diagnosing hepatocellular destruction.
LDH (Lactate dehydrogenase): This is a non-specific test for the liver because this enzyme can appear in the heart, kidneys, muscles, red blood cells, white blood cells,... If LDH increases for a long time, it is accompanied by an increase. ALT may be due to malignant infiltrative lesions of the liver. Normally, the LDH value is 5-30 UI/L. Ferritin: This is the storage form of iron in cells. Ferritin is responsible for regulating iron levels according to the body's needs. If ferritin is elevated, it may be due to a number of reasons such as inflammation causing acute or chronic hepatocellular necrosis, especially in hepatitis C virus. In addition, it can also be related to hematological diseases such as thalassemia, liver and kidney cancer, etc. If ferritin is reduced, it shows that the body is suffering from iron, blood loss, vegetarianism, .. Normally, only ferritin in men is 30-400 ng/mL, and in women it is 15 -150 ng/mL.

2.2 Test group to evaluate the function of excretion and detoxification of Bilirubin Serum Bilirubin: Bilirubin is a metabolic product of heme, a component of red blood cells and enzymes. After the old red blood cells are destroyed in the spleen, the heme nucleus is broken down into indirect bilirubin, which is fat-soluble, insoluble in water, and then transferred to the liver for conversion to direct bilirubin, which is excreted by the kidneys. and feces. Bilirubin consists of two components, direct bilirubin (TT) and indirect bilirubin (GT). Normally, the bilirubin GT value is 0.6-0.8mg/dL; TT is 0.2-0.4mg/dL. Bilirubinuria: Only in the form of bilirubin TT, because only this form is water soluble. If you have bilirubinuria, your liver may be damaged.
Urobilinogen Is a metabolite of bilirubin in the intestine, then reabsorbed into the blood and then excreted in the urine.
Normal Urobilinogen 0.2-1.2 units.
ALP (Alkaline Phosphatase): The main source of ALP is in the liver and bones. An increase in ALP to twice normal may be seen in hepatitis, cirrhosis, metastatic malignancy, or liver infiltration (leukemia, lymphoma, sarcoidosis). If ALP is elevated (3-10 times normal) it is usually due to intra or extrahepatic biliary obstruction. 5NT (5' Nucleotidase): This is a specific form of ALP for the liver, which helps to determine whether increased ALP is caused by liver or bone or physiological conditions in elderly children or pregnant women. Normal 5NT 0.3-2.6 Bonjasky/dL. GGT (G-glutamyl transferase, g-glutamyl transpeptidase): This is a very important test in the evaluation of alcoholic hepatitis. GGT is present in many different organs, but it is found in high concentrations in the columnar epithelial cells of the bile duct. Normal GGT <30U/L in women and <50U/L in men. NH3: NH3 is produced from the metabolism of proteins in the body and by bacteria living in the intestinal tract. NH3 is an endogenous toxin and the liver is responsible for detoxifying NH3 by converting it to non-toxic urea for renal excretion. Normal NH3 blood 5-69 md/dL. 2.3 Test group to evaluate the function of protein synthesis in the blood: Most of the proteins are synthesized from the liver. Serum albumin: Only the liver can synthesize albumin for the body. Because of the very good liver storage capacity and the long half-life of albumin about 3 weeks, the amount of albumin in the blood decreases only in chronic liver diseases or in cases of very severe liver damage. Normal albumin 35-55g/L. Serum Globulin: Produced from many different sources in the body, including the liver, including a variety of proteins that transport substances in the blood and antibodies that participate in the immune system. translateable. Normal globulin 20-35g/L.
Protein electrophoresis: When a patient has chronic hepatitis or cirrhosis, especially alcoholic cirrhosis, the electrophoresis chart changes, with professional knowledge, the doctor will make accurate conclusions. .

Prothrombin time (PT) The time it takes to convert prothrombin to thrombin in the presence of clotting factors. Prothrombin time is a test that helps examine the extrinsic clotting pathway.
The liver synthesizes most of the clotting factors including factors I, II, V, VII, IX, X and these factors have a short half-life. The synthesis of clotting factors requires vitamin K, except for factor V. Factor V is therefore used to distinguish impaired liver function from vitamin K deficiency.
2.4 Other tests evaluated. Liver function In addition to the important liver function tests mentioned above, a number of tests are also used to investigate before liver resection, liver transplantation or in some studies. Tests that can be used are:
Measure the clearance of BSP (bromosulfonephthalein). Measurement of indocyanine green clearance. Measure antipyrine clearance. Aminopyrine breath test. Measure caffeine clearance. Measure the ability to eliminate glucose. Depending on the patient's clinical manifestations, the doctor will assign appropriate tests or groups of tests to help diagnose liver disease. When experiencing warning signs of liver disease, you should go to reputable medical facilities to be tested to detect and treat liver disease early.