Elevated concentration of AFP in the blood test. What does an AFP blood test mean? Alpha-fetoprotein: decoding

And - a very important period in a woman's life. You can take care of the health of the child at the very beginning of pregnancy, and modern medicine and technology can provide effective assistance in this. In particular, a variety of things can explore the body of a woman and her baby.

Among them may be a blood test for AFP. In this article, we will try to find out what it is - alpha-fetoprotein during pregnancy, why it is so important and how it is measured.

Properties and significance for the body

AFP is an abbreviation, the decoding of which means "alpha-fetoprotein". AFP analysis during pregnancy is a way to detect and prevent the development of defects.

Alpha-fetoprotein is formed during the development of the embryo and fetus. This protein was discovered in 1944, but scientists have not yet fully understood all of its properties and functions. It is known that alpha-fetoprotein is initially produced by the yellow body of the ovaries of a pregnant woman, and then, from the 5th week, the fetus can already produce it itself.
It is synthesized by the liver and gastrointestinal tract of the embryo; it is a precursor of albumin. Of great importance is the ability of AFP to protect the unborn baby from rejection by the mother's immune system. Also, its function is to transport oxygen to the body of the fetus.

How AFP levels change during pregnancy

At the 5th week of pregnancy, the embryo is already ready to independently begin to produce alpha-fetoprotein, which is necessary so that the mother's immunity does not reject the new organism developing in her. In the process of growth and development of the baby, the level will gradually increase. The embryo releases it into the amniotic fluid in the womb, from where it enters her bloodstream, and then is excreted from her body through the process of natural metabolism.

The concentration of alpha-fetoprotein in the mother's blood, respectively, will increase over time and reach a maximum value of 32-, after which it will begin to decrease. The protein level returns to normal closer to the time when the child is one year old, and becomes the same as in a healthy adult.
The optimal time for diagnosing the level of AFP in the body of a pregnant woman is 12-. The data obtained during this period are the most valuable for the study.

Important! The control of alpha-fetoprotein during pregnancy is very important for the health of the unborn baby. It can reveal fetal pathologies or obstetric mothers. You need to know that AFP levels change every week.

Indications for analysis for alpha-fetoprotein

Arriving at an appointment with an obstetrician-gynecologist, a pregnant woman may be prescribed an analysis to control the concentration of alpha-fetoprotein in the blood, based on her condition and history.

There are a number of medical indications, in the presence of which the doctor may recommend taking an AFP test during pregnancy:

age over 35 years;
spouses are close relatives;
the presence in the anamnesis of one of the spouses or close relatives of genetic diseases, malformations;
the birth of children with malformations and / or diseases that are inherited;
spontaneous and stillbirth;
primary infertility or primary amenorrhea;
taking medications that are prohibited for pregnant women in the I and II trimester, as indicated in the annotation to the medication;
x-ray study.

Procedure for preparing and conducting analysis

Doctors recommend testing for alpha-fetoprotein at 13-15 weeks, because this is the period when the result of the study in pregnant women is most accurate.
To obtain the most informative and reliable analysis result, the procedure for preparing for it should be as follows:

Cancel the intake of medications 1-2 weeks before the planned date of delivery, and if this is not possible, then be sure to inform the doctor at the point of delivery of the analysis, indicating the data on which particular drugs they are and the dosage in which they are taken. Accumulating in the body of a woman, the substances that make up the drugs can affect the result of the examination.
Exclude alcoholic beverages, spicy, salty, fatty and fried foods from the diet of a pregnant woman on the eve of delivery.
Limit physical activity on the body of a pregnant woman, namely carrying weights and active physical exercises for 1-2 days.
The test for alpha-fetoprotein passes strictly on an empty stomach and this is an important condition. The last meal should be at least 8 hours before the analysis. In the morning on the day of blood donation, it is allowed to drink only 100-200 ml.

Analysis during pregnancy: norms and deviations

A blood test for alpha-fetoprotein during pregnancy can be taken from the 12th week to the 30th. During this period, its concentration can give a lot of information about the health of the expectant mother and the process of intrauterine development of the baby.

Since the level of AFP during pregnancy changes every day, there are norms for its concentration by week, which are convenient to consider in the table:
If, as a result of the AFP analysis, a discrepancy between the norms is found, the gynecologist may prescribe additional studies that can give a clearer picture of the health of the woman and the fetus. It is mandatory to carry out in order to accurately determine the gestational age. In the process of performing the study, the doctor can visually confirm the indicators and possible malformations of the embryo.

Important!A deviation from the norms of the level of alpha-fetoprotein in the blood of a pregnant woman can be an important signal for the doctor. Timely identified discrepancies will allow for effective treatment or timely pregnancy.

Additionally, the doctor may refer the patient to the study of placental hormones in order to understand the state of the fetoplacental system. It is also recommended to pass a triple test, which includes an analysis for AFP, hCG and free estriol. The data obtained as a result of the survey will allow us to assess the risk of malformations in the fetus and take the necessary measures to maintain the health of the mother and child.

