四屏测试

定义

The quadruple screen test is a blood test done during pregnancy to determine whether the baby is at risk for certain birth defects.

选择的名字

Quad screen; Multiple marker screening; AFP plus; Triple screen test; AFP maternal; MSAFP; 4-marker screen; Down syndrome - quadruple; Trisomy 21 - quadruple; 特纳综合征 - quadruple; 脊柱裂 - quadruple; Tetralogy - quadruple; Duodenal atresia - quadruple; 遗传咨询 - quadruple; Alpha-fetoprotein quadruple; Human chorionic gonadotropin - quadruple; hCG - quadruple; Unconjugated estriol - quadruple; uE3 - quadruple; Pregnancy - quadruple; Birth defect - quadruple; Quadruple marker test; Quad test; Quadruple marker screen

如何执行测试

This test is most often done between the 15th and 22nd weeks of the pregnancy. It is most accurate between the 16th and 18th weeks.

A 血液样本 被送去实验室检测.

该测试测量4种妊娠激素的水平:

• Alpha-fetoprotein (AFP), a protein produced by the baby
• Human chorionic gonadotropin (hCG), a hormone produced in the placenta
• Unconjugated estriol (uE3), a form of the hormone estrogen produced in the fetus and the placenta
• 抑制素A，一种由胎盘释放的激素

If the test does not measure levels of inhibin A, it is called the triple screen test.

To determine the chance of your baby having a birth defect, the test also factors in:

• 你的年龄
• 你的种族背景
• 你的体重
• 宝宝的 孕龄 (measured in weeks from the day of your last period to the current date)

如何准备考试

No special steps are needed to prepare for the test. 你可以在考试前正常饮食.

考试的感觉如何

You may feel slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn.

为什么要进行测试

The test is done to find out if your baby might be at risk for certain birth defects, such as Down syndrome and birth defects of the spinal column and brain (called neural tube defects). This test is a screening test, so it does not diagnose problems.

Certain women are at greater risk of having a baby with these defects, 包括:

• 怀孕期间超过35岁的妇女
• 女性服用胰岛素治疗糖尿病
• 有出生缺陷家族史的女性

正常的结果

AFP, hCG, uE3，抑制素A正常.

Normal value ranges may vary slightly among different laboratories. Talk to your health care provider about the meaning of your specific test results.

异常结果意味着什么

An abnormal test result does NOT mean that your baby definitely has a birth defect. Often, the results can be abnormal if your baby is older or younger than your provider had thought.

如果结果不正常, you will have another ultrasound to check the age of the developing baby.

More tests and counseling may be recommended if the ultrasound shows a problem. However, some people choose not to have any more tests done, for personal or religious reasons. 下一步可能采取的措施包括:

• 羊膜穿刺术, which checks the AFP level in the amniotic fluid surrounding the baby. Genetic testing can be done on the amniotic fluid removed for the test.
• Tests to detect or rule out certain birth defects (such as Down syndrome).
• 遗传咨询.
• Ultrasound to check the baby's brain, spinal cord, kidneys, and heart.
• 产前无细胞DNA筛查, which uses cell-free DNA from the placenta and the fetus in the mother's bloodstream. A normal result might help avoid needing amniocentesis.

在怀孕期间, increased levels of AFP may be due to a problem with the developing baby, 包括:

• Absence of part of the brain and skull (anencephaly)
• Defect in the baby's intestines or other nearby organs (such as 十二指肠闭锁)
• Death of the baby inside the womb (usually results in a 流产)
• 脊柱裂 (脊柱缺陷)
• 法洛四联症 (心脏缺陷)
• 特纳综合征 (基因缺陷)

High AFP can also mean that you are carrying more than 1 baby.

Low levels of AFP and estriol and high levels of hCG and inhibin A may be due to a problem such as:

• 唐氏综合症(21三体)
• 爱德华兹综合症 (三染色体细胞18)

注意事项

The quadruple screen can have false-negative and false-positive results (although it is slightly more accurate than the triple screen). More tests are needed to confirm an abnormal result.

If the test is abnormal, you may need to talk to a genetic counselor.

参考文献

ACOG惯例公告第1号. 162: Prenatal diagnostic testing for genetic disorders. 比较。Gynecol. 2016;127(5):e108-e122. PMID: 26938573 pubmed.ncbi.nlm.国家卫生研究院.gov / 26938573 /.

Driscoll DA, Simpson JL. 遗传筛查和产前遗传诊断. [1]刘建军，刘建军，李建军，等. Gabbe's 产科: Normal and Problem Pregnancies. 7日艾德. Philadelphia, PA: Elsevier; 2021:chap 10.

韦伯杰，杜高夫. 先天性疾病的产前诊断. In: Resnik R, Lockwood CJ, Moore TR, Greene MF, Copel JA, Silver RM, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 8日艾德. Philadelphia, PA: Elsevier; 2019:chap 32.

Williams DE, Pridjian G. 产科. 见:Rakel RE, Rakel DP，编. 家庭医学教材. 9日艾德. Philadelphia, PA: Elsevier; 2016:chap 20.