Sequential Integrated Screen, Part 1
Use
Sequential Integrated Screen, Part 1 combines first‑trimester markers including PAPP‑A, hCG, and nuchal translucency to assess risk of Down syndrome (trisomy 21) and trisomy 18 during early pregnancy (first trimester) ([questdiagnostics.com](https://www.questdiagnostics.com/healthcare-professionals/about-our-tests/womens-health/pregnancy-and-fertility/pregnant-patients/testing-for-each-trimester?utm_source=openai)).
Special Instructions
Not provided.
Limitations
This is a screening, not a diagnostic test. Gestational age must be accurate—calculated from crown‑rump length or EDD. Changing gestational age outside ±7 days may require resampling. In twin gestations, trisomy 18 risk may not be reported; results reflect pseudo‑risk, not fetus‑specific risk ([questdiagnostics.com](https://www.questdiagnostics.com/healthcare-professionals/clinical-education-center/faq/faq89?utm_source=openai)).
Methodology
Immunoassay
Biomarkers
LOINC Codes
- 49090-4 - Fet Ts 21 risk from Mat age
- 11884-4 - GA Clin est
- 23841-0 - B-HCG adj MoM SerPl
- 21198-7 - B-HCG SerPl-aCnc
- 49586-1 - Integrated scn Patient-Imp
- 43995-0 - Ts 21 risk Fetus
- 43994-3 - Ts 18 risk Fetus
- 48407-1 - PAPP-A SerPl-mCnc
- 32123-2 - PAPP-A MoM SerPl
Result Turnaround Time
8 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
Not provided
Minimum Volume
Not provided
Container
SST
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 28 days |
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