A blood test for liver function tests: decoding and rate indicators

In liver pathologies, one of the key diagnostic procedures is the study of venous blood.

Liver tests are performed to assess the functioning of the body and identify the nature of the pathological process. Based on the results obtained, the attending physician may have an idea of ​​whether there is an acute or chronic form of the disease and how severely the liver is affected.

In this article, we will tell all about liver function tests: we will perform a transcript of the results online, show the rate of the indicators, and say how to properly prepare for the study.

Indications for study

Liver tests are necessary for:

  • suspected inflammation, infection or viral damage to the liver;
  • the need to monitor the patient's response to taking certain medications (in particular, antibiotics);
  • the need to determine the severity of liver cirrhosis;
  • patient complaints of pain in the right hypochondrium, weakness, nausea;
  • pregnancy planning;
  • the need for surgical intervention.

Liver tests are also needed to monitor the effectiveness of treatment for liver diseases.

What is included in the liver function test?

Of particular importance are the tests for:

  • alanine aminotransferase;
  • aspartate aminotransferase;
  • gamma-glutaotransferase;
  • bilirubin;
  • total protein (especially albumin);
  • alkaline phosphatase.

When liver tissue damage occurs, ALT and AST levels increase. Albumin is an indicator of how well the liver produces protein. By the level of bilirubin, it is possible to judge how the process of neutralization of toxic substances occurs by the liver cells.

However, not in all cases deviations in the indices indicate the presence of hepatic pathologies. In drawing up the overall clinical picture, as well as for making an accurate diagnosis, it is necessary to study the patient's history, physical examination and additional diagnostic tests.

How to prepare for delivery?

To get reliable research results, you need to prepare for it in advance. To do this, you must fulfill the following requirements:

  1. A few days before the test, you need to significantly reduce the intensity of physical activity.
  2. Abandon spirits, fatty, spicy and fried foods.
  3. To the extent possible, eliminate stress and nerve overstrain.
  4. A couple of days before the test, you need to smoke less and give up cigarettes on the day of the study.
  5. The day before the analysis, you need to moderately eat food and abandon tea, coffee, energy drinks.
  6. It is imperative to inform the doctor about the admission of any drugs for therapeutic purposes.
  7. On the day of the study, the stomach must be empty.

Before the analysis is allowed to drink only water, and then in small quantities. Doctors recommend tubing a week before the test.

Features changes during pregnancy

The period of childbearing exposes the woman’s body to significant changes, and at this time, liver function tests are a must. Of course, during 9 months a significant load is created on the body of the future mother, which can lead to some functional deviations. In such a situation, it is not an anomaly, but one of the indicators of the norm.

During the first trimester in the blood of a pregnant woman, the level of bilirubin decreases, but then he returns to normal. To eliminate the risk of exacerbation of liver pathologies, the expectant mother should regularly undergo liver tests.

Indicators of other liver enzymes also change: for example, in early pregnancy, there is a decrease in the concentration of ALT, which returns to normal shortly before delivery. The level of AST is also significantly reduced. GGT indices in the first and third trimester decrease, and normalize only in the middle of pregnancy.

In the first 6 months, the bilirubin index decreases, and only towards the end of pregnancy increases slightly. If the future mother had such changes, then there is no reason to worry. Provided that the levels of these substances increase or fall significantly, immediate medical intervention is necessary. But even if the deviations were not recorded, for any alarming symptoms, the woman should consult a doctor to find out the causes of the indisposition.

Features of the analysis of the indices in children

Indicators of biochemical analysis of blood in children are prone to frequent changes. However, over time they stabilize, and this happens as the child grows up. That is why the study of blood serum in young patients takes into account not only the results obtained, but also the data obtained during the survey and examination. The levels of certain enzymes can be raised or lowered - it depends on the characteristics of the hormonal background and the age of the child.

Consequently, when deciphering the research data, their interpretation will differ significantly from that in adult patients. For example, if there is an increase in the concentration of alkaline phosphatase, then in children it is considered the norm. But if such a deviation is detected in adults, it should be alerted: such changes in indicators may indicate a stagnation of bile in the body.

Before carrying out liver tests at the child, parents should inform the doctor about the time of the last meal. Equally important in this case is the usual diet of a small patient. Information about this, too, must be provided in full.

In addition, parents should notify the doctor about the child accepting any medication.

Indicators that are rarely included in the list of required tests.

Indicators of the following substances are rarely used by doctors in assessing the functioning of the liver:

  1. Lactate dehydrogenase. An increase in its level is observed with viral or toxic lesions of the liver tissues.
  2. Copper and ceruloplasmin, the determination of which is necessary if a genetic pathology such as Wilson’s-Konovalov disease is suspected.
  3. Cholinesterase. Determining its concentration helps to determine the severity of intoxication of the body, and also helps to evaluate the performance of the hepatobiliary system. Lowering the level of this substance indicates chemical poisoning. A similar deviation is also observed in patients with end-stage development of liver cirrhosis and oncological processes. A jump in cholinesterase level is observed during the development of cardiovascular pathologies.

Norm of indicators

Normal liver indexes depend on the age and gender of the patient. It is not always the doctor who makes the "verdict" after the alarming deviations in the analyzes were noted - often the test is repeated after a certain period of time.

