SequentialScreen Part 2

CPT [MAAA: 81511] or 82105; 82677; 84702; 86336
  • AFP, Maternal
  • Down Syndrome

Test Details


Screening test for open neural tube defects, Down syndrome, and trisomy 18

Special Instructions

For test inquiries, call CMBP genetic services at 800-345-4363. Patient must have submitted a previous specimen in the first trimester for the Sequential 1 test. Gestational age will be based on crown rump length provided with the first trimester specimen. Patient information may be provided to the laboratory using the Maternal Prenatal Screening test request form 0900. Testing is provided from 15.0 to 21.9 weeks of gestation.


Sequential screening requires two specimens: one collected in the first trimester and one in the second trimester. This test number is for the second trimester portion of the test. 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.


Chemiluminescent immunoassay

Specimen Requirements

Information on collection, storage, and volume




5 mL

Minimum Volume

3 mL


Gel-barrier tube

Storage Instructions

Room temperature

Causes for Rejection

Gross hemolysis; gross lipemia; quantity not sufficient for analysis; improper specimen type


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.