The norms for the analysis of AFP and hCG during pregnancy are shown in the table:

Physiological norms of content

The physiological norms of the alpha-fetoprotein indicator, obtained as a result of a blood test, range from 10 ng / ml to 8 IU / ml.

Did you know?By the end of the pregnancy, the placenta produces the same amount of estrogen as the gonads of a non-pregnant woman for three whole years.

AFP deviation from the norm is measured in units called MoM, which are standard for all laboratory studies. This is an indicator of the ratio of the real level of alpha-fetoprotein to the median (the average value of the content of alpha-fetoprotein in the blood). The median value is normal if it is between 0.5 MoM and 2.5 MoM.
Deciphering the analysis of AFP during pregnancy will show whether the deviation from the norms and medians is significant. Using the MoM indicator, it is possible to compare the value of analyzes obtained in different laboratories and carried out by different methods. Research can be done using:

immunochemical method;
enzyme immunoassay.

To find out what it says and what a blood test for AFP shows, you should consider the causes of increased and decreased concentrations of alpha-fetoprotein and its effect on the body of a pregnant woman and on the intrauterine development of the fetus.

Increased concentration of AFP

An increase in the level of alpha-fetoprotein in the blood of a pregnant woman means that there may be:

multiple pregnancy;
large fruit;
malformation of the neural tube of the fetus;
fetal liver necrosis;
pathology of the kidneys of the fetus and urinary tract;
umbilical hernia of the fetus;
Shereshevsky-Turner syndrome.

Decreased concentration of AFP

If the concentration of AFP in the body of a pregnant woman is below normal, this may mean:

Down syndrome in the embryo (provided that the study was carried out after the 10th week of pregnancy);
Patau syndrome;
trisomy 18;
intrauterine growth retardation;
fetal death or missed pregnancy;
risk of spontaneous miscarriage.

Summing up, it should be said that the analysis for the level of alpha-fetoprotein is an important medical study that must be submitted within the time specified by the doctor, without fail adhering to the indicated recommendations. Timely examination of a pregnant woman can prevent the risk of developing fetal pathologies and save his life. And only a qualified doctor can do such an analysis, so do not be afraid to contact him for help.

Alpha-fetoprotein (AFP): during pregnancy and as a marker, blood norm and deviations

For the diagnosis of various diseases, dozens of blood indicators are examined, which make it possible to determine problems in the body not only in adults and children, but also at the stage of intrauterine development in the fetus. One of these markers is AFP, the level of which increases with malformations. In addition, AFP reflects the presence of certain tumors.

For the first time, the alpha-fetoprotein protein was discovered in the serum of embryos and adults by American scientists in the first half of the last century. It was called alpha-fetoprotein due to the fact that it was specific to embryos.

More detailed studies have been carried out by Russian biochemists since the second half of the 20th century. Analyzing tumor growth, it was found the presence of AFP in the blood serum of patients with liver cancer, which made it possible to refer it in 1964 to the tumor markers of this organ. It also became clear that alpha-fetoprotein is formed during pregnancy and in certain concentrations is its normal manifestation. These studies were a breakthrough in biochemistry and were registered in the USSR Register of Discoveries.

Professor Yu. S. Tatarinov proposed a test for AFP in blood serum, which to this day remains the only one in the diagnosis of hepatocellular carcinoma.

Today, expectant mothers are most interested and want to know about this indicator, because its concentration can indicate a serious pathology and developmental disorders of the fetus. Let's try to figure out what AFP is and how to interpret the results of research.

Properties and significance of AFP for the body

Alpha-fetoprotein is a special protein produced by embryonic tissues (yolk sac, intestinal cells, hepatocytes). In adults, only traces of it can be found in the blood, and in fetuses, the concentration of AFP is significant, which is due to the functions it performs. In a developing organism, AFP is similar to adult albumin, it binds and transports various substances, hormones, and protects the tissues of the unborn baby from the mother's immune system.

An important ability of AFP is its binding of polyunsaturated fatty acids. These components are needed to build cell membranes, synthesize biologically active substances of prostaglandins, but they are not formed either by the tissues of the embryo or in the mother's body, but come from outside with food, so their delivery to the right place depends only on specific carrier proteins.

Having an important influence on the growth of the fetus, AFP must be present in the required amount in accordance with the gestational age. At the first stages of fetal development, AFP is synthesized by the corpus luteum of the mother's ovary, and by the 13th week of pregnancy, its concentration in the blood and amniotic fluid becomes significant.

After the laying of the liver and intestines in the baby, their cells themselves produce AFP for their own needs, but significant amounts of it penetrate through the placenta and into the mother's blood, therefore by the third trimester of gestation, at 30-32 weeks, AFP becomes maximum in the expectant mother.

