Prenatal Testing: NIPT, Combined, Triple and Quad Screening

Türkçe okuyun

Dr. Alparslan Demir · Obstetrics and Gynaecology

Prenatal testing starts with a question I encourage you to ask: “What will this test actually tell me?” I first review your pregnancy dates, ultrasound and history, then discuss the scope and limitations of each option. The NIPT, combined, triple and quad tests described here are chromosome-risk screening tests; they are not diagnostic tests.

How do NIPT and the combined test differ?

The blood component often called the “double test” in Türkiye measures PAPP-A and free beta-hCG. Combined screening brings these markers together with maternal age and ultrasound findings such as nuchal translucency. NIPT analyses cell-free DNA in maternal blood; the pregnancy-related component comes mainly from the placenta. Common panels assess the chance of trisomies 21, 18 and 13, with scope varying by laboratory. NHS: Combined screening NHS Genomics: NIPT

When can I have the tests?

NIPT is commonly available from 10 weeks. The ultrasound part of combined screening is usually arranged between 11 weeks and 13 weeks 6 days, when fetal measurements are suitable. Triple and quad tests are second-trimester blood tests, often performed at 15–20 weeks; the laboratory’s accepted window must be checked. Triple screening measures AFP, hCG and estriol, while quad screening adds inhibin A. I review dates with you before arranging testing. MedlinePlus: NIPT Office on Women’s Health: Prenatal tests

Which option fits my risk profile?

Screening is not reserved for older pregnant women. NIPT or an appropriate serum-screening approach can be discussed in a pregnancy without a known additional risk. Age, previous results, family history, access and your preferences inform the decision. With an abnormal ultrasound, a high-chance screen or a known genetic risk, I discuss genetic counselling and diagnostic testing rather than assuming another screen will answer the question. Unrelated screening tests for the same chromosome risk should not simply be stacked together.

What do high chance, low chance and no result mean?

A high-chance or positive screen does not establish that the baby is affected. A low-chance result does not exclude every genetic condition. A “no result” report is not a normal result: low DNA levels or other factors may be involved. The next step may be another sample, further assessment or a diagnostic test, depending on the circumstances. MedlinePlus: Interpreting NIPT

What happens after a positive screen?

I first explain the specific condition and risk reported, then arrange appropriate ultrasound review and genetic counselling. Chorionic villus sampling at an appropriate gestation or amniocentesis, generally from 15 weeks, may be offered for diagnosis. We discuss the information expected and procedure-related risks. Irreversible pregnancy decisions should not rest on a screening result alone. NHS: Amniocentesis

Questions you may want to ask

My NIPT was low risk. Do I still need the anatomy scan?

Yes. Chromosome screening and structural assessment answer different questions. A low-risk NIPT does not replace a detailed ultrasound.

Would doing every test be safer?

The aim is an appropriate testing strategy, not the largest number of tests. Bring previous reports so we can assess what has already been answered and avoid unnecessary duplication.

Related pregnancy guides

For the difference between chromosome screening, anatomical assessment and volume imaging, read 3D and 4D ultrasound: timing and limitations.

• Level 2 Ultrasound: Detailed Anomaly Scan in Istanbul
• NST (Non-Stress Test): Timing, Procedure and Results
• Pregnancy follow-up (Turkish)

For an individual assessment and an appointment, contact the practice (contact page in Turkish).

You do not need to send detailed health information or test reports just to request an appointment. Personal data information (Turkish)

This page provides general health information and does not replace individual medical advice. The need for examination, biopsy or treatment is determined through clinical assessment.