Sequential 2
Also known as: AFP, Maternal, Down Syndrome
Use
Screening test for open neural tube defects, Down syndrome, and trisomy 18
Special Instructions
For accurate testing, the patient must have submitted a previous specimen in the first trimester for the Sequential 1 test. The gestational age is determined using the crown rump length provided with the first trimester specimen. The Maternal Prenatal Screening test request form (0900) should accompany the test. Testing is specifically for the period between 15.0 to 21.9 weeks of gestation.
Limitations
The Sequential 2 test can only be conducted if a specimen was provided in the first trimester under the Sequential 1 protocol. Results from this test are indicative and not diagnostic, meaning a positive screen indicates the need for further diagnostic testing to confirm neural tube defects or chromosomal abnormalities. The test is developed by LabCorp and is not cleared or approved by the FDA.
Methodology
Immunoassay (CLIA)
Biomarkers
LOINC Codes
- 29463-7
- 43993-5
- 21484-1
- 44877-9
- 11878-6
- 12146-7
- 49035-9
- 48407-1
- 76348-2
- 1834-1
- 23811-3
- 19080-1
- 32166-1
- 2250-9
- 21264-7
- 23883-2
- 36904-1
- 48803-1
- 43995-0
- 49090-4
- 43994-3
- 47223-3
- 49586-1
Result Turnaround Time
2-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
5 mL
Minimum Volume
3 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 |