2060. Package #25 (Prenatal screening II trimester: AFP, β-HCG, E3)

Package No. 25 (Second Trimester Prenatal Screening: AFP, β-hCG, E3) – noninvasive biochemical screening during the second trimester of pregnancy. It measures AFP, free β-hCG, and estriol levels to assess the risk of fetal chromosomal abnormalities (21, 18, 13) and neural tube defects. The optimal time is 16-18 weeks.

Package No. 25 (Second Trimester Prenatal Screening: AFP, β-hCG, E3) is a comprehensive non-invasive prenatal test used in the second trimester of pregnancy to assess the risk of fetal chromosomal abnormalities and congenital malformations. It is also known as the ‘triple test’.

It includes three key biochemical markers:

• AFP (alpha-fetoprotein) – a marker of neural tube defects;
• β-hCG (free beta subunit of human chorionic gonadotropin) – an indicator of the risk of trisomies;
• E3 (free estriol) – a placental estrogen reflecting the state of the fetoplacental complex.

These markers is aimed:

• to identify the risk of trisomies 21 (Down syndrome), 18 (Edwards syndrome), and 13 (Patau syndrome);
• to suspect anencephaly, spina bifida, omphalocele, and other neural tube or abdominal wall malformations;
• to assess the functional state of the placenta.

Package No. 25 (Second Trimester Prenatal Screening: AFP, β-hCG, E3) does not include ultrasound parameters or individual risk calculation in specialized programs (PRISCA), and therefore has lower diagnostic sensitivity than the full combined screening.

Optimal timing:

16-18 weeks of pregnancy, acceptable range: 15th to 20th week.

Indications:

• for pregnant women as a baseline screening during the second trimester;
• if prenatal screening in the first trimester was not performed or was of limited reliability;
• if ultrasound signs of fetal pathology are detected;
• if there are abnormalities in biochemical parameters in the first trimester;
• in women with a high risk of chromosomal abnormalities:
  • age over 35;
  • history of chromosomal pathology;
  • aggravated family history. The indicators are interpreted without calculating the combined risk through software (PRISCA), and therefore may be less informative than with full combined screening.

The package is recommended for use:

• if an ultrasound has not yet been performed;
• for a preliminary indicative assessment;
• if necessary, perform rapid baseline testing;
• as part of a more comprehensive approach to fetal monitoring.

• Venous blood

In order to exclude factors that may affect the test results, we recommend to follow the preparation rules: