Alpha fetoprotein. AFP analysis during pregnancy and in other cases.

Reference values

For children, men and non-pregnant women, normal values ​​are presented in the table.

For pregnant women, depending on the stage of pregnancy, normal values ​​are presented in the table.

Alpha-fetoprotein refers to the so-called embryonic proteins, which are synthesized by embryonic cells.
AFP performs many important functions, ensuring the full development of the fetus. Alpha-fetoprotein enters the blood of a pregnant woman through the placenta (the “baby place” that forms during pregnancy and connects the mother and fetus, providing the baby with essential nutrients) and from the amniotic fluid (amniotic fluid, which plays an important role in the metabolism of nutrients and fetal protection). Accordingly, with an increase in the concentration of fetal alpha-fetoprotein, its values ​​in the mother’s blood increase, increasing from the 10th week of pregnancy and reaching maximum values ​​by the 32-34th week. Alpha-fetoprotein testing in pregnant women is carried out as part of a “triple test” together with hCG (human chorionic gonadotropin) and E3 (free estriol) in the second trimester of pregnancy (between 15 and 20 weeks) to identify the risk of abnormal development of the fetus.

An embryonic protein that indicates the condition of the fetus during pregnancy and is a tumor marker for an adult.

Synonyms Russian

AFP.

English synonyms

Alfa-Fetoprotein, AFP, Maternal Serum Alpha-Fetoprotein (MS-AFP), AFP Tumor Marker.

Research method

Solid-phase chemiluminescent enzyme-linked immunosorbent assay (“sandwich” method).

Determination range: 0.5 - 50000 IU/ml.

Units

IU/ml (international unit per milliliter).

What biomaterial can be used for research?

Venous blood.

How to properly prepare for research?

• Do not smoke for 30 minutes before the test.

General information about the study

Alpha-fetoprotein is a glycoprotein that is produced in the fetal yolk sac, liver and intestinal epithelium of the fetus. The molecular weight of the protein is about 70,000 daltons, its half-life is 5-7 days. In the fetal body, it performs the functions of adult albumin: it transports certain substances necessary for the development of the fetus, binds estrogens, limiting their effect on the developing body, and protects against the negative effects of the mother’s immune system.

Alpha-fetoprotein takes an active part in the full development of the fetus, and its level should correspond to gestational age (the age of the fetus from the moment of fertilization). The maximum content of this protein in the blood and amniotic fluid of the fetus is observed at the 13th week, and in the mother’s blood it gradually increases from the 10th week of pregnancy and reaches a maximum at 30-32 weeks. 8-12 months after birth, the level of AFP in the child’s blood decreases to a trace amount, as in adults.

Alpha-fetoprotein enters the mother's body through the placenta. Its level depends on the condition of the gastrointestinal tract, fetal kidneys and placental barrier. In this regard, AFP is used as a nonspecific marker of fetal condition and obstetric pathology. Combined tests for AFP, human chorionic gonadotropin and estriol (the so-called triple test) at 15-20 weeks of pregnancy are used to check the fetus for developmental defects and chromosomal abnormalities, but are not absolute indicators of pathology or normal fetal development. In this case, it is very important to know exactly the gestational age of the fetus, since the level of AFP in the blood differs at different weeks of pregnancy.

In the adult body, alpha-fetoprotein is absent or found in minimal quantities. A moderate increase in its level can be caused by liver pathology, and a significant increase can be caused by a poorly differentiated tumor - this is due to the fact that some cancerous tumors acquire the properties of embryonic tissues and, accordingly, the ability to synthesize proteins that are characteristic of the early stages of development of the body. A sharp increase in AFP is mainly detected in cancer of the liver and gonads.

In primary hepatocellular carcinoma, an increase in AFP in half of the patients can be detected 1-3 months before the clinical manifestations of the disease. Although the size of the tumor, the intensity of growth, the stage of the process and the degree of malignancy are not proportional to the amount of alpha-fetoprotein in the blood. With progressive germ cell nonseminoma (tumor of the gonads), determining the level of AFP and human chorionic gonadotropin is important for assessing the chances of survival of patients.

What is the research used for?