By the time a child is born, his body begins to produce albumin, which takes over the functions of fetal protein, and the concentration of AFP gradually decreases during the first year of life. In normal adults, only traces of AFP can be detected, and its increase indicates a serious pathology.

AFP is a marker that is determined not only during pregnancy, but also in pathologies of internal organs

The determination of AFP is used as one of the screening indicators of the normal course of pregnancy. , which changes with various developmental anomalies, malformations, congenital syndromes. It should immediately be noted that the result does not always accurately indicate the presence or absence of pathology, therefore, the assessment of its fluctuations should be carried out in conjunction with other studies.

In adults, a mild increase in alpha-fetoprotein usually indicates abnormal liver function.(cirrhosis, hepatitis), a significant excess of the norm indicates malignant tumors. Cancer cells with a high degree of malignancy can acquire not only external resemblance to embryonic ones, but also functional features. A high titer of AFP accompanies poorly differentiated and embryonic tumors of the liver, ovaries, and prostate.

Neither the stage of the tumor nor its size or growth rate affect the degree of increase in AFP, that is, aggressive tumors may be accompanied by a less significant increase in the amount of this protein than more differentiated carcinomas. However, it has been proven that about half of patients with liver cancer have an increase in AFP as early as 1-3 months before the onset of tumor symptoms, which allows this analysis to be used as a screening in predisposed individuals.

When to determine AFP and how it is done

The main indications for determining the level of AFP in the blood serum are:

Suspicion of prenatal pathology: chromosomal diseases, brain development disorders, malformations of other organs.
Exclusion of hepatocellular carcinoma and diagnosis of liver metastases of other types of cancer.
Exclusion of tumors of the genital organs (teratoma, germinoma, poorly differentiated cancers).
Monitoring the effectiveness of anticancer therapy both before and after its initiation.

Determination of alpha-fetoprotein is carried out in liver diseases(cirrhosis, hepatitis) when there is a high risk of developing cancer. In such patients, the analysis may help early diagnosis of the neoplasm. It is worth noting that this test is not suitable for screening tumors in general due to non-specificity, so it is performed only when certain types of cancer are suspected.

During pregnancy an AFP test is indicated as a screening study conducted during the period of increase in its level in a woman - between 15 and 21 weeks. If at the beginning of pregnancy the patient underwent amniocentesis or a chorionic villus biopsy, then she also needs to control the level of AFP.

Absolute indications for the determination of AFP in a pregnant woman are:

consanguineous marriage;
The presence of genetically determined diseases on the part of parents and close relatives;
Children already in the family with genetic abnormalities;
First birth after 35 years of age;
Taking toxic drugs or X-ray examination of the expectant mother in the early stages of pregnancy.

Preparation for analysis

To determine the concentration of AFP, the preparation is extremely simple. Before the planned study, you need:

Refuse to take medication for 10-14 days;
On the eve of the analysis, do not eat fatty, fried and salty foods, do not drink alcohol, the last meal - no later than nine o'clock in the evening;
For a couple of days, limit strong physical activity, including heavy lifting;
In the morning, go for analysis on an empty stomach, but you can drink no more than a glass of water;
Smokers should not smoke at least half an hour before the test.

In the morning, about 10 ml of venous blood is taken from the subject, protein determination is carried out using the enzyme immunoassay method. The result may depend on some factors that both the specialist and the patient should be aware of:

The introduction of monoclonal antibodies and large doses of biotin change the level of the determined protein;
In representatives of the Negroid race, fetal protein is more than the average norm, in Mongoloids it is less;
Insulin-dependent diabetes mellitus in a future mother causes a decrease in AFP.

In the case of a pregnant woman, certain rules must be strictly observed. So, it is necessary to accurately determine the gestational age and the AFP level allowed during this period. Deviations from the norm in the absence of other signs of pathology on the part of the fetus cannot be an accurate sign of a defect, that is, false positive or false negative results are possible. On the other hand, protein fluctuations beyond normal values indicate an increased risk of pathology - premature birth, fetal malnutrition, etc.

Norm or pathology?

The norm of the concentration of alpha-fetoprotein in the blood depends on the age, gender, and the presence of pregnancy in a woman. In babies up to a year, it is higher than in adults, but gradually decreases, and girls have more of it than boys, and only after a one-year period, the concentration is set to the same values for both sexes. In adults, its amount should not exceed trace concentrations, otherwise we will talk about pathology. Expectant mothers are an exception, but their increase in AFP should also lie within certain limits.

During pregnancy, AFP is increased according to the gestational age. In the first trimester, its concentration is up to 15 International units per milliliter of blood, then gradually increases and reaches its maximum value by 32 weeks - 100-250 IU.

