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Test Code QUAD2 Quad Screen

Specimen Required

3 mL serum

Specimen Minimum Volume

1 mL

Specimen Stability

Room temperature: 14 days Refrigerated: 14 days Frozen: 28 days

Rejection Due To

Gross hemolysis • Gross lipemia

Day(s) and Time(s) Performed

Set up: Mon-Sat; Report available: 3-4 days

Method Name

Immunoassay (IA)


AFP, unconjugated Estriol, hCG, Dimeric Inhibin A and Maternal Risk Interpretation

Collection Container / Tube

Preferred: Gold SST Tube
Other Acceptable Container: None

Transport / Storage Conditions

Room temperature

Special Instructions

The Quad test in pregnant women should be performed between 14.0 and 22.9 weeks gestational age, although the optimal period is 15.0-16.9 weeks. This time frame allows sufficient opportunity for further diagnostic studies if the initial Quad Screen test results are abnormal. Specimens submitted before 14.0 weeks or after 22.9 weeks gestation cannot be properly evaluated for open neural tube defects, Down Syndrome or Trisomy 18.

Note: For manual orders use "Maternal Serum Screen Requisition"
The Maternal Serum Screen Requisition designed to obtain patient data and the patient’s informed consent must be utilized when ordering the Quad Screen test. Because the Quad Screen test results are influenced by certain patient characteristics, the following data must be provided with the specimen in order to permit accurate interpretation of results: date of collection, patient’s (maternal) date of birth, patient’s estimated date of delivery, patient’s weight, patient’s race, patient’s diabetic status (is patient insulin dependent prior to pregnancy), number of fetuses, and whether this is a repeat sample.

Reference Values

See Laboratory Report

CPT Codes

This test is not available for California and New York patient testing. For New York patient testing use test code 16333.

Clinical Reference

Maternal serum Quad Screen is used for prenatal screening of Down syndrome (Trisomy 21), Trisomy 18 (Edwards syndrome), and open neural tube defects (ONTD). This profile includes alpha-fetaprotein (AFP), unconjugated estriol (µE3), human chorionic gonadotropin (hCG), and inhibin A. Establishing risk for fetal Down syndrome, using the quad screen achieves a 70-75% detection rate with a 5% false positive rate. Screening for Trisomy 18 detects 60% of affected fetuses with a 0.2% false positive rate. MSAFP screening detects 88% of anencephaly and 79% of open spina bifida with a 3% false positive rate. Normal results do not ensure birth of a normal infant. In addition, 2-3% of newborns have some type of physical or mental defect, many of which may be undetectable with current prenatal diagnostic procedures.


Quad Screen results consistent with an increased risk of trisomy should be confirmed with amniotic fluid specimen. Results consistent with increased risk of NTD may be followed-up with appropriate diagnostic testing as detailed in the report. Maternal serum screening yields a low percentage of false negatives. A wide range of other chromosomal abnormalities are not identified by maternal serum screening.