First Trimester Screen With Nuchal Translucency
Also known as: First Trimester Screening, Combined Test
Use
Screening test in the first trimester of pregnancy for fetal Down syndrome and trisomy 18
Special Instructions
The test requires the client to provide necessary ultrasound measurements and patient information such as NT and CRL measurements, patient's weight, date of birth, and number of fetuses. The sonographer must be credentialed and their certification number provided. The test should be completed between 10.0 to 14.0 weeks' gestation.
Limitations
This screening test can indicate the likelihood of Down syndrome and trisomy 18 but cannot diagnose these conditions. It does not screen for open neural tube defects, and a positive result suggests further diagnostic testing may be required. MS-AFP in the second trimester is recommended for ONTD screening.
Methodology
Immunoassay (Chemiluminescent)
Biomarkers
LOINC Codes
- 48798-3
- 50679-0
- 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
- 23883-2
- 36904-1
- 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 and avoid hemolysis. Centrifuge to separate serum from cells. Do not use pour-off tubes. Draw specimens before amniocentesis to avoid contamination.
Storage Instructions
Room temperature
Causes for Rejection
Gross hemolysis; gross lipemia; insufficient quantity; improper specimen type.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 14 days |
| Frozen | 14 days |