Transaminases ALT and AST, bilirubin and blood albumin are important indicators of liver and heart health. Each of us has done a biochemical blood test at least once in our lives. When receiving its results, a reasonable question arises – where do these indicators come from and what do they say? Let’s answer these questions, and at the same time find out why ALT, AST, bilirubin and albumin are included in the so-called liver tests, and it is very important to detect deviations from the norm in time.
AST and ALT transaminases
In one minute, the liver can process and, if necessary, neutralize about a million molecules, and in an hour it cleanses about 100 liters of blood. These processes occur due to the enzymes that are found in its cells, including ALT and AST. Sometimes in the printout of the tests you can see a different abbreviation of these enzymes-ALaT and ASaT, which is basically the same thing.
ALT (alanine aminotransferase) and AST (aspartate aminotransferase) – enzymes that are synthesized in the cells of the liver, kidneys, heart, pancreas and skeletal muscles. At the same time, ALT is more in the liver, and AST is more in the heart. Normally, the enzymes are retained by the membrane (shell) of the cells of these organs, and only a small part of it circulates in the blood.
The task of ALT is to accelerate the biochemical reactions and transport the amino acid alanine to the compounds that react with it. The result of ALT is the formation of glucose from this amino acid, as well as the synthesis of new amino acids. AST is also involved in the process of glucose synthesis and the formation of aspartate. These processes are slightly more intense in men, which is associated with a slightly higher amount of ALT and AST in their blood compared to women.
By and large, for the diagnosis of the doctor is not very interested in the functions of these enzymes, because the marker of human health is only their amount in the blood. Various diseases lead to an increase in the permeability of cell membranes, and then to their destruction, and the enzymes that were there go into the blood. By the way, the norm of transaminases may differ slightly in different laboratories. Do not be confused by this, since the ALT and AST levels increase several times during the disease, and the doctor will not miss these violations. For example, with alcoholic liver damage, these indicators can be increased by 10-20 times.
ALT and AST do not have a clear organ specificity, because in addition to the liver, there are other organs whose cells contain transaminases. Therefore, it is not always possible to accurately determine the reasons for the deviation of these indicators from the norm from just one blood test. At the same time, an increase in ALT and AST levels is an alarm bell, which indicates a massive destruction of the cells of certain organs. In this case, the doctor may prescribe an additional examination, which will help determine the diagnosis.
The reasons for the increase of ALT in the blood:
- Cirrhosis and hepatitis;
- Alcoholic liver damage;
- Acute pancreatitis;
- Blockage of the biliary tract;
- Oncological diseases of the liver;
- Severe burns;
- Infectious mononucleosis;
ALT is slightly elevated when:
- Myocardial infarction;
The reasons for the decline of ALT in the blood:
- Kidney failure
- Vitamin B6 deficiency
The reasons for the increase of AST in the blood:
- Myocardial infarction, myocarditis, and heart injuries
- Toxic liver damage
- Alcoholic and fatty hepatosis
- Cirrhosis of the liver
- Violation of the outflow of bile
- Heart failure
- Oncological diseases of the liver
The de Ritis coefficient the ratio of AST/ALT. Using this indicator, the cause of the increase in transaminases is determined. Normally, it is 0.91-1.75. A decrease in the de Ritis coefficient indicates kidney damage, and an increase indicates liver damage.
It should be noted that not always an increase in ALT and AST levels indicates severe diseases that are accompanied by cell death. If the indicators increase by several units, the doctor can only observe the patient. Nevertheless, this is a reason for a more attentive attitude to your health – changing your lifestyle and following a diet.
Bilirubin is a yellow pigment, a product of the breakdown of hemoglobin. In our body, there is a constant destruction of a small number of red blood cells and the appearance of new red blood cells. The released iron goes to the formation of new red blood cells, and the protein part of the molecule is converted into bilirubin and with the help of albumin transport proteins with blood enters the liver.
The accumulation of bilirubin occurs in the gallbladder. In fact, this pigment is one of the components of bile, and accumulates in the gallbladder. When fat comes from food, the bile passes through the ducts into the duodenum, where the process of crushing (emulsifying) fat into smaller particles takes place.
Bilirubin, along with the food lump, passes further through the intestine and is excreted in the feces. At the same time, it turns the feces brown. With disorders of the liver, gallbladder and bile ducts, bilirubin enters the blood, and then into the urine. As a result, the pigment turns the skin and eyeballs yellow, and the urine a rich dark yellow or brown. Is the discoloration of feces. It takes on a light yellow or gray color. These are the symptoms of jaundice, which are characteristic of liver diseases.
In a biochemical blood test, you can find concepts such as total, direct, and indirect bilirubin. Let’s look at these indicators. Bilirubin, which is formed when red blood cells are destroyed in the blood, is called indirect or free. In the liver, indirect bilirubin reacts with glucuronic acid, and in this form enters the gallbladder. This is bound or direct bilirubin. Normally, it practically does not enter the blood, and is excreted with bile.
Albumin is a blood transport protein that binds and transports hormones, medications, and other substances necessary for the body, including bilirubin. In addition, it maintains the osmotic pressure in the blood. Albumin is synthesized in the liver, and is therefore an important diagnostic criterion for liver function.
The norm of albumin in the blood is 35-50 g/l, which is 40% – 50% of the total protein.
It is worth noting that an increase or decrease in the level of albumin does not always indicate problems with the liver. It increases in some infectious diseases, diabetes, kidney diseases, as well as in injuries and extensive burns. Another reason may be the lack of a normal drinking regime, or other options for water loss – diarrhea, vomiting. A natural decrease in the level of albumin is observed during pregnancy and during feeding, and a pathological decrease is observed in kidney diseases, oncological diseases, cardiovascular pathologies and purulent inflammations.
Other diagnostic signs may indicate that the liver has affected the amount of blood albumin. The doctor always looks at the totality of the data obtained – a general blood test, a biochemical blood test, a urine test, a liver ultrasound, CT, MRI, and many others.
Early diagnosis of liver disorders is important, as they occur long before the onset of symptoms of the disease. The liver is devoid of nerve endings, and therefore does not hurt. Pain appears when it increases, when the liver tissue begins to press on its capsule. These are usually late manifestations of the disease, and at this stage, treatment is not always effective. The liver is capable of recovery( regeneration), it is important only to establish the problem in time. It is advisable to take a biochemical blood test at least once a year, in order not to miss the onset of the disease.
Take care of your liver health!