Laboratory Test Information Guide

Details for Maternal Serum Screen (for Open Neural Tube Defect and Down Syndrome Risks)

Test Name: Maternal Serum Screen (for Open Neural Tube Defect and Down Syndrome Risks)
Alternate Name(s): Enhanced First Trimester Screen
Integrated Prenatal Screen
Triple Marker
Triple Screen
Down Syndrome Screen
Alphafetoprotein (Pregnancy)
Open Neural Tube Defect (ONTD)
Open Spina Bifida (OSB)
Laboratory: Core
Specimen Type: 5 mL Gold top Vacutainer tube preferred

6 mL Red top Vacutainer is also accepted

Light Green top tubes (Li-heparin) or Lavender top tubes (EDTA) are not acceptable
Collection Information:  
Requisition: North York General Hospital Prenatal Screening Requisition Form
Test Schedule: Referred out Monday-Friday
Turnaround time from when specimen
is received in testing laboratory:
5 days
Reference Range: Not available. Result depends on clinical information.
Effective Date: 2009-02-12
Revised Date: 2020-04-01
Critical Value:  
Interpretive Comments: Risks generated are dependent on accuracy and completeness of clinical information provided on the prenatal screening requisition form.
Special Processing: Once the blood has clotted and been centrifuged, transfer a minimum of 2 mL of serum to a labelled plastic transport tube.
Comments: The NYGH MSS laboratory will fax results directly to the ordering provider and any other health care providers, as requested on the prenatal screening requisition form.
Method of Analysis: Immunofluorescence (Perkin Elmer AutoDELFIA)
Critical Information Required:  
Storage & Shipment: If serum has been collected before a weekend and will not be received by the NYGH MSS lab until after the weekend, the aliquoted serum should be frozen.

Refrigeration is acceptable if the serum will be received by the NYGH MSS lab within 1-2 days of collection.

NYGH Prenatal Screening Requisition Form should be shipped with the sample.
System Codes: 
Referred To: North York General Hospital
Genetics, Maternal Serum Screening Laboratory, 3SE
4001 Leslie Street
Toronto, ON
M2K 1E1
Phone: 416-756-6055, extension 3
Fax: 416-756-6108

(Samples collected at LHSC are shipped to the NYGH MSS lab via LifeLabs)

Questions? Comments? Contact Laura Gopaul