As a doctor, I answer medical questions for my relatives and friends almost every day, half of which are the interpretation of the physical examination report. The most abstract and common one in the physical examination report is probably the liver function test form.
Because the metabolism, transformation, detoxification and other functions of the liver, all act on the whole body through blood as a carrier, so, testing the content of some components in blood can intuitively reflect the situation of liver function. Liver function indicators are mainly divided into three categories-transaminase, bilirubin and protein.
High transaminase is the most common abnormal liver function. It is a general term for a series of enzymes. It mainly includes alanine aminotransferase (glutamate), aspartate aminotransferase (glutamate), alkaline phosphatase, glutamyl transferase and lactate dehydrogenase. The lower limit of transaminase index is zero, so there will be no low transaminase, only high transaminase.
1. Abnormal liver function can lead to elevated transaminase
An important function of the liver is to convert the food eaten by people into sugar, fat and protein that can be used by the human body. After conversion, the transaminase is transported to various organs of the human body through blood. Under normal liver function, transaminase is limited to the inside of liver cells, and the amount of transaminase that can pass through the membrane of liver cells is limited. However, when hepatocytes are damaged, the permeability of cell membrane will be enhanced, and more transaminase will enter the blood, resulting in an increase in transaminase during blood detection, which is clinically manifested as abnormal liver function.
2. Elevated transaminase does not always represent abnormal liver function.
However, transaminase levels and liver dysfunction are not mutually causal. On the one hand, Not all liver function abnormalities will be manifested as transaminase elevation, many liver cancer patients’ transaminase is normal. On the other hand, transaminase is not only found in the liver, but also in the heart and muscles. Lesions in these parts may also cause transaminase elevation.
Because hepatocyte membrane is very sensitive, many behaviors and lifestyles of people will lead to its permeability increase, so the increase of transaminase does not necessarily mean the pathological changes of liver function. Easily cause the behavior of transaminase increase, lifestyle includes: strenuous exercise, overwork, drinking, greasy diet, irregular work and rest, even anger, etc.
Therefore, the simple elevation of transaminase is not a reliable indicator of whether the liver is suffering from pathological changes. Of course, a doctor should be consulted for an abnormally sharp elevation.
Only total bilirubin and direct bilirubin are listed on the test sheet. Total bilirubin is equal to direct bilirubin plus indirect bilirubin. Like transaminase, bilirubin abnormalities are only on the high side.
1. Bilirubin is a useful normal metabolite
Bilirubin is the product of normal metabolism after the death of human blood cells. Indirect bilirubin is produced after the death of red blood cells in the blood, which is converted into direct bilirubin by the liver, and then most of it will enter bile and flow into duodenum. At this time, bilirubin will turn waste into treasure and help the human body absorb fat and protein.
2. Elevated bilirubin can be manifested as jaundice.
There are three causes of jaundice:
Obstructive jaundice: Biliary tract obstruction, bile cannot be discharged, and blood flows back through biliary tract capillaries, which is called obstructive jaundice.
Hepatocellular jaundice: Hepatocytes are damaged and cannot convert indirect bilirubin into direct bilirubin, resulting in accumulation of indirect bilirubin in blood, which is called hepatocellular jaundice.
Hemolytic jaundice: There is a problem with blood, a large number of red blood cells are necrotic, excessive indirect bilirubin is produced, and the liver cannot handle it. This is called hemolytic jaundice.
No matter what kind of cause of jaundice, it means that the human body is likely to have some kind of pathological changes, so bilirubin is an indicator that doctors pay more attention to when diagnosing.
In the test form, the protein is mainly serum total protein and serum albumin. Contrary to the first two items, protein abnormalities are only on the low side.
Protein is the most referential indicator to reflect liver function. If liver function is damaged, the ability of liver to synthesize protein decreases, which will lead to a decrease in protein content in blood. Blood protein content decreases, osmotic pressure decreases, and water will run from blood circulation to tissues. Ascites, which is often accompanied by liver cirrhosis patients, is produced in this way.
These are the three major indicators that reflect liver function. Doctors need more other evidence to make clinical diagnosis. For example, in hepatobiliary surgery, doctors should also refer to whether there is ascites, whether there are symptoms of hepatic encephalopathy, and coagulation function.
Finally, please keep in mind when interpreting yourself: slight elevation of transaminase is not of great significance, but abnormal bilirubin and protein indexes need to be alerted and further examined in the hospital.