Double Marker Test (8-13.6 Weeks) – Free β-hCG & PAPP-A

The Double Marker Test is a prenatal screening test performed during 8 to 13.6 weeks of pregnancy. It helps assess the risk of chromosomal abnormalities like Down Syndrome (Trisomy 21), Trisomy 18, and Trisomy 13 in the fetus.

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Tests Included in the Double Marker Test:

1. Free Beta-hCG (β-hCG – Free Beta Human Chorionic Gonadotropin)
2. PAPP-A (Pregnancy-Associated Plasma Protein-A)

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1. Free Beta-hCG (β-hCG)

Purpose:

• hCG is a hormone produced by the placenta.
• High or low levels indicate chromosomal abnormalities in the fetus.

🔹 Normal Range (Varies by Pregnancy Weeks):

• A high level of β-hCG may indicate Down Syndrome (Trisomy 21).
• A low level may indicate Trisomy 18 or Trisomy 13.

✅ Precautions:

• No fasting required.
• Avoid stress and maintain a balanced diet before the test.

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2. PAPP-A (Pregnancy-Associated Plasma Protein-A)

Purpose:

• A protein produced by the placenta; essential for normal fetal growth.
• Abnormal levels may indicate a higher risk of chromosomal disorders.

🔹 Normal Range:

• Low PAPP-A levels may indicate Down Syndrome (Trisomy 21) or other chromosomal issues.
• Very low levels may suggest pregnancy complications (e.g., preeclampsia, growth restriction).

✅ Precautions:

• No fasting required.
• Inform the doctor of medications or medical conditions.

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Who Should Take the Double Marker Test?

✔ Women aged 35 years or above (higher risk of chromosomal abnormalities).
✔ If there’s a family history of genetic disorders.
✔ If previous pregnancies had chromosomal abnormalities.
✔ If a NT scan (Nuchal Translucency) shows increased thickness.

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Final Summary & Precautions

Test	Fasting Required?	Purpose
Free β-hCG	❌ No	Detects chromosomal abnormalities
PAPP-A	❌ No	Predicts fetal chromosomal & pregnancy risks

General Precautions:

✔ No fasting required.
✔ Best performed between 8 to 13.6 weeks of pregnancy.
✔ Results are combined with the NT Scan for accurate risk assessment.
✔ It is a screening test, not a diagnostic test—further tests like NIPT or Amniocentesis may be needed if the results indicate a high risk.