• For prenatal diagnosis of pathologies of fetal development: disorders of the neural tube, anencephaly (severe developmental defect in which the fetus is missing part of the brain), chromosomal abnormalities.
• To detect primary hepatocellular carcinoma (liver cancer).
• To detect testicular teratoblastoma (germ cell nonseminoma).
• For the diagnosis of poorly differentiated tumors.
• For the diagnosis of metastases of tumors of various localizations in the liver.
• To evaluate the effectiveness of treatment for certain cancers and to monitor their course.

When is the study scheduled?

• When examining a patient with a high risk of developing a tumor (liver cirrhosis, chronic hepatitis, alpha-antitrypsin deficiency).
• If tumor metastasis to the liver is suspected.
• When examining a patient with a neoplasm of the gonads.
• Before, during and after treatment for certain cancers.
• When monitoring the condition in the postoperative period of patients who had a tumor removed.
• In the second trimester of pregnancy (between the 15th and 21st weeks of gestation).
• When examining pregnant women who underwent amniocentesis and chorionic villus sampling in early pregnancy.

What do the results mean?

Reference values

Causes of increased alpha-fetoprotein levels

Oncological diseases:

• hepatocellular carcinoma (liver cancer) (in 70-95% of cases),
• germ cell nonseminoma (testicular cancer),
• liver metastases (in 9%),
• tumors of other localizations (lung, intestinal, stomach, kidney, breast, pancreas cancer),
• embryonal tumors (teratomas).

Other pathological conditions:

• acute or chronic active hepatitis (moderate and short-term increase in the rate),
• primary biliary cirrhosis,
• alcoholic liver disease,
• liver injury (or surgery),
• congenital tyrosinemia,
• ataxia-telangiectasia,
• Wiskott–Aldrich syndrome.

Obstetric pathology:

• fetal neural tube defects (spina bifida, anecephaly) (80-90%),

• developmental disorder of the urinary system (congenital nephrosis, polycystic kidney disease, absence of a kidney, obstruction),
• atresia of the esophagus or intestines,
• umbilical hernia,
• gastroschisis (defect of the anterior abdominal wall),
• fetal teratoma,
• cystic hygroma,
• hydrocephalus,
• fetal distress,
• threatened abortion,
• pathology of the placenta,
• multiple pregnancy,
• incomplete osteogenesis.

Reasons for low alpha-fetoprotein levels:

• Down syndrome (trisomy 21),
• Edwards syndrome (trisomy 18 chromosome),
• Patau syndrome (trisomy 13 chromosome),
• intrauterine fetal death,
• hydatidiform mole,
• pregnancy obesity.

A decrease in AFP levels after tumor removal is considered a favorable sign and indicates the effectiveness of treatment.

What can influence the result?

• The patient's use of monoclonal antibody medications may change the test result.
• Among representatives of the Negroid race, maternal AFP is 10-15% higher than the average, while among Mongoloids it is lower.
• Insulin-dependent diabetes leads to a decrease in AFP in the blood of a pregnant woman.

Important Notes

• To use the test in diagnosing obstetric pathology, it is necessary to accurately know the gestational age of the fetus. The level of alpha-fetoprotein alone cannot serve as a criterion for diagnosing fetal development disorders. If deviations in ACE levels are detected, it is necessary to comprehensively examine the pregnant woman using ultrasound diagnostics and other laboratory methods.
• If the AFP level is elevated in a pregnant woman and there are no pathological changes on ultrasound and amniocentesis, it is necessary to keep in mind the high likelihood of developing disorders (for example, premature birth, low birth weight of the child, fetal death).
• The use of AFP for cancer screening in the general population is not recommended.
• Patients taking high doses of biotin (>5 mg/day) should be tested no earlier than 8 hours after taking the drug.

Reasons for the decrease in alpha-fetoprotein in the blood of pregnant women

• Down syndrome in the fetus,
• delayed fetal development,
• fetal death
• false pregnancy.

