Stepwise, Part 2
Use
Prenatal screening that completes the Stepwise, Part 2 screen when a first-trimester Part 1 test has already been performed. It measures multiple serum markers—AFP, unconjugated estriol, hCG, inhibin A (dimeric), PAPP‑A, and hCG from Part 1—to refine the risk assessment for fetal trisomy 21 (Down syndrome), trisomy 18, and open neural tube defects in the second trimester of pregnancy.
Special Instructions
Not provided.
Limitations
A negative screen does not guarantee a healthy fetus; it only assesses risk for trisomy 21, trisomy 18, and ONTDs. Accuracy depends on accuracy of demographic data and gestational dating. Positive results warrant follow‑up diagnostic testing. Samples collected outside the 14.0–22 6/7 week window may be invalid. Demographic inaccuracies can lead to miscalculated risk.
Methodology
Immunoassay (Multiplex Protein Panel)
Biomarkers
Result Turnaround Time
Not provided.
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
3 mL
Minimum Volume
1 mL
Container
Transport tube
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
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