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For hours, walk-ins and appointments.Synonyms
- Down Syndrome
- Nuchal Translucency (NT)
- PAPP-A
Special Instructions
For test inquiries, call CMBP genetic services at 800-345-4363. 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. The sonographer's credential/certification number must be provided. The following information also must be provided: patient's race, patient's weight, patient's date of birth, patient's insulin-dependent diabetic status, and the number of fetuses. Also indicate patient history (i.e. prior Down syndrome pregnancy, ultrasound anomalies). Complete information is necessary to interpret the test. Patient information may be provided to the laboratory using the Maternal Prenatal Screening requisition 0900. Serum testing is provided from 10.0 to 14.0 weeks of gestation. NT can be assessed when the CRL is 45 to 84 mm.
Expected Turnaround Time
2 - 5 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Information
Related Documents
Specimen Requirements
Specimen
Serum
Volume
3 mL
Minimum Volume
1 mL
Container
Gel-barrier tube
Collection
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
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 7 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Causes for Rejection
Gross hemolysis; gross lipemia; quantity not sufficient for analysis; improper specimen type
Test Details
Use
Screening test for open neural tube defects, Down syndrome, and trisomy 18
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 of the test. Result interpretation for the first trimester portion will be provided only for screen-positive specimens. Result interpretation for all others will be provided only when the second trimester specimen is received and tested. This is a screening test. A positive result means that diagnostic testing may be offered to the pregnant woman to determine if a neural tube defect or chromosome abnormality is present.
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Methodology
Chemiluminescent immunoassay
References
Wald NJ, Rudnicka AR, Bestwick JP. Sequential and contingent prenatal screening for Down syndrome. Prenat Diagn. 2006 Sep; 26(9):769-777.16821246
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 017700 | Sequential 1 | 017859 | Results | N/A | ||
| 017700 | Sequential 1 | 017701 | Test Results: | 49586-1 | ||
| 017700 | Sequential 1 | 017703 | Submit Part 2 Sample Using | N/A | ||
| 017700 | Sequential 1 | 017704 | Crown Rump Length | mm | 11957-8 | |
| 017700 | Sequential 1 | 018064 | Crown Rump Length Twin B | mm | 11957-8 | |
| 017700 | Sequential 1 | 017705 | CRL Scan | 34970-4 | ||
| 017700 | Sequential 1 | 018065 | CRL Scan Twin B | 34970-4 | ||
| 017700 | Sequential 1 | 018021 | Sonographer ID# | 49089-6 | ||
| 017700 | Sequential 1 | 017706 | Gest.Age on Collection Date | weeks | 18185-9 | |
| 017700 | Sequential 1 | 017708 | Maternal Age at EDD | yr | 43993-5 | |
| 017700 | Sequential 1 | 017709 | Race | 21484-1 | ||
| 017700 | Sequential 1 | 017710 | Weight | lbs | 29463-7 | |
| 017700 | Sequential 1 | 017711 | Number of Fetuses | 11878-6 | ||
| 017700 | Sequential 1 | 017712 | Nuchal Translucency (NT) | mm | 12146-7 | |
| 017700 | Sequential 1 | 017713 | Nuchal Translucency MoM | 49035-9 | ||
| 017700 | Sequential 1 | 018063 | NT Twin B | mm | 12146-7 | |
| 017700 | Sequential 1 | 018070 | NT MoM Twin B | 49035-9 | ||
| 017700 | Sequential 1 | 018173 | Additional US | N/A | ||
| 017700 | Sequential 1 | 017362 | hCG Value | IU/mL | 19080-1 | |
| 017700 | Sequential 1 | 017716 | hCG MoM | 32166-1 | ||
| 017700 | Sequential 1 | 018217 | PAPP-A Value | ng/mL | 48407-1 | |
| 017700 | Sequential 1 | 017718 | PAPP-A MoM | 76348-2 | ||
| 017700 | Sequential 1 | 018087 | Down Syndrome | 43995-0 | ||
| 017700 | Sequential 1 | 018089 | Down Syndrome | 49090-4 | ||
| 017700 | Sequential 1 | 018090 | Trisomy 18 | 43994-3 | ||
| 017700 | Sequential 1 | 018091 | Trisomy 18 | 47223-3 | ||
| 017700 | Sequential 1 | 017702 | Down Syndrome Interpretation | 49586-1 | ||
| 017700 | Sequential 1 | 017724 | Trisomy 18 Interpretation | 49586-1 | ||
| 017700 | Sequential 1 | 017288 | Comments: | 77202-0 | ||
| 017700 | Sequential 1 | 017854 | Note: | N/A | ||
| 017700 | Sequential 1 | 511933 | 11502-2 |
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