Table: AFP norms during pregnancy by week

In non-pregnant women, the following levels of AFP are considered normal:

Newborn boys (up to 1 month) - 0.5 - 13600 IU / ml;
Newborn girls - 0.5 - 15740 IU / ml;
Children under one year old: boys - up to 23.5 IU / ml, girls - up to 64.3 IU / ml;
In children after a year, adult men and non-pregnant women, the norm is the same - no more than 6.67 IU / ml.

graph of AFP levels depending on age and in various diseases

It is worth mentioning that the norm may depend on the method of determining the protein in the serum. The use of some automated analyzers suggests lower normal AFP values, which are usually reported to both the laboratory assistant and the attending physician.

If AFP is not normal...

Elevated blood AFP indicates the possible presence of a pathology, such as:

Neoplasms - hepatocellular carcinoma, testicular germ cell tumors, teratomas, liver metastases and some cancer localizations (stomach, lungs, mammary gland);
Non-tumor pathology of the liver - cirrhosis, inflammation, alcohol damage, previous surgical interventions on the liver (resection of the lobe, for example);
Violations of hemostasis and immunity (congenital immunodeficiencies, ataxia-telangiectasia);
Pathology in obstetrics - developmental anomalies, the threat of premature birth, multiple pregnancy.

In pregnant women, AFP is estimated based on the gestational age and data from other studies (ultrasound, amniocentesis). If there are signs of pathology on ultrasound, there is a high probability that AFP will also be changed. At the same time, an isolated increase in this protein is not yet a reason for panic, since the decoding of the analysis should be carried out in conjunction with other results of the examination of the expectant mother.

There are cases when a woman ignored elevated AFP and refused procedures such as amniocentesis or examination of chorionic villi, and subsequently a healthy baby was born. On the other hand, some defects may not cause fluctuations in this indicator. In any case, the study of AFP is included in the screening program during pregnancy, so it needs to be determined one way or another, and what to do then is decided by the woman together with the doctor of the antenatal clinic.

Elevated AFP along with those proven by ultrasound severe malformations often require termination of pregnancy, since the fetus may die before birth or be born non-viable. Due to the lack of specificity and a clearly established relationship between the amount of AFP and malformations, this indicator alone cannot be a reason for any conclusions. So, elevated AFP along with neural tube defects are observed in only 10% of pregnant women, the rest of the women give birth to healthy children.

Thus, AFP can be an important indicator and even one of the first signs of pathology, but by no means not the only, it should always be complemented by other studies.

In obstetrics, a blood test for AFP can indirectly indicate such fetal malformations How:

Deviations from the nervous system - absence of the brain, splitting of the vertebrae,;
Malformations of the urinary system - polycystic, kidney aplasia;
Umbilical hernia, defects in the anterior wall of the abdomen;
Violation of the formation of bone tissue, osteodysplasia;
Intrauterine teratoma.

A sign of trouble can be not only an increase, but also a decrease in the level of AFP, which is observed when:

Chromosomal pathology - Down syndrome, Edwards, Patau;
Intrauterine fetal death;
The presence of obesity in the expectant mother;
Violation of the formation of the placenta - cystic drift.

Based on the listed possible manifestations of changes in the level of AFP, it becomes clear that both raising and lowering it should be a reason for close attention to the patient and requires further examination.

With fluctuations in alpha-fetoprotein in men and non-pregnant women, the doctor, first of all, suspects cancer and liver pathology, therefore, additional examinations are carried out: a blood test for tumor markers, liver enzymes, ultrasound of the abdominal organs, consultations of narrow specialists (urologist, oncologist, hepatologist).

When the fact of tumor growth is confirmed, monitoring of the AFP level acquires a different meaning: a decrease in its amount indicates the effectiveness of the treatment, and an increase indicates the progression and possible metastasis of cancer.

Possibilities of using AFP

Attention to AFP is due not only as a marker for various diseases, but also the possibility of its use as a therapeutic agent. It is known that alpha-fetoprotein enhances the formation of fibroblasts in the connective tissue, stimulates apoptosis (programmed destruction of altered cells), prevents the binding of viral particles to lymphocytes and autoantibodies to body cells.

AFP is used as a drug for:

In addition, it has been noted that AFP preparations are able to improve potency, as well as have a beneficial effect on the skin, so they are used in cosmetology.

An example of an alpha-fetoprotein-based drug is alfetin, developed by Russian scientists, successfully passed clinical trials and already registered as a therapeutic agent. It has a good immunomodulatory effect, reduces the activity of autoimmune reactions, helps in the treatment of cancer, while the dose of chemotherapy drugs can be reduced.

Alfetin is made from fetal (fetal) AFP obtained from abortion serum. A diluted dry preparation is injected into the muscle or intravenously both in the process of treatment and for the prevention of many diseases.

Alpha-fetoprotein is an important health indicator therefore, when the doctor sees the need for analysis, you should not refuse. If the protein concentrations differ from the norm - this is not a reason to panic, after all, its quantity can speak not only of fetal defects or malignant tumors, but also of inflammatory processes and completely benign formations.

