When is triple screen performed

Sometimes negative test results can be wrong too. They may show that the baby is fine when he or she does have a birth defect. This is a false-negative test result. Your doctor will use your age and your baby's age to interpret the test results. If your test results are abnormal, your doctor may use a fetal ultrasound to make sure of your baby's age.

A "positive" result means that there is a higher-than-average chance your baby has a birth defect. If the result is "negative," or normal, it means that your baby probably doesn't have a birth defect. But it doesn't guarantee that you will have a normal pregnancy or baby. Your doctor may tell you the result of your test as a set of numbers. Doctors often use a certain number as a cutoff for a positive result.

For example, your doctor may say the cutoff is 1 out of This means that if your result is 1 out of or 1 out of a number less than such as 1 out of , you have a positive result and your baby has a higher chance of a birth defect.

If your result is 1 out of , this means that you have a negative result and your baby has a lower chance of a birth defect. If you have a positive test result, your doctor may want you to have the diagnostic test amniocentesis to find out for sure if there is a problem. But it's your choice whether to have another test.

If you have a negative result, you may choose not to have another test. Deciding whether to have a test for birth defects is a personal decision. And it can be a hard choice. You need to think about what the results of a test would mean to you and how they might affect your choices about your pregnancy.

If you choose to have a test, you may want to talk with a genetic counsellor. The counsellor can talk with you about the reasons to have or not have the test.

He or she can also help you find other resources for support and decision-making. For more help on deciding about having a triple or quad screening, see the topic:. Author: Healthwise Staff. This information does not replace the advice of a doctor. Healthwise, Incorporated, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Learn how we develop our content.

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Contact afpserv aafp. Want to use this article elsewhere? Get Permissions. Read the Issue. Sign Up Now. Previous: What Are Lipomas? Mar 1, Issue. What is a triple screen? These tests can't show for sure that your baby has a birth defect.

You would need a diagnostic test called amniocentesis to find out for sure if there is a problem. The triple or quad screening is usually done at 15 to 20 weeks of pregnancy.

Each substance tested in a triple or quad screening gives you different information about possible problems. Together, these results give the best information. These screening tests look for the amount of:. Your doctor will look at the levels of these substances—along with your age and other factors—to see if your baby has a higher-than-average chance of having a birth defect. A simple blood test is all that's needed for these tests. The health professional taking a sample of your blood will:.

A screening test shows the chance that a baby has a certain birth defect. The accuracy of a screening test is based on how often the test correctly finds a birth defect. With the triple or quad test, there is a chance of getting a false-positive test result. This means that the test could show a problem when the baby doesn't have the problem.

A false positive may be more likely with the triple screening than the quad screening. A false-positive result can cause stress and lead to unnecessary testing such as an amniocentesis. Many women who have a positive screening test result are actually carrying a healthy baby.

Sometimes negative test results can be wrong too. They may show that the baby is fine when he or she does have a birth defect. This is a false-negative test result. Your doctor will use your age and your baby's age to interpret the test results. If your test results are abnormal, your doctor may use a fetal ultrasound to make sure of your baby's age.

A "positive" result means that there is a higher-than-average chance your baby has a birth defect. If the result is "negative," or normal, it means that your baby probably doesn't have a birth defect. But it doesn't guarantee that you will have a normal pregnancy or baby. Your doctor may tell you the result of your test as a set of numbers.

Doctors often use a certain number as a cutoff for a positive result. For example, your doctor may say the cutoff is 1 out of This means that if your result is 1 out of or 1 out of a number less than such as 1 out of , you have a positive result and your baby has a higher chance of a birth defect. If your result is 1 out of , this means that you have a negative result and your baby has a lower chance of a birth defect.

If you have a positive test result, your doctor may want you to have the diagnostic test amniocentesis to find out for sure if there is a problem. But it's your choice whether to have another test.

If you have a negative result, you may choose not to have another test.