One 7.5 mL serum separator tube (SST). Also acceptable: One 5 mL red top tube. NOTE: Order on OML’s obstetrics requisition or electronically and include the following required information: patient’s date of birth, current weight, due date, dating method (US, LMP), number of fetuses present, patient’s race, if patient requires insulin, if there is a previous child with neural tube defects; and for in vitro fertilization pregnancies, the age of the egg donor.
Allow to clot, centrifuge and separate serum from cells and pour into a plastic vial immediately. .
8 hours ambient, 7 days refrigerated, or 3 months frozen.
1 mL serum.
0.5 mL serum.
Refrigerated, or frozen, on dry ice.
Optimum time for screening is between 16-18 weeks gestation. NTD RISK can be performed between 15 weeks, 0 days and 21 weeks, 6 days gestation. For Neural Tube Defect Risk only in second trimester. For Down syndrome risk order Down/Neural Tube Defect Quad Marker (41955).
Specimen frozen and thawed more than once.
MEDICARE MAY REQUIRE A SIGNED ADVANCE BENEFICIARY NOTICE (ABN) FOR THIS TEST