With the timely establishment of the fact of changes in AFP, in the arsenal of a specialist there will be not only additional high-precision examination methods, but also all kinds of methods for treating many diseases. The use of AFP-based drugs makes the treatment of a wide range of diseases more successful and gives hope for a cure for many patients.

AFP is an embryonic glycoprotein, normally produced by the cells of the yolk sac and the liver of the fetus, it performs mainly transport functions. Over time, the synthesis of AFP switches to the synthesis of albumin, therefore, in the blood serum of newborns, AFP is determined in very high concentrations, which gradually decrease and by the age of 8 months the child reaches the values of the adult norm. Since AFP crosses the placenta, it can be found in elevated concentrations in the mother's blood, reaching a maximum between 32 and 36 weeks of gestation. This serves as an important clinical indicator in monitoring the antenatal period.

The determination of AFP in children, men and non-pregnant women is highly sensitive to:

primary liver cancer;
germ cell tumors.

In adults, primary liver cancer in 90% of cases is represented by hepatocellular cancer, in children - hepatoblastoma. At a DN of 10–20 IU/mg, hepatoblastoma is always associated with elevated AFP values in 80–90% of cases and hepatocellular carcinoma. However, in most cases, hepatocellular cancer is diagnosed at an advanced stage, and the results of treatment are unsatisfactory. To improve early diagnosis, AFP-based screening programs are used among individuals with an increased risk of primary liver cancer (people with chronic active hepatitis B and / or C, liver cirrhosis of any etiology). These patients are 100 times more likely to develop primary liver cancer than the general population. The effectiveness of such screening in detecting operable tumors has been shown. An increase in the level of AFP during a dynamic examination of a patient with a high degree of probability means a malignant degeneration of the tissue, especially against the background of a steadily increasing activity of enzymes - alkaline phosphatase, γ-GT, AST, ALT. An increase in AFP can be recorded 2-10 months before the diagnosis of liver cancer.

Germinogenic tumors of newborns and infants are mainly represented by sacrococcygeal teratoid formations: AFP-negative teratomas and AFP-positive teratoblastomas. The marker of choice in the differential diagnosis of these neoplasms is AFP, since its sensitivity against teratoblastomas approaches 100%. Determination of AFP contributes to the choice of treatment tactics: AFP-negative teratomas require surgical treatment, while AFP-positive teratoblastomas require combined treatment.

Germinogenic tumors of adolescents and adults are distinguished by a variety of morphological forms and, in addition to AFP, they often produce hCG, so the simultaneous determination of both of these OM is a prerequisite. In the diagnosis of germ cell tumors with DU for AFP 10 IU / ml, for hCG 10 mIU / ml, the sensitivity of AFP is 60-80%, hCG - 40-60%. The combined determination of both of these OMs makes it possible to achieve a sensitivity of 86% for primary germ cell tumors and more than 90% for relapses of these tumors. Simultaneous determination of AFP and hCG in adolescents and adults helps to confirm the diagnosis both in the case of gonadal (ovaries, testicles) and extragonadal (mediastinal, retroperitoneal, central nervous system) germ cell tumors.

In boys and young men, OM measurement, along with testicular ultrasonography, may be useful in the differential diagnosis of epididymitis with painless swelling of one of the testicles.

Germ cell tumors are highly curable. Long-term remissions are observed in more than 90% of patients. The greatest risk of recurrence occurs in the first 2-3 years after treatment. AFP and hCG are the most accessible and most sensitive method for the early diagnosis of recurrent germ cell tumors. Practice shows that with normal values of OM, the recurrence of the disease can be excluded. An increase in one or both OM is associated with relapse in 100% of cases. The clinical significance of an increase in AFP and/or hCG levels is such that therapy should be started without waiting for clinical symptoms and based solely on the fact of an increase in OB level(s).

According to numerous clinical studies, AFP and hCG in germ cell tumors can act as independent prognostic factors. In accordance with the classification of germ cell tumors introduced in 1997, there are groups of patients with good (AFP< 1000, ХГЧ < 5000), умеренным (АФП 1000 – 10 000, ХГЧ 5000 – 50 000) и неблагоприятным (АФП >10,000, hCG> 50,000) is a prognosis, which contributes to the choice of adequate therapy.

When deciding on a therapeutic effect, the values of the concentrations of AFP and hCG take precedence over the histological conclusion. For example, an elevated AFP level in a patient with seminoma means that the regimen used for non-seminoma tumors should be used to treat the patient despite a histologically verified seminoma. Normalization of AFP and hCG levels confirms the effectiveness of therapy.