AFP is used as a tumor marker in adult men and non-pregnant women.
As the tumor process develops, cancer cells begin to synthesize alpha-fetoprotein, so an increase in its concentration in the blood indicates the presence of a malignant neoplasm. Alpha-fetoprotein was first described as a human tumor-associated protein in 1964. It was then discovered that elevations of alpha-fetoprotein above the values ​​typically found in healthy individuals occur in several malignant diseases such as testicular cancer, liver cancer (primary hepatocellular carcinoma), with metastases of other tumors to the liver.

Patients with liver cirrhosis (a disorder of the liver structure, manifested by functional failure), chronic hepatitis B and C are at risk of developing liver cancer. The determination of alpha-fetoprotein in them is of great practical importance.

The level of alpha-fetoprotein in liver cancer and testicular cancer well reflects the dynamics of therapy. A significant decrease in alpha-fetoprotein after chemotherapy indicates the effectiveness of treatment.

Sources:

1. Rodriguez-Diaz JL, Rosas-Camargo V, Vega-Vega O, Morales-Espinosa D, Mendez-Reguera A, Martínez-Tlahuel JL, et al. Clinical and pathological factors associated with the development of hepatocellular carcinoma in patients with hepatitis virus-related cirrhosis: a long-term follow-up study. Clin Oncol (R Coll Radiol) 2007; 19:197-203.
2. Chereshnev V.A., Rodionov S.Yu., Cherkasov V.A., Malyutina N.N., Orlov O.A. Alpha fetoprotein. Ekaterinburg: Ural Branch of the Russian Academy of Sciences, 2004. 376 p.
3. N. Salesi, B. Di Cocco, F. Alghisi, F. Calabretta, G. Bossone. Testis cancer markers. Clinical use. Minerva Med. 2002 Oct; 93(5):365-9.

What may affect the results of the study?

The main reason why AFP levels may be elevated in women is pregnancy, which the patient may not yet be aware of. Therefore, before taking the test, women should make sure that they are not pregnant (take a test), and also discuss with the doctor the most suitable day for the test depending on the menstrual cycle. Alpha-fetoprotein levels may vary in nursing mothers; the optimal time for testing and individual preparation advice will also be provided by the doctor who ordered the test.

In addition, changes in the level of tumor markers in the blood can be influenced by certain diseases (Wiskott-Aldrich syndrome, congenital tyrosinemia, ataxia-telangiectasia), taking medications (based on monoclonal antibodies, Biotin), and belonging to the Negroid race.

What does alphafetoprotein tumor marker show?

Checking the alpha-fetoprotein tumor marker is prescribed in the following cases:

• Comprehensive diagnostics of the pelvic and abdominal organs in case of frequent malaise due to the absence of adequate causes.
• Monitoring the course of pregnancy in case of suspected pathologies in the fetus based on the results of other tests.
• When there is a family history of cancer.
• Monitoring the effectiveness of treatment and recovery after a course of procedures.
• Monitoring the process of metastasis or confirming its absence.
• Visiting cancer clinics is a thing of the past.
• Chronic alcoholism.
• Chronic hepatitis.

Everyone does not need to be tested for this tumor marker. Only a doctor can determine who needs it.

To pass the test, you need to properly prepare for this process. There are no special requirements. The main condition is to donate blood on an empty stomach in the morning from 8 to 11-12 hours. It is advisable to follow a diet, and 12 hours before the test, exclude all food and drink, except clean water without gas. Water is also acceptable on the day of blood collection.

3-4 days before, you need to stop taking medications in consultation with your doctor, stop drinking alcohol and smoking. Significant physical activity and stress are undesirable.

Before going for analysis, you should not undergo massage or any medical examinations.

Compliance with the rules and requirements for preparing for analysis increases the accuracy of the research results.

3.How to prepare and how is the analysis carried out?

How to prepare for an AFP test

You do not need to prepare before your AFP test.

Pregnant women are weighed because... Test results also depend on weight. They also vary by age, gestational age, and race.

How is AFP analysis performed?

An AFP test is performed after taking blood from a vein. Blood sampling from a vein is carried out according to a standard procedure.

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About the disease

As a rule, the precursors of liver cancer are chronic diseases of the organ:

• Hepatitis;
• Cirrhosis;
• Hepatoses;
• Parasitic infestations.

