Maternal Serum AFP

The Maternal Serum AFP test contains 1 test with 20 biomarkers.

Brief Description: The Maternal Serum Alpha-fetoprotein (AFP) test is a screening test performed during pregnancy to measure the level of AFP in the mother's bloodstream. AFP is a protein produced by the liver of the fetus and crosses into the mother's blood. The amount of AFP in the blood can be used to help identify certain potential health issues in the baby.

Collection Method: Blood Draw

Specimen Type: Serum

Test Preparation: No preparation required

When and Why a Maternal Serum AFP Test May Be Ordered

The Maternal Serum AFP test is typically ordered between the 15th and 20th weeks of pregnancy. It's considered part of routine prenatal care and is often ordered to:

1. Screen for Neural Tube Defects (NTDs): Such as spina bifida, where the spinal column doesn’t close completely, or anencephaly, a severe brain defect.
2. Screen for Abdominal Wall Defects: Like gastroschisis or omphalocele where the intestines or other organs protrude outside the body.

What a Maternal Serum AFP Test Checks For

The test specifically measures the levels of AFP in the maternal serum. High levels can suggest potential neural tube defects or abdominal wall defects. Lower than expected AFP levels might indicate other conditions, such as Down syndrome.

Other Lab Tests Ordered Alongside a Maternal Serum AFP Test

A Maternal Serum AFP test is often part of a larger panel of prenatal screening tests called a "multiple marker" or "quad" screen. Along with AFP, the following tests might be ordered:

1. hCG: Human chorionic gonadotropin, a hormone produced by the placenta.
2. Estriol: A hormone produced by both the fetus and the placenta.
3. Inhibin A: Another hormone produced by the placenta.

The combination of these tests can help determine the risk of the fetus having certain chromosomal conditions, like Down syndrome (trisomy 21) or Edwards syndrome (trisomy 18).

Conditions or Diseases Requiring a Maternal Serum AFP Test

The Maternal Serum AFP test is used to screen for:

1. Neural Tube Defects: Like spina bifida and anencephaly.
2. Abdominal Wall Defects: Such as gastroschisis or omphalocele.
3. Down Syndrome: While an increased level of AFP indicates a higher risk of neural tube defects, a lower level can be a sign of Down syndrome.
4. Edwards Syndrome: This test, especially when combined with other markers, can indicate the potential for trisomy 18 or Edwards syndrome.

How Health Care Providers Use the Results of a Maternal Serum AFP Test

Health care providers interpret the results of the AFP test in the context of the mother’s age, weight, and race, as well as the gestational age of the fetus:

• Increased AFP Levels: If levels are high, additional tests like ultrasound or amniocentesis may be recommended to confirm neural tube or abdominal wall defects.

• Decreased AFP Levels: Lower levels might lead to recommendations for other screenings or diagnostic tests to rule out chromosomal abnormalities like Down syndrome.

• Inconclusive Results: Sometimes, results might be inconclusive. In such cases, the test might be repeated, or other tests may be recommended.

It's essential to understand that the Maternal Serum AFP test is a screening tool, not a diagnostic test. This means that it can identify the potential risk of certain conditions, but it cannot diagnose them. If abnormal AFP levels are found, further diagnostic testing is typically offered to confirm or rule out potential conditions.

Most Common Questions About the Maternal Serum AFP test:

Purpose and Clinical Indications

Why is the Maternal Serum AFP test performed?

The Maternal Serum AFP test is primarily performed to assess the risk of certain birth defects in an unborn baby. AFP (Alpha-fetoprotein) is a protein that's produced by the liver of the fetus. The test measures the amount of AFP in the pregnant mother's blood to detect neural tube defects, such as spina bifida and anencephaly. It can also help detect certain chromosomal abnormalities like Down syndrome, though it's not the primary test for this purpose.

When during pregnancy is the Maternal Serum AFP test typically recommended?

The Maternal Serum AFP test is typically recommended between the 15th and 20th weeks of pregnancy, with the optimal time being around the 16th to 18th weeks. Testing before or after this window can increase the chance of inaccurate results.

Interpretation of Results

What does a higher-than-normal level of AFP in the Maternal Serum AFP test indicate?

A higher-than-normal level of AFP in the Maternal Serum AFP test can suggest that the fetus has a neural tube defect such as spina bifida or anencephaly. However, high AFP levels can also result from a miscalculated due date, as the levels of AFP change throughout pregnancy. Other possibilities for elevated AFP include multiple pregnancies (like twins or triplets) or abdominal wall defects in the fetus.

What could a lower-than-normal level of AFP in the Maternal Serum AFP test suggest?

A lower-than-normal level of AFP might suggest chromosomal abnormalities in the fetus, like Down syndrome. However, the Maternal Serum AFP test alone isn't enough to diagnose these conditions, and other diagnostic tests, like amniocentesis or chorionic villus sampling, may be required for confirmation.

Clinical Implications

If the Maternal Serum AFP test yields abnormal results, what are the subsequent steps or tests?

If the Maternal Serum AFP test shows abnormal results, additional testing is typically recommended to provide a clearer picture. This can include a detailed ultrasound to check the baby's anatomy and look for signs of birth defects. In cases where chromosomal abnormalities are suspected, invasive tests like amniocentesis or chorionic villus sampling might be recommended for a definitive diagnosis.

How does the Maternal Serum AFP test differ from other prenatal screening tests?

The Maternal Serum AFP test specifically measures the level of AFP in the mother's blood to screen for certain birth defects. Other prenatal screening tests might measure different markers or combinations of markers to assess the risk for chromosomal abnormalities or other genetic disorders. The Maternal Serum AFP test is often part of a series of tests known as the "multiple marker" or "quadruple screen" tests. The combination of these tests provides a more comprehensive assessment of potential fetal abnormalities.

We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.