Quadruple screen test
Quad screen; Multiple marker screening; AFP plus; Triple screen test; AFP maternal; MSAFP; 4-marker screen; Down syndrome - quadruple; Trisomy 21 - quadruple; Turner syndrome - quadruple; Spina bifida - quadruple; Tetralogy - quadruple; Duodenal atresia - quadruple; Genetic counseling - 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 screenThe quadruple screen test is a blood test done during pregnancy to determine whether the baby is at risk for certain birth defects.
How the Test is Performed
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 blood sample is taken from the pregnant woman and sent to the lab for testing.
Blood sample
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
Read Article Now Book Mark ArticleThe test measures levels of 4 pregnancy hormones:
- 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
- Inhibin A, a hormone released by the placenta
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:
- Your age
- Your ethnic background
- Your weight
- Your baby's gestational age (measured in weeks from the day of your last period to the current date)
Gestational age
Gestation is the period of time between conception and birth. During this time, the baby grows and develops inside the mother's womb. Gestational ag...
Read Article Now Book Mark Article
How to Prepare for the Test
No special steps are needed to prepare for the test. You can eat or drink normally before the test.
How the Test will Feel
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.
Why the Test is Performed
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, including:
- Women who are over 35 years old during pregnancy
- Women taking insulin to treat diabetes
- Women with a family history of birth defects
Normal Results
Normal levels of AFP, hCG, uE3, and inhibin A.
Normal value ranges may vary slightly among different laboratories. Talk to your health care provider about the meaning of your specific test results.
What Abnormal Results Mean
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.
If you have an abnormal result, 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. Possible next steps include:
- Amniocentesis, 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.
Amniocentesis
Amniocentesis is a test that can be done during pregnancy to look for certain problems in the developing baby. These problems include:Birth defectsG...
Read Article Now Book Mark Article - Tests to check for certain birth defects (such as Down syndrome).
- Genetic counseling.
- Ultrasound to check the baby's brain, spinal cord, kidneys, and heart.
- Prenatal cell-free DNA screening, which uses cell-free DNA from the placenta and the fetus in the mother's bloodstream. A normal result might help avoid needing amniocentesis.
During pregnancy, increased levels of AFP may be due to a problem with the developing baby, including:
- Absence of part of the brain and skull (anencephaly)
- Defect in the baby's intestines or other nearby organs (such as duodenal atresia)
Duodenal atresia
Duodenal atresia is a condition in which the first part of the small bowel (the duodenum) has not developed properly. It is not open and does not al...
Read Article Now Book Mark Article - Death of the baby inside the womb (usually results in a miscarriage)
Miscarriage
A miscarriage is the spontaneous loss of a fetus before the 20th week of pregnancy. Pregnancy losses after the 20th week are called stillbirths. Mi...
Read Article Now Book Mark Article - Spina bifida (spinal defect)
Spina bifida
Myelomeningocele is a birth defect in which the backbone and spinal canal do not close fully before birth. The condition is a type of neural tube de...
Read Article Now Book Mark Article - Tetralogy of Fallot (heart defect)
Tetralogy of Fallot
Tetralogy of Fallot is a type of congenital heart defect. Congenital means that it is present at birth.
Read Article Now Book Mark Article - Turner syndrome (genetic defect)
Turner syndrome
Turner syndrome is a rare genetic condition in which a female does not have the usual pair of X chromosomes.
Read Article Now Book Mark Article
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:
- Down syndrome (trisomy 21)
- Edwards syndrome (trisomy 18)
Edwards syndrome
Trisomy 18 is a genetic disorder in which a person has a third copy of material from chromosome 18, instead of the usual 2 copies. Rarely, the extra...
Read Article Now Book Mark Article
Considerations
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.
References
ACOG Practice Bulletin No. 162: Prenatal diagnostic testing for genetic disorders. Obstet Gynecol. 2016;127(5):e108-e122. PMID: 26938573 pubmed.ncbi.nlm.nih.gov/26938573/.
Driscoll DA, Simpson JL. Genetic screening and prenatal genetic diagnosis. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 7th ed. Philadelphia, PA: Elsevier; 2021:chap 10.
Dugoff L, Wapner RJ. Prenatal diagnosis of congenital disorders. In: Lockwood CJ, Copel JA, Dugoff L, et al, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2023:chap 30.
Williams DE, Pridjian G. Obstetrics. In: Rakel RE, Rakel DP, eds. Textbook of Family Medicine. 9th ed. Philadelphia, PA: Elsevier; 2016:chap 20.
Quadruple screen - illustration
A blood test can be performed between the 15th and 22nd weeks of the pregnancy to determine whether the baby is at risk for certain birth defects. Blood is drawn from a vein and the sample is sent to a laboratory for testing. If the test is abnormal other tests can be performed to rule out birth defects.
Quadruple screen
illustration
Quadruple screen - illustration
A blood test can be performed between the 15th and 22nd weeks of the pregnancy to determine whether the baby is at risk for certain birth defects. Blood is drawn from a vein and the sample is sent to a laboratory for testing. If the test is abnormal other tests can be performed to rule out birth defects.
Quadruple screen
illustration
Review Date: 3/31/2024
Reviewed By: LaQuita Martinez, MD, Department of Obstetrics and Gynecology, Emory Johns Creek Hospital, Alpharetta, GA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.