The rate of hepatic enzymes is given in the table, which can be viewed below:

IndicatorsMenWomen
ASTUp to 47 U / lUp to 31 U / l
ALTUp to 37 U / lUp to 31 U / l
GGTUp to 49 U / lUp to 32 U / l
Total bilirubin8.5 - 20.5 µmol / L8.5 - 20.5 µmol / L
Bilirubin straightUp to 15.4 µmol / LUp to 15.4 µmol / L
Indirect bilirubinUp to 4.6 µmol / LUp to 4.6 µmol / L
Total protein60 - 80 g / l60 - 80 g / l
Albumen40-60%40-60%

If the patient does not complain of indisposition, and no strange symptoms disturb him, then even if the liver function tests showed a result above or below the norm, they can and should be repeated. This will enable the doctor to judge whether a pathological process is actually taking place, or that errors were made during the analysis.

Decryption of analyzes

The exact interpretation and interpretation of these liver function tests is carried out exclusively by a competent doctor. All information specified in this article is intended for informational purposes only!

The results of the analysis depend on where it was conducted. Each laboratory has its own methodology and technology for performing diagnostic manipulation, and its own equipment. Therefore, on the form with the results indicated the rate of a substance.

  1. Albumin is a specific protein that is found in the blood in the highest amounts and is produced by the liver cells. To diagnose liver diseases, it is more important for the doctor to know about changes in the performance of individual protein fractions than the total protein content. So, although albumin does not belong to highly sensitive indicators, deviations in its indicators may indicate the development of hepatic and renal pathologies. In addition, its concentration is influenced by various factors, in particular, unhealthy diet. An increase in albumin is observed in cirrhosis, hepatitis, rheumatism and other diseases.
  2. Total protein, indicators of which combine levels of albumin and globulin. Indicators of total protein may vary depending on changes in the levels of its components. Its decrease indicates a violation of the outflow of bile, inflammatory hepatic pathologies and cirrhosis, diseases of the gallbladder, etc.
  3. AST (aspartate aminotransferase). This substance is a liver enzyme that enters the blood in small quantities. Together with ALT, this element is a mandatory component of liver samples. In men, the level of AST should not exceed 41 units per liter of blood. For women, the rate is 31 U / l. To identify pathological processes, only indicators AST and ALT are not enough. In this case, an integrated approach is needed with an assessment of the ratio of the coefficients of other indices (the De Ritis coefficient). In a healthy person, these figures do not exceed 1. If the coefficient is increased, this may indicate development of cardiac abnormalities, or a high risk of myocardial infarction. The decrease in indicators indicates hepatic diseases, including destructive processes in its cells.
  4. ALT (alanine aminotransferase). It is the deviations from the normal indices of this substance that are considered to be one of the main signs of acute pathological processes affecting the liver. At the same time, an increase in the content of ALT in the blood occurs even before the onset of symptoms. If the tissue damage is too intense, the indicators increase tenfold. Indicators AST and ALT increase with necrosis of the liver cells, since both substances are inside the tissue of the organ and take an active part in the process of amino acid metabolism. An important diagnostic measure is the determination of the De Rytis coefficient, when the number of ALT and AST is calculated. With hepatitis viral nature, these indicators are less than one. For chronic dystrophic pathologies, the characteristic coefficient of the coefficient is 1, but sometimes the level of these substances may exceed one. In alcoholic liver diseases, the de Ritis coefficient may exceed 2.
  5. Alkaline phosphatase. By deviations from its level from the norm, one can suspect the development of cholestasis and the formation of a malignant tumor of the liver. But it is possible to judge the presence of pathological processes only if the other substances produced by the organ are also elevated. This is explained by the fact that alkaline phosphatase isozymes are contained not only in the liver, but also in bone tissue and intestinal cells. If, in addition to alkaline phosphatase, no enzymes are elevated, then we are talking about diseases not related to the liver.
  6. GTP is an important indicator, and may indicate the presence of liver disease even in the absence of abnormalities in the levels of other substances synthesized by this organ. It is an element highly sensitive to various changes in the familiar environment. The changes in the indicators of this substance can be judged on alcohol intoxication, poisoning with toxic products, gastrointestinal tract pathologies, problems with blood vessels. Increasing the concentration of GTP in the blood of women can occur against the background of prolonged or uncontrolled intake of hormonal contraceptives.
  7. Bilirubin is a specific substance that is the main indicator of the development of liver failure. With direct and indirect hepatitis, bilirubin increases. The same thing happens when the bile ducts are blocked, poisoned by hepatotoxic medications, congenital anomalies of the hepatobiliary system, etc. An increase in direct and total bilirubin may be a result of following a strict diet or undergoing a course of fasting.
  8. Prothrombin time is a simple study, the essence of which is to assess the ability of the liver to synthesize blood clotting factors. The test performance is directly influenced by the level of vitamin K in the patient’s body, therefore, it is not only liver pathology that causes them to decrease. If there was an increase in the prothrombin index, and after the introduction of vitamin K, the situation has not changed, then this indicates the development of pathological processes in the tissues of the organ.

An integrated approach to liver function tests contributes to an accurate diagnosis. Based on the results obtained, effective therapy is prescribed, aimed at relieving inflammation, relieving symptoms and improving the quality of life of the patient.

Which doctor to contact for treatment?

In order to prevent biochemical blood tests can be conducted and healthy people. However, it is often necessary to determine the level of liver enzymes if the patient has complaints of alarming symptoms.

If deviations from generally accepted standards have been identified, treatment may be carried out by an infectious disease specialist, a hepatologist, a general practitioner or a surgeon. Before prescribing tests, the doctor is obliged to instruct the patient about the rules of preparation for the study and tell about the possible consequences of the current pathology.

Watch the video: Liver Function Tests LFTs Explained Clearly by (October 2019).

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