Sequential 1
Also known as: Down Syndrome, Nuchal Translucency (NT), PAPP-A
Use
Screening test for open neural tube defects, Down syndrome, and trisomy 18
Special Instructions
Client must provide fetal nuchal translucency (NT) measurement and crown rump length measurement. The NT measurement must be performed by a sonographer credentialed by the Fetal Medicine Foundation or other equivalent entity. Additional required information includes the patient's race, weight, date of birth, insulin-dependent diabetic status, and the number of fetuses. Complete information is necessary to interpret the test and can be provided using the Maternal Prenatal Screening requisition 0900.
Limitations
Sequential screening requires two specimens: one collected in the first trimester and one in the second trimester. This test number is for the first trimester portion only. Result interpretation for the first trimester is provided only for screen-positive specimens. Final results require the second trimester specimen. A positive result indicates that further diagnostic testing may be necessary to determine the presence of a neural tube defect or chromosome abnormality.
Methodology
Immunoassay (CLIA)
Biomarkers
LOINC Codes
- 49586-1
- 11957-8
- 34970-4
- 49089-6
- 18185-9
- 43993-5
- 21484-1
- 29463-7
- 11878-6
- 12146-7
- 49035-9
- 19080-1
- 32166-1
- 48407-1
- 76348-2
- 43995-0
- 49090-4
- 43994-3
- 47223-3
- 77202-0
- 11502-2
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
3 mL
Minimum Volume
1 mL
Container
Gel-barrier tube
Collection Instructions
Collect in serum separator tube with gel barrier. Allow blood to clot, avoiding hemolysis. Separate serum from cells by centrifugation. Transport spun tube to testing laboratory. Pour-off is not advised. Maternal serum specimens must be drawn prior to amniocentesis to avoid contamination with fetal blood.
Storage Instructions
Room temperature
Causes for Rejection
Gross hemolysis; gross lipemia; quantity not sufficient for analysis; improper specimen type
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 14 days |
| Frozen | 14 days |