Indications for research

Diagnosis of primary liver cancer:
- the determination of AFP is indicated for newborns and infants in the detection of tumor formations in the liver;
- determination of AFP and ultrasound at a frequency of 1 every six months is recommended for patients with an increased risk of primary liver cancer.
Diagnosis and differential diagnosis of germ cell tumors:
- determination of AFP is indicated for newborns and infants with suspected teratoblastoma;
- simultaneous determination of AFP and hCG is indicated for:
- suspected ovarian cancer in girls and young women;
- suspected testicular cancer in boys and young men;
detection of tumors of unknown origin in the mediastinum or in the retroperitoneal space;
early diagnosis of recurrent germ cell tumors:
- regular simultaneous determination of AFP and hCG is indicated for patients who are without signs of disease after primary treatment with a frequency of: monthly during the first year, once every two months - for the second and once every three months for the third year from the start of treatment;
evaluation of the prognosis of the disease;
assessment of the effectiveness of therapy.

Material for research: Serum, cerebrospinal fluid.

Discrimination level: In men and non-pregnant women - 10 IU / ml

Increased values

Physiological reasons:
- pregnancy;
- hereditary due to increased expression of AFP.
Benign diseases:
- cirrhosis of the liver, chronic active hepatitis B and C (up to 100, less often up to 400 IU / ml);
- amoebic lesions of the liver.
Malignant neoplasms:
- primary liver cancer;
- germ cell tumors;
- liver metastasis from any primary tumor site (approximately 9% of cases, up to 100 IU / ml).

Diagnosis of all kinds of diseases involves the study of many different blood parameters, which make it possible to identify abnormalities in the body in adults and children, in addition, in fetal development in the fetus. One such test is AFP, which increases with developmental disabilities. In addition, it can determine the formation of certain types of tumors.

What it is?

The first protein alpha-fetoprotein (AFP) was discovered by American scientists in the serum of embryos, as well as in adults in the first half of the 20th century. It got its name because of its specificity for embryos.

To date, this indicator is of greatest interest in pregnant women, since serious pathologies and disorders in the development of the fetus can be determined by its concentration in the blood. Now let's figure out what the ACE blood test means and how to understand the results of the study.

Properties of AFP and its importance for the body

Alpha-fetoprotein is presented in the form of a special protein that is formed from the tissues of the embryo - the yolk sac, intestinal cells, hepatocytes. In the blood of an adult, only traces of it are found, and as for the fetus, it has a high density of AFP, which is determined by the functions that it performs. In the intrauterine fetus, this indicator is similar to albumin in adults, binds and transfers various nutrients, hormones, and performs the protective function of the baby's tissues from the immunity of his mother.

One of the main features of AFP is the ability to bind polyunsaturated fatty acids. Thanks to these components, the construction of cell membranes occurs, the synthesis of prostaglandins - biologically active substances, because they cannot be formed by the tissues of the embryo or in the mother's body. They can only come from the outside with food, therefore, in order to deliver them to their intended place, the presence of certain carrier proteins is necessary. What else does an AFP blood test mean?

It must be in the right concentration according to the timing of pregnancy, as it has a significant effect on the fetus. At the initial stages, when the fetus develops, AFP is produced with the help of the corpus luteum of the mother's ovary, as pregnancy develops, its concentration in the blood increases, reaching significant levels by the 13th week.

At the time of the birth of a child, his body produces albumin, which takes over the function of the fetal protein, and AFP levels begin to gradually decline in the first year of life. As for adults, for them only the detection of its traces is the norm, and with an increase in indicators, we can talk about serious pathologies. Thus, AFP is a marker that is necessary not only during pregnancy, but also to detect pathologies of internal organs in adults.

As noted earlier, the analysis for the determination of AFP is used as a screening indicator of the course of pregnancy without pathologies, which changes with various malformations and congenital syndromes. But it must be remembered that in order to obtain an accurate result about the presence or absence of pathology, it is necessary to produce a set of studies.

What else can AFP mean?

Consider what AFP in men means in a blood test.

A mild increase in alpha-fetoprotein in adults, as a rule, indicates abnormalities in the activity of the liver, with a significant excess of the norm, it is said about the development of malignant tumors.

The degree of increase in AFP is not affected by such indicators as the stage of the tumor, its size or growth rate, more precisely, tumors of an aggressive nature are accompanied by a less noticeable increase in the levels of this protein, which does not apply to more differentiated carcinomas. However, there are cases when about half of patients with liver cancer have elevated AFP already 1-3 months before the onset of the first symptoms of this disease. We learned what an ACE blood test means. How to prepare for this study?

Indications for analysis

To determine the level of AFP in the blood serum, you must have the following main indications:

The presence of suspicions of prenatal pathology, i.e. the presence of chromosomal diseases, brain developmental disorders, defects in other organs.

When hepatocellular carcinoma and the diagnosis of metastases of other types of liver cancer are excluded.

When genital tumors are excluded.

If necessary, control over the effectiveness of antitumor therapy from its beginning to the end.

If there is a high growth of cancer development in liver disease, an analysis is performed that determines the level of alpha-fetoprotein, which allows early detection of neoplasms. What does AFP mean in a blood test in women?

The test for AFP during pregnancy is a screening study that is carried out during the period of increase in its level in the expectant mother - between 15 and 21 weeks.