The following precancerous diseases contribute to pathological changes in the liver:

• Increased bilirubin;
• Elevated liver transaminases;
• Manifestation of “sign” symptoms, for example, chronic weakness, fatigue, heaviness in the localization of the liver, jaundice, etc.

It is important for people at risk to periodically undergo medical examinations, take appropriate tests, and participate in diagnostic activities for the purpose of early detection of a malignant tumor.

You need to know that the initial stage of liver cancer is often asymptomatic or simply invisible against the background of precancerous diseases.

Already at stages 2-3, symptoms appear:

• Rapid weight loss;
• Heaviness in the area of ​​the right hypochondrium and pain;
• Increased liver size;
• Jaundice;
• Ascites.

In addition, biochemical tests show a sharp increase in liver enzymes and bilirubin.

Indications

The analysis is indicated for patients included in the “risk group” for the development of primary oncology:

• Those suffering from chronic hepatitis, cirrhosis and some other diseases that increase the risk of liver cancer;
• The presence of another type of oncology, if there is a suspicion of metastases in the organ.
• When diagnosing the primary form of liver oncology in order to monitor the effectiveness of therapy, the development of the disease, and the occurrence of its relapses.
• During the initial examination procedure in pregnant women and some poorly differentiated tumors.

PD-L1 Expression Analysis

The material for analysis is venous blood, which is taken on an empty stomach. 30 minutes before donating blood, the patient should not smoke or experience high physical activity.

Tumor markers

Tumor markers are unique chemicals found in the blood and urine of patients with cancer. Once upon a time, tumor markers were considered the main means of early diagnosis of cancer, but now it has become clear that this is not so.

Practical experience in the use of tumor markers has shown that their presence and increase may be the result of other pathologies rather than cancer. And vice versa, they showed a negative result in cases of diagnosing oncology.

Today, tumor markers are used during the initial examination. In most cases, such an analysis is secondary; it is an additional diagnosis, which subsequently helps to monitor treatment, predict relapses, and the development of the disease.

Indications for examination

Knowing that the AFP tumor marker is a protein formation that helps to identify a dangerous pathology long before its clinical detection and the manifestation of any symptoms, in some cases you should undergo an examination.
The main indications for testing for cancer markers are:

• Genetic predisposition to cancer.
• Chronic liver diseases, hepatitis of all types, symptoms of cirrhosis.
• Suspicions of the presence of seals in the body.
• Precancerous conditions.
• Detected benign tumors with a high risk of degeneration into malignant ones.
• Monitoring the progress of treatment and after its completion in order to predict relapse.
• After removal of the pathological neoplasm.
• To predict the risk of metastasis of harmful pathologies.

It is also necessary for pregnant women to find out what the AFP tumor marker shows. In this case, the typical situation is when its level is high. This is due to the fact that the embryo is perceived by the body as a foreign body, and it tries to defend itself. But if Alpha protein is reduced, pathologies in the fetus should be suspected, for example, Down syndrome, trisomy and many others. At the same time, exceeding an already high level of protein also indicates problems with the development of the fetus, including the risk of intrauterine death.

What is an AFP marker?

Alpha-fetoprotein tumor marker (Alpha-fetoprotein) is a specific protein compound produced by the cells of the yellow sac in the body of the embryo. Its maximum level is reached at 34 weeks of pregnancy, after which it gradually decreases. By the first year of a baby’s life, the amount of alpha protein stabilizes and is the same as that of a healthy adult.

In the body of adults, the tumor marker is produced mainly by liver cells, which is why it is called a liver marker and an analysis is prescribed to detect it if liver cancer, hepatitis and other complex diseases are suspected. Also, the tumor marker alphafetoprotein is also informative in diagnosing possible oncology of the testicles in men, ovaries in women, and pancreas. Accordingly, it refers to the markers of the listed organs.

Testing for only one tumor marker is not sufficient to make a diagnosis. Therefore, if the reaction is positive, do not panic. It could just be inflammation!

Please note that this protein is sensitive not only to neoplasms in adults and pathologies in the embryo, but also to inflammation and various dysfunctions of these organs.