PAPP-A test – indications, course, results. Reimbursement of the PAPP-A test

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The decision about having a child is not the easiest one. Until 20 years ago, the average age of a woman who became pregnant for the first time was 24. Now in Poland, the average age of a mother is almost 30 years. Spanish, Italian and Swedish women decide for later motherhood. However, later motherhood is associated with a higher risk of genetic diseases in the baby. One of the prenatal diagnostic tests in their case is the PAPP-A test.

PAPP-A test – what is it?

The PAPP-A test, i.e. a double test, is a biochemical test that allows to assess the level of PAPP-A protein and free beta hCG in a future mother. For this purpose, blood is taken from the ulnar vein from the pregnant woman, which is then analyzed.

The PAPP-A test is usually preceded by an ultrasound examination, which allows to determine the so-called nuchal translucency of the fetus and its anatomical structure. When the PAPP-A test and ultrasound are combined, we speak of composite test.

The PAPP-A test must be performed between weeks 11,6 and 13 + 6 of pregnancy. It is also very important that during this period the fetal parietal length is between 45 and 84 mm. Then the best visible is the translucency of the nape, i.e. the amount of fluid that is under the skin tissue on the child’s neck. It is on this basis that the specialist assesses the risk of genetic defects.

Read: Prenatal testing. How much do they cost and when are they refunded?

PAPP-A test – indications for the test

The PAPP-A test belongs to the group of non-invasive prenatal tests. This means that its conduct is not associated with any risk for both the mother and the unborn child. However, the PAPP-A test is not always ordered by the attending physician. Meanwhile, many specialists believe that it should be performed even when the ultrasound image is correct.

The test should be performed by every woman who belongs to the so-called risk groups. We are talking about all pregnant women who:

1. are over 35 years old,
2. in the past, they gave birth to a child with a genetic defect, metabolic disease or a defect of the central nervous system,
3. there were genetic defects in their family or in the family of the child’s father,
4. had previously performed pregnancy ultrasound examinations, and their results turned out to be alarming for the doctor performing them.

What can be diagnosed on the basis of the PAPP-A test?

You should know that the PAPP-A test is not used to diagnose a child’s genetic disease. Its task is to determine the child’s risk of trisomy, i.e. chromosomal defects in the child’s DNA. These disadvantages consist in the presence of an extra chromosome in a specific pair of chromosomes.

The PAPP-A test is able to assess the risk of:

1. Trisomiichromosome 13, known as teamPatau – this defect is associated with a very low birth weight of the fetus, heart and kidney defects, skin defects, abnormal craniofacial development and reduced muscle tone. It is estimated that 90-95 percent. children born with diagnosed Pataunie syndrome reach the age of 1. This defect occurs in 1 in 8-12 thousand. births.
2. Trisomiichromosome 18, known as Edwards syndrome — this defect is manifested by low birth weight, numerous head deformities, abnormal functioning of the kidneys, lungs, heart and other internal organs. As in the case of the Patau syndrome, 1 percent do not live until the age of 95. born children.
3. Trisomiichromosome 21, known as down syndrome – is the most common genetic disease associated with an abnormal number of chromosomes in a child. It is characterized by a child’s mental retardation, immunodeficiency, muscle laxity and a characteristic appearance. Currently, people with Down syndrome live up to the age of 49. The estimated risk of Down’s syndrome at the age of 25 is 1: 1250, for a woman over 35, 1: 350, and for a mother over 45, 1:28. This means that 1 in 28 babies born to a woman aged 45 will be born with Down syndrome.

The PAPP-A test is approximately 90% effective in detecting Down’s syndrome and other genetic defects. This means that it indicates an increased risk in 9 out of 10 children who are sick. Only new generation prenatal screening tests, such as the NIFTY test, are more effective.

See: The most common genetic diseases. How are they made?

Incorrect PAPP-A test result – what next?

In Down’s syndrome, maternal PAPP-A protein in blood is usually lowered and beta hCG levels are above normal. In the case of Edwards-Patau’s syndrome, both substances are below normal.

It is worth remembering, however, that the final diagnosis can only be performed by the doctor in charge of the pregnancy, who will take into account all the factors and the results of the tests performed so far.

If the PAPP-A test result worries him, he will certainly order additional, invasive prenatal tests, such as amniocentesis. It is the most frequently performed invasive genetic test due to its wide spectrum and relatively low risk of complications. During amniocentesis, the doctor uses a long needle to puncture the abdominal wall of the pregnant woman and take a sample of the amniotic fluid. This is subject to examination, on the basis of which the result is developed.

If the amniocentesis result is also abnormal, we can be almost completely sure that the baby is sick. Early diagnosis of the disease allows parents to properly prepare for the birth of a sick child. This means getting to know the disease and adapting your current life to the needs of a child with a genetic defect.

PAPP-A test – reimbursement

The PAPP-A test is reimbursed for women over 35 and those who previously gave birth to a child with a genetic defect. The PAPP-A test is also performed by the National Health Fund in the case of women in whose families children were born with genetic defects. The same is true of the child’s father’s family.

If a woman does not meet the above conditions, she does not belong to the so-called risk groups. Then he can perform the PAPP-A test on his own. Its cost is about PLN 250-300.