Mandatory determination of AFP in a pregnant woman is required in case of:

consanguineous marriage;
the presence of a genetic predisposition;
already existing in the family of children with congenital anomalies;
first birth at the age of over 35 years;
taking toxic drugs or x-ray examination of the expectant mother in the early stages of pregnancy.

How to prepare for the analysis?

To pass an analysis to determine the concentration of AFP, you must:

stop taking medications 10-14 days before the analysis;
you should refuse fatty, fried and salty foods, alcohol, do not eat after 21:00;
for two days, do not perform strong physical exertion, do not lift weights;
the analysis is taken on an empty stomach, only the use of no more than one glass of water is permissible;
It is forbidden for smokers to smoke half an hour before the analysis.

During an AFP blood test, approximately 10 ml of blood is taken from a patient from a vein. The protein is determined using the enzyme immunoassay method.

Norm and pathology in pregnant women

Normative indicators of the level of alpha-fetoprotein density depend on many factors: age, gender, the presence of pregnancy in a woman. In children under one year old, this level is higher than in an adult, but with age it begins to decrease, in girls it is higher. Upon reaching the age of one, both in boys and girls, the level of AFP concentration in a blood test (which means during pregnancy, interesting to many) becomes the same.

During pregnancy, the level of AFP should correspond to gestational age. Let's look at the norms for the ratio of gestational age and AFP levels in the blood: in the first 12 weeks = less than 15 U / ml, and in the last weeks = 100-250 U / ml.

Everyone else

As for non-pregnant women, men and children, their AFP level is as follows: in boys up to 1 month - 0.5 - 13600 IU / ml; in girls up to 1 month - 0.5 - 15740 IU / ml; in boys up to a year - up to 23.5 IU / ml; in girls up to a year - up to 64.3 IU / ml; after a year in children, as well as in adult women who are not in position and in men - no more than 6.67 IU / ml.

It must be borne in mind that the indicators of the AFP norm may depend on the methods for determining the protein in the blood serum. When using certain automatic analyzers, there may be lower AFP values, but both the laboratory assistant and the attending physician should always warn about this.

What does AFP mean in a blood test?

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With elevated blood AFP, the presence of pathologies is possible:

hepatocellular cancer;
germ cell tumors of the testicles;
teratoma;
metastatic liver disease;
liver diseases - cirrhosis, inflammation, alcohol damage, surgical intervention;
congenital immunodeficiency, ataxia-telangiectasia;
pathologies during pregnancy - malformations, the likelihood of premature birth, multiple pregnancy.

During pregnancy, the determination of AFP can reveal many pathologies of fetal development. These are deviations in the development of the nervous system, such as lack of a brain, separation of the vertebrae, hydrocephalus; from the urinary system - polycystic, lack of a kidney; hernia of the navel, deviations of the anterior wall of the abdomen; abnormal bone formation, osteodysplasia; intrauterine teratoma. What does AFP mean in a blood test (108.9 value, for example)?

Not only an elevated level of AFP in the blood is a sign of the presence of abnormalities, but also a low one, which indicates the presence of chromosomal abnormalities - Down syndrome, Edwards, Patau; frozen fetus in utero; obesity in a pregnant woman; developmental disorders of the placenta - hydatidiform mole.

conclusions

Thus, having considered all kinds of pathologies associated with deviations from the normal level of AFP in the blood, we conclude that both an increase and a decrease in the level of AFP is a reason for further monitoring of the patient's health and entails the need for further examination.

When deviations from the normal level are found in adults, this means that there is a possibility of developing an oncological disease, as well as liver pathology. In this situation, additional examinations are required, which consist of taking a blood test for tumor markers, liver enzymes, and undergoing an ultrasound scan of internal organs. You should also consult with narrow specialists (urologist, oncologist, hepatologist).

We looked at what an AFP blood test means.

Throughout your life, you often have to deal with various kinds of laboratory research. And it's not even about the potential diseases that they are able to detect. No, pregnant women become the most frequent guests of the laboratory, because general tests are not enough for a complete examination and control of the pregnant state.

Naturally, this does not mean that if you had not conceived a child, you would not even have guessed about the existence of AFP. Proof of this are the numerous male patients and young children who were given a disappointing diagnosis, turning alpha-fetoprotein into a tumor marker. Although in this case there is a “false alarm”, you just need to familiarize yourself with the generally accepted norms for the concentration of the declared protein and the possible nuances of its fluctuation.

AFP (alpha-fetoprotein) is a kind of protein that can be produced by internal organs, in particular the liver and gastrointestinal tract, of a very tiny embryo. That is why for a pregnant woman this indicator is the norm and must correspond to the stated period. Otherwise, we will talk about possible pathologies of the fetus, often not even compatible with life.

In a non-pregnant state, the protein secretes the corpus luteum of the ovaries, after conception, the embryo itself, from about 5-6 weeks of an interesting position.

