Quad Screen
Also known as: AFP Quad Screen, Alpha-Fetoprotein, Maternal Serum
Use
Prenatal screening to assess fetal risk for trisomy 21 (Down syndrome), trisomy 18, and open neural tube defects (ONTD). A negative result indicates low likelihood but is not diagnostic; positive screening results warrant follow-up ultrasound for gestational dating and consideration of diagnostic testing or cell-free DNA screening. This test uses maternal serum analytes and demographic data to calculate risk assessments.
Special Instructions
Optimal specimen collection between 15.0 and 16.9 weeks gestational age; acceptable window for evaluation is 14.0–22.9 weeks. Specimens collected before or after this window cannot properly assess ONTD, trisomy 21, or trisomy 18 risks.
Limitations
This is a screening—not diagnostic—test. A negative screen does not guarantee a healthy baby. Positive results require follow-up confirmation. Gestational age must be accurate (±10 days) or may require recalculation or recollection. Should not be repeated if screen-positive. In New York, use alternate test code 82800A.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
3 mL
Minimum Volume
1 mL
Container
SST
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 28 days |