Quadruple Marker Test: Purpose & Results

What Is the Quadruple Marker Test?

The quadruple marker test is a maternal serum screening test that measures four biochemical markers to estimate the risk of certain chromosomal abnormalities and neural tube defects in the developing fetus. These four markers include alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), unconjugated oestriol (uE3), and inhibin-A.

This screening test estimates the risk of Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and open neural tube defects such as spina bifida and anencephaly. It's designed to identify pregnancies that may benefit from further diagnostic testing, not to provide a definitive diagnosis.

When and Who Should Get the Quadruple Marker Test?

• Women aged 35 years or older at the time of delivery.
• Those with a family history of chromosomal abnormalities or birth defects.
• Previous pregnancy with chromosomal conditions or neural tube defects.
• Diabetic mothers using insulin during pregnancy.
• Those with abnormal ultrasound findings during routine scans.

The optimal timing for this test is between 15 and 20 weeks of gestation, with the most accurate results typically obtained between 16 and 18 weeks.

Step-by-Step: How the Quadruple Marker Test is Performed

1. You'll be seated comfortably for the blood draw.
2. A tourniquet is applied to your upper arm, and the puncture site is cleaned with an antiseptic.
3. A sterile needle is inserted into a vein, typically in your arm, and the required blood sample is collected.
4. The needle is removed, pressure is applied to prevent bleeding, and a bandage is applied.
5. Your sample is sent for analysis of the four specific markers.

Understanding the Four Markers: AFP, hCG, uE3 & Inhibin-A

Each component of the quadruple marker test provides specific information about your baby's development and potential risk factors. These four substances work together to create a comprehensive risk profile:

• Alpha-fetoprotein (AFP): It is produced by your baby's liver and indicates potential neural tube defects when elevated. Normal AFP levels suggest proper spinal cord and brain development.
• Human chorionic gonadotropin (hCG): It is the pregnancy hormone produced by the placenta. Abnormal hCG levels may indicate increased risk for Down syndrome or Edwards syndrome.
• Unconjugated estriol (uE3): This is a form of estrogen produced by both the placenta and the fetal liver. Low levels can suggest chromosomal abnormalities, particularly Down syndrome.
• Inhibin-A: It is produced by the placenta and ovaries. Elevated inhibin-A levels are associated with increased Down syndrome risk.

Interpreting Results: What a "Normal" or "High-Risk" Screen Means

Accuracy, Detection Rates & Limitations of the Quadruple Marker Test

• Down syndrome detection: Approximately 75–80% of affected pregnancies, with a false-positive rate of about 5%.
• Edwards syndrome detection: Detects about 60-70% of cases.
• Neural tube defects: Identify roughly 75-80% of open neural tube defects.
• False positives occur: High-risk results don't always indicate actual problems.
• False negatives are possible: Some affected pregnancies may show normal results.

What Happens After an Abnormal Result? Diagnostic Pathway Explained

If your quadruple marker test results indicate an increased risk, your healthcare provider will recommend additional evaluations, which may include a detailed ultrasound, genetic counseling, or confirmatory diagnostic testing. The next step typically involves a detailed ultrasound examination to look for physical signs of chromosomal conditions or structural abnormalities.

Genetic counselling is often recommended to help you understand what a positive quadruple marker test result means for your specific situation. A genetic counsellor can explain the risks, benefits, and limitations of further testing options such as amniocentesis or chorionic villus sampling, which can provide definitive diagnostic information.

Factors That Can Influence Test Accuracy

• Incorrect gestational age estimation can significantly impact marker interpretation.
• Maternal weight and BMI influence marker concentrations in blood.
• Multiple pregnancies (twins, triplets) alter expected marker levels.
• Poorly controlled maternal diabetes can lower AFP and uE3 levels, potentially affecting test interpretation.
• Ethnicity and race can influence baseline marker levels.
• Laboratory variations in measurement techniques or equipment calibration.

Quadruple Marker vs. Triple Marker vs. NIPT: Choosing the Right Screening

The triple marker test uses only three markers (AFP, hCG, and uE3), whilst the quadruple marker test adds inhibin-A for improved accuracy.

Non-invasive prenatal testing NIPT analyzes cell-free fetal DNA in maternal blood and offers higher accuracy for chromosomal conditions like Down syndrome and Edwards syndrome. However, NIPT doesn't screen for neural tube defects and is more expensive than the quadruple marker test.