It should be understood that this is not only a guideline for the normal development of the baby, but also a kind of “shield” from maternal immunity, which often strives to reject a foreign body. And the longer the period, the more important the concentration of AFP in her body. The latter is measured in MoM(multiples of median - the multiplicity of the median). This is especially important again during pregnancy, since there is a need for constant monitoring of alpha-fetoprotein throughout all three trimesters and regular comparison of the obtained indicators.

No less necessary is the examination of men / non-pregnant women / children for AFP levels, if there is a possibility of confirming an oncological disease, malignant neoplasms, cirrhosis of the liver or its insufficient functionality, viral hepatitis, etc.

AFP norm

In order to analyze the norms of the concentration of alpha-fetoprotein in the blood of a patient / patient, first the latter should be divided into two groups: men/non-pregnant women/children and pregnant women.

So, what role does AFP play for the first group, and what quantitative indicator should not cause alarm in it?

Many medical sources indicate the number 10 (MoM) as the limit of normal, although the optimal index is still considered 0-2.5 MoM. At the same time, any of its fluctuations should be taken into account, since at stake, most often, is the diagnosis of "cancer": of the gastrointestinal tract, liver, pulmonary system, testicles. No less comforting will be the diagnosis of cirrhosis of the liver or viral hepatitis.

For pregnant women, on the contrary, these figures should gradually increase, starting from the middle of the first trimester, reaching a maximum at 32-36 weeks (from 11 to 250 MoM). Do not forget that this is not a general blood test and you do not need to take it so often. But be prepared for the fact that it will become part of all mandatory screenings (the so-called "triple tests"). And since each laboratory has its own standards and designations, it is better to entrust the interpretation of the results to your doctor.

alpha fetoprotein during pregnancy

Let us consider in more detail the indicators of AFP during pregnancy and its role in a comprehensive examination of the fetus. Particular emphasis should be placed on the word “complex”, since the alpha-fetoprotein indicators themselves do not carry the necessary information. Accordingly, there can be no question of diagnosing an unborn child.

Therefore, recommended screenings should be taken, which will not only indicate the required amount of MoM, but also highlight the complete picture of hCG and free estriol. The final "stroke" of the study will be ultrasonography to confirm the exact gestational age and further analysis of the condition and development of the fetus.

When all the constituent parts of the study are carried out and the AFP level turns out to be too high or low for the declared period, it will be possible to draw conclusions about possible pathologies or malformations of the embryo, necessarily making an allowance for multiple pregnancy.

So too high levels of alpha-fetoprotein testify to:

Liver failure in the fetus or necrosis of this organ.
Pathology of the neural tube.
Underdevelopment of the genitourinary system.
Probability of umbilical hernia.

Low AFP talking about:

Down Syndrome.
Frozen / false pregnancy, anembryony.
Edwards syndrome.
Serious pathologies of fetal development.

AFP level in women

If pregnant women are presented with the need to be tested for the concentration of alpha-fetoprotein, which is also amenable to careful monitoring by the leading obstetrician-gynecologist, then what about those who do not carry a child under their hearts, but clearly have problems with the level of the mentioned protein.

In such cases, the first symptoms appear some diseases, especially if it is oncology. The next step will be a clinical blood test, in the results of which the number of leukocytes / platelets, as well as the level of ESR, will not correspond to the norm.

Only after that it will be necessary to pass the analysis on tumor marker, which is AFP in the absence of pregnancy. Its excess of 11 MoM will show the likelihood of oncology of the female organs, mammary glands, colon or pancreas. The necessary research is also carried out in case of renal failure, liver metastases or viral hepatitis.

In men

A similar situation applies to the stronger sex, since an increased level of alpha-fetoprotein in men is no less frequent a “guest”. Under the guise of an increase, we mean raising the quantitative indicator above the 10 MoM mark.

Given that a high level of AFP is a signal of the possible progression of cancer, its use is often observed as a tumor marker. The latter is especially significant in antitumor activity, trying to destroy malignant cells in the gastrointestinal tract, liver, and lungs.

But, as practice suggests, with elevated AFP in men, oncology is most often found in the genitourinary system, in particular, the testicles. With a slight excess norms of protein concentration (up to 15-18 MoM) mainly diagnose liver cirrhosis due to chronic alcoholism.

The child has

Since alpha-fetoprotein is an embryonic glycoprotein and is produced by the fetal liver (or the corpus luteum of the ovary until the fifth week of pregnancy), a high AFP level in a newborn. This despite the fact that the highest concentration was to be reached at the end of the third trimester (up to 250 MoM).

After being born for quite a long time, the level of alpha-fetoprotein may differ from the norm of "adult" indicators, but by the age of 8-12 months it gradually decreases and does not exceed 9-10 MoM.

If the child is already over a year old, and the level of the mentioned protein is much higher than normal or even increases, an urgent additional examination will be required to rule out oncology and other serious diseases.