Alpha-fetoprotein, α-fetoprotein (AFP) is a fetal protein that under physiological conditions is secreted by the fetal liver cells and the embryonic yolk sac. Its concentration increases during physiological pregnancy, but also in pathological conditions related to pregnancy and beyond. What is the correct alpha-fetoprotein concentration?

Alpha-fetoprotein (AFP)is a fetal protein, the concentration of which increases during physiological pregnancy, but also in pathological conditions related to pregnancy and beyond - in neoplasms, tumors primary and metastatic liver disease, hepatitis and cirrhosis, intestinal polyposis, Crohn's disease, tyrosinemia (genetic disease), hereditary condition of persistence of high AFP. Correctly, in adults it is<40ug/l, u kobiet w ciąży jej stężenie wzrasta w zależności od zaawansowania ciąży.

AFP - meaning in pregnancy

Normally, the concentration of fetal AFP increases from the 10th week of pregnancy and reaches its highest values ​​before the 18th week of pregnancy, and then gradually decreases. Changes in the concentration of AFP in the amniotic fluid are parallel. In the mother's blood, the increase in alpha-fetoprotein concentration appears with some delay - this protein crosses the placenta and reaches its highest values ​​between 32 and 36 weeks of pregnancy.

The AFP study reflects the child's condition:

Increased concentration of AFP in the mother's serumoccurs in malformations of the child, especially of the nervous system, in life-threatening conditions and in a dead pregnancy. On the other hand, it may be the result of a multiple pregnancy.

Reduced levels of AFPoccur in Down's syndrome. In the first and second trimesters of pregnancy, screening tests are performed, consisting of an ultrasound assessment of the fetus, measurement of the concentration of PAPP-A and B-hCG, and a triple test. In the second trimester of pregnancy, between 15 and 20 weeks, for prenatal diagnosis, AFP is measured in a triple test in addition to free estriol and the B-hCG subunit. These tests look for the risk of trisomy 21 (Down syndrome) and open neural tube defects in the fetus. It is the most precise test, its sensitivity, according to some authors, exceeds 90%.

AFP in Oncology

The concentration of alpha-fetoprotein is important in oncology. Often, levels of this protein are increased in liver cancer and in other types of cancermalignant - certain types of malignant tumors of the testes and ovaries (the so-called embryonic carcinomas), in lymphomas, kidney cancer, colorectal cancer, lung cancer and gastric cancer, neuroblastoma and yolk sac cancer.

AFP levels are increased in 90% of patients with hepatocellular carcinoma (primary cancer of the liver cells), increasing with tumor growth and decreasing with successful treatment. The level of this protein in the blood, upon diagnosis, may increase>500 µg / L (it may also happen that these values ​​are within the normal range - not all patients have an increase in AFP). On the other hand, lower values ​​may appear in secondary liver cancer, i.e. in the metastasis of another type of cancer to this organ. Increased, but less than 500 µg / L values ​​may also be due to non-neoplastic damage to liver cells.

Elevated levels of AFP in the blood are observed in patients with acute hepatitis B and hepatitis C, chronic active hepatitis, cirrhosis and alcoholic cirrhosis. In patients with chronic liver disease such as cirrhosis or chronic hepatitis B, it is recommended that AFP testing be performed at regular intervals as there is an increased risk of developing hepatocellular carcinoma for the rest of their lives. AFP testing is ordered for the purpose of: diagnosing, monitoring the effectiveness of treatment and recurrence of liver tumors, ovarian and testicular cancers, and the systematic follow-up of patients with chronic liver disease for the presence of hepatocellular carcinoma or another type of liver cancer.

Does blood alpha-fetoprotein testing require preparation?

Testing the level of AFP protein does not require any preparation, does not cause complications, and there are no contraindications for it. It consists in drawing blood after puncturing a superficial vein, usually the ulnar fossa.

What are the correct alpha-fetoprotein values?

The correct AFP value should not exceed 15 ng / ml. Pregnant women in the first trimester - 10 µg / l, in the second trimester - 300 µg / l, in the third trimester - 500 µg / l.

Category:

Pregnant examinations