Quadruple Marker Test in India: Cost, Access and Lab Quality

In India, the quadruple marker test price typically range from ₹3500 to ₹4500, depending on location and laboratory. Access may be more limited in rural areas, though telemedicine and mobile health services are expanding availability. Choosing a NABL- or CAP-accredited laboratory ensures quality control and standardized interpretation of quadruple marker test results.

Preparation, Safety & Risks of the Test

• No special dietary restrictions or fasting required before the test.
• Simple blood draw similar to routine blood tests during pregnancy.
• No risk to your baby, as the test only uses maternal blood.
• Safe for all pregnant women regardless of pregnancy complications.
• No recovery time needed following the blood collection.

Use of Results: What an Expectant Mother Should Ask Her Doctor

When receiving your quadruple marker test results, consider asking these important questions:

• What do my specific results mean for my baby's health and development?
• Do I need additional testing or follow-up based on these results?
• What are the risks and benefits of further diagnostic procedures if recommended?
• How accurate are these results considering my individual circumstances?
• Should I consult with a genetic counsellor to better understand the implications?
• Are there factors specific to my pregnancy that might affect the result's interpretation?

Conclusion

The quadruple marker test serves as a valuable screening tool during pregnancy, offering insights into your baby's health while maintaining safety for both mother and child. Understanding what the quadruple marker test is, how to interpret results, and when additional testing might be recommended empowers you to make informed decisions about your pregnancy care. Remember that a quadruple marker test normal report provides reassurance, while positive results simply indicate the need for further evaluation.

At Metropolis Healthcare, we understand the importance of accurate, reliable prenatal screening. With our comprehensive portfolio of more than 4,000 tests and a robust network of over 220 laboratories, we provide precise quadruple marker test results you can trust. Our home sample collection service, spanning 10,000+ touchpoints across India, ensures comfort and convenience during this important time in your pregnancy journey.

FAQs

Is the quadruple marker test mandatory during pregnancy?

The quadruple marker test is optional but strongly recommended as part of routine second-trimester prenatal screening, especially for women at increased risk, particularly for women with higher risk factors such as advanced maternal age or a family history of genetic conditions.

At what week is the best time to do the quadruple marker test?

The optimal timing for the quadruple marker test is between 16 and 18 weeks of pregnancy, though it can be performed from 15 to 22 weeks. Testing within this window ensures the most accurate quadruple marker test results.

What does a high-risk result on the quadruple marker test mean?

When a quadruple marker test is positive, it means a higher risk. It indicates an increased probability of screened conditions but doesn't confirm a diagnosis. Further testing, like ultrasound or amniocentesis, may be recommended for definitive answers.

How accurate is the quadruple marker test compared to NIPT?

NIPT offers higher accuracy for chromosomal abnormalities with fewer false positives, but the quadruple marker test screens for neural tube defects that NIPT cannot detect. The choice depends on your specific screening goals and risk factors.

Can the quadruple marker test guarantee a healthy baby?

No prenatal screening test can guarantee a completely healthy baby. The quadruple marker test only assesses risk for specific conditions, Down syndrome, Edwards syndrome, and neural tube defects, not all possible health issues.

What is the cost of the quadruple marker test in India?

The quadruple marker test typically costs between ₹3500 and ₹4500 in India, varying by location and laboratory quality.

What happens if I miss the 15-20 week window for the test?

If you miss the optimal time window, the test’s accuracy declines because marker concentrations vary by gestational age; your doctor may suggest alternative options such as NIPT or detailed anomaly scan. Your doctor may recommend alternative screening methods or targeted ultrasounds instead.

Can my weight or having twins affect the quadruple marker test result?

Yes, maternal weight and multiple pregnancies significantly affect marker concentrations, potentially influencing quadruple marker test results. Laboratories adjust calculations based on these factors to improve accuracy.

What is the difference between the triple marker and quadruple marker tests?

The difference between a triple marker and a quadruple test lies in the number of substances measured. The quadruple test adds inhibin-A to improve Down syndrome detection compared to the three-marker version.

Are there any risks to the baby from the quadruple marker test?

The quadruple marker test poses no risks to your baby, as it only requires a maternal blood sample. It's completely non-invasive and safe for both mother and baby throughout pregnancy.

References

• https://my.clevelandclinic.org/health/diagnostics/4698-pregnancy-quad-marker-screen
• https://pmc.ncbi.nlm.nih.gov/articles/PMC9210531/
• https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/quadruple-screening-test/
• https://americanpregnancy.org/prenatal-testing/quad-screen/
• https://pubmed.ncbi.nlm.nih